JP2008177697A - Capacitor microphone unit and capacitor microphone - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a capacitor microphone unit having a structure capable of preventing trouble such that a damper shifts in position in a stage of engaging a fixed electrode with an insulating seat, and a capacitor microphone using the same. <P>SOLUTION: The capacitor microphone unit 10 is constituted by incorporating, in a unit case 11, at least a diaphragm 13, the fixed electrode 15 disposed opposite the diaphragm leaving a gap to constitute a capacitor with the diaphragm, the insulating seat 16 disposed on the rear side of the fixed electrode to support the fixed electrode, an annular acoustic resistance member 17 disposed on the front side of the insulating seat, an annular damper 18 which presses the acoustic resistance member against the insulating seat from the front side. Further, the capacitor microphone unit has a fixed member 19 which presses the damper 18 from the front side. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a condenser microphone unit and a condenser microphone, and more particularly to a technique for improving variations in acoustic resistance values for controlling directivity in a condenser microphone.

  The condenser microphone includes a condenser microphone unit that constitutes a kind of condenser in which a diaphragm that vibrates by sound waves and a fixed pole (also referred to as a “back pole”) are disposed to face each other with a spacer interposed therebetween. The condenser microphone unit is assembled in a unit case, and further includes an FET (field effect transistor) as an impedance converter and a circuit board on which the FET is mounted.

In such a condenser microphone, there are mainly the following two methods for forming an acoustic resistance that restricts the sound wave guided to the diaphragm and imparts the desired directivity.
One of them is that a plate coupled to a diaphragm via a spacer is disposed on an insulating seat, and an acoustic resistance is formed between the insulating seat and the plate by a thin air layer corresponding to the thickness of the spacer. is there. The other is to arrange an acoustic resistance member and a plate coupled to the diaphragm on the insulating seat so as to cover the sound communication hole.

In the condenser microphone having an acoustic resistance like the former, several means for improving directivity have been proposed (for example, refer to Patent Documents 1 and 2).
In addition, a means for improving directivity in a condenser microphone having an acoustic resistance like the latter has been proposed (see, for example, Patent Document 3).

The basic configuration of the condenser microphone unit in the condenser microphone having the acoustic resistance as described above is as shown in FIG.
In FIG. 5, the condenser microphone unit 110 is configured by housing the following parts in a cylindrical unit case 111 with a bottom. The unit case 111 has a front portion corresponding to the bottom portion 111a, and a plurality of holes 122 for introducing sound into the unit are formed in the bottom portion 111a. In the unit case 111, a ring-shaped diaphragm holder 112 and an outer peripheral edge are fixed to one end surface of the diaphragm holder via a dust-proof member 125 at a position closest to the bottom 111a of the unit case 111. A diaphragm 113 is disposed.
A fixed pole 115 is disposed opposite to the diaphragm 113 via a spacer 114 that is a ring-shaped member. A gap corresponding to the thickness of the spacer 114 is formed between the diaphragm 113 and the fixed electrode 115 to constitute a kind of capacitor. As the diaphragm 113 vibrates according to the sound introduced from the hole 122, the capacitance of the capacitor changes, and the change in capacitance is output as a sound signal.

In the unit case 111, an insulating seat 116 as a fixed pole support is disposed on the rear surface side of the fixed pole 115. The insulating seat 116 is made of, for example, synthetic resin, and a circular recess is formed on the front side thereof. The fixed pole 115 is fitted in the recessed portion. The concave portion is also formed with a ring-shaped concave portion on the inner peripheral side of the concave portion, and the ring-shaped acoustic resistance member 117 and the elastic damper 118 are fitted into the ring-shaped concave portion. It has been.
A disc-shaped printed circuit board 121 is disposed on the rear surface side of the insulating seat 116 and is in contact with the outer peripheral edge thereof. On the outer peripheral edge of the rear surface of the printed circuit board 121, a folded portion 123 at the open end edge of the unit case 111 is located. The printed circuit board 121 is pushed forward (upward in FIG. 5) by the pressing force of the folded portion 123. By this pressing force, the insulating seat 116 is pressed, the fixed pole 115 is pressed through the damper 118, and the diaphragm 113 and the diaphragm holder 112 are pressed against the bottom surface 111a of the unit case 111 through the spacer 114. These members are respectively positioned and fixed in the unit case 111.

  A hole is formed in the central portion of the insulating seat 116 in the thickness direction, and a small diameter portion of a contact 119 made of a metal such as copper and having different diameters is fitted into the hole. On the printed circuit board 121, a field effect transistor (hereinafter referred to as “FET”) 120 constituting an impedance converter is disposed at a position facing the contact 119. A part of the terminal 120 a of the FET 120 is bent along the exterior of the FET 120 and is in contact with the lower surface 119 b of the contact 119. On the other hand, one of the other terminals 120b is connected to a predetermined circuit pattern of the printed circuit board 121 by soldering or the like. A coiled contact spring 124 is compressed and disposed on the outer peripheral side of the upper end 119a of the contact 119. The contact spring 124 is interposed between the fixed pole 115 and the contact 119 and urges the contact 119 and the fixed pole 115 in a direction to separate them from each other. With this urging force, the contact 119 is pressed against one of the terminals 120 a of the FET 120 to establish electrical continuity between the terminal 120 a and the fixed electrode 115.

In the condenser microphone unit 110 described above, the acoustic resistance member 117 is pressed against the insulating seat 116 with the damper 118, thereby realizing a stable and uniform acoustic resistance.
Therefore, when the condenser microphone unit 110 is assembled, the acoustic resistance member 117 and then the damper 118 are placed on the insulating seat 116, and then the fixed electrode 115 is fitted to the insulating seat 116. Accordingly, the damper 118 is sandwiched between the fixed electrode 115 and the insulating seat 116, and a stable pressure can be applied to the acoustic resistance member 117.

However, as shown in FIG. 6, after placing the acoustic resistance member 117 on the insulating seat 116 and further placing the damper 118 on the acoustic resistance member 117, the fixed electrode 115 is press-fitted into the insulating seat 116 to fit them together. In the process of making it, there exists a problem that the position of the damper 118 will shift | deviate. As a result, the peripheral portion 118a of the damper 118 may be sandwiched between the portions where the fixed pole 115 of the insulating seat 116 contacts (fitting). Therefore, the fixed pole 115 is attached in a state tilted with respect to the insulating seat 116, resulting in poor sensitivity and frequency response.
In addition, since the acoustic resistance member 117 cannot be sufficiently pressed against the insulating seat 116, the acoustic resistance value becomes inappropriate, resulting in a poor directional frequency response.

Further, in the condenser microphone, a means using a ribbon wire has been proposed in order to ensure electrical connection between the fixed pole and the FET (see, for example, Patent Document 4).
However, when electrically connecting a conductive component that draws a signal from the fixed pole and the fixed pole using a contact spring or ribbon wire for electrical connection, it is difficult to assemble because both are small components. Moreover, since the contact part with the said component is small, when there exists a film of fats and oils, an adhesive agent, etc. in a contact part, the contact failure may generate | occur | produce easily.
Japanese Utility Model Publication No.59-76200 Japanese Utility Model Publication No. 63-187500 Japanese Utility Model Publication No. 7-29996 Japanese Utility Model Publication No. 4-50995

The present invention has been made in view of the above circumstances, and uses a condenser microphone unit having a structure that can prevent inconvenience that the damper is displaced in the process of fitting the fixed pole to the insulating seat. An object is to provide a condenser microphone.
Another object of the present invention is to provide a condenser microphone unit capable of reliably connecting the fixed pole and the FET and a condenser microphone using the condenser microphone unit.

  A condenser microphone unit according to a first aspect of the present invention includes a diaphragm, a fixed electrode that is disposed opposite to the diaphragm with a gap between the diaphragm and the diaphragm. An insulating seat that is disposed on the rear surface side of the fixed pole and supports the fixed pole, an annular acoustic resistance member that is disposed on the front surface side of the insulating seat, and an annular shape that presses the acoustic resistance member against the insulating seat from the front surface side The condenser microphone unit including at least the damper is further provided with a fixing member that presses the damper from the front side.

  A condenser microphone unit according to a second aspect of the present invention is the condenser microphone unit according to the first aspect, wherein the fixing member is attached to the insulating seat.

  A condenser microphone unit according to a third aspect of the present invention is the condenser microphone unit according to the first or second aspect, wherein the fixing member presses an inner peripheral edge of the damper.

  A condenser microphone unit according to a fourth aspect of the present invention is the condenser microphone unit according to any one of the first to third aspects, wherein the fixing member has conductivity.

  The condenser microphone unit according to a fifth aspect of the present invention is the condenser microphone unit according to the fourth aspect, wherein the fixing member has a convex portion exposed from a rear surface side of the insulating seat.

  A condenser microphone unit according to a sixth aspect of the present invention is the condenser microphone unit according to any one of the first to fifth aspects, wherein the damper has conductivity.

  A condenser microphone according to a seventh aspect of the present invention includes the condenser microphone unit according to any one of the first to sixth aspects.

According to the condenser microphone unit of the present invention, the fixing member is provided that presses the annular damper from the front side and temporarily fixes the fixed pole before fitting the fixed pole to the insulating seat.
Therefore, the annular acoustic resistance member disposed on the front side of the insulating seat is pressed against the insulating seat by the damper, and the damper is reliably pressed by the fixing member. This reduces the possibility that the damper will be displaced due to an external impact or the like, and the fixed pole is not attached to the insulating seat in an inclined manner. The member can be pressed sufficiently.
Therefore, it is possible to provide a condenser microphone unit having a structure that can prevent the inconvenience of the damper being displaced in the process of fitting the fixed pole to the insulating seat, and a condenser microphone using the condenser microphone unit.

In addition, since the fixing member is attached to the insulating seat, the damper can be reliably supported so as not to be separated from the insulating seat.
Therefore, after the damper is pressed by the fixing member, the effect of pressing the damper against the insulating seat and the effect of preventing the position shift of the damper can be further enhanced.

Moreover, the said fixing member can press the said damper against the said insulation seat, guiding with the said fixing member, pressing the inner periphery part of the said damper.
Therefore, the effect of preventing the displacement of the damper can be further enhanced. In addition, since the dimension in the width direction can be made smaller than that of the damper, the structure is not bulky and the material cost can be reduced.

In addition, since the fixing member has conductivity, the fixing pole and the fixing member can be electrically connected, and the fixing member and the FET can be electrically connected.
Therefore, the electrical connection between the fixed pole and the FET can be effectively and simply and reliably performed together with the prevention of the displacement of the damper via the fixing member.

Further, since the fixing member has a convex portion exposed from the rear surface side of the insulating seat, the fixing member and the FET can be directly electrically connected.
Accordingly, the electrical connection between the fixed member and the FET can be reliably performed, and the electrical connection between the fixed pole and the FET can be enhanced.

Further, since the damper has conductivity, the fixed pole and the damper can be electrically connected, and the damper and the fixing member can be electrically connected.
Therefore, the fixed pole and the fixing member can be more reliably electrically connected via the damper, and the fixed pole and the FET can be more reliably connected.

  By providing the condenser microphone unit according to any one of claims 1 to 6, the sensitivity and frequency response are not deteriorated, and the electrical connection between the fixed electrode and the FET is ensured. A condenser microphone that can be performed can be provided.

Hereinafter, the present invention will be described in detail with reference to the drawings.
FIG. 1 is a longitudinal side view showing an example of a condenser microphone unit according to the present invention, and FIG. 2 is a development view for explaining the structure of main components.
As shown in FIG. 1, the condenser microphone unit 10 of the present embodiment includes at least a diaphragm 13, a fixed pole 15, an insulating seat 16, an acoustic resistance member 17, and a damper 18 in a unit case 11. The fixing member 19 is configured to be assembled and further includes a damper 18 that presses the damper 18 from the front side.

  The unit case 11 has a bottomed cylindrical shape, and a portion corresponding to the bottom portion 11a is on the front side. In addition, a plurality of holes 22 are formed in the bottom portion 11a of the unit case 11 for introducing sound into the unit. The hole 22 may be a so-called front mesh in which the hole 22 is meshed. The unit case 11 can be formed by drawing, for example.

  The outer peripheral edge of the diaphragm 13 is fixed to one end surface of the ring-shaped diaphragm holder 12, and is disposed at a position closest to the bottom of the unit case 11 via a dustproof member 25.

The fixed pole 15 is disposed opposite to the diaphragm 13 via a spacer 14 that is a ring-shaped member. A gap corresponding to the thickness of the spacer 14 is formed between the diaphragm 13 and the fixed electrode 15 to constitute a kind of capacitor. In addition, the fixed pole 15 uses, for example, a metal disk-shaped member as a base material, and an electret plate is attached to at least one surface of the fixed electrode 15 on the surface facing the diaphragm 13 to constitute an electret board. . The spacer 14 is a ring-shaped member made of a thin resin, and is in close contact with the outer peripheral edge of the rear end surface (the lower end surface in FIG. 1) of the diaphragm.
Then, as the diaphragm 13 vibrates according to the sound introduced from the hole 22, the capacitance of the capacitor changes, and the change in capacitance is output as a sound signal.

The insulating seat 16 is a fixed pole support that is disposed on the rear surface side of the fixed pole 15 and supports the fixed pole 15. The insulating seat 16 is made of, for example, an insulator such as a resin, and the outer periphery is cylindrical. Moreover, the circular 1st recessed part 16a is formed in the front side, The said fixed pole 15 has fitted in this 1st recessed part 16a. In addition, a ring-shaped second recessed portion 16b is formed in the first recessed portion 16a on the inner peripheral side with respect to the first recessed portion 16a. The acoustic resistance member 17 and the damper 18 are fitted in the ring-shaped second recessed portion 16b.
Further, a hole 16c is formed in the central portion of the insulating seat 16 in the thickness direction, and the fixing member 19 is fitted into the hole 16c.

The acoustic resistance member 17 controls braking and directivity of the acoustic mechanical system, and is disposed on the front side of the insulating seat 16. The acoustic resistance member 17 has an annular shape.
The acoustic resistance is preferably set such that the acoustic resistance of the acoustic resistance member 17 is 10 times or more that of the damper 18.

The damper 18 is a member that presses the acoustic resistance member 17 against the insulating seat 16 from the front side. The damper 18 has elasticity and has a ring shape.
In addition, since the damper 18 is in contact with the fixed pole 15 and the fixed member 19, it is desirable that the damper 18 be a conductive cloth having conductivity. Thus, when the damper 18 has conductivity, as shown in FIG. 3, an electrical connection is made possible in the α region of the damper 18 in contact with the fixed pole 15. Then, the electrical connection between the fixed pole 15 and the fixed member 19 can be more reliably performed via the damper 18.

The fixing member 19 is a member that presses the damper 18 from the front side. Thereby, the possibility that the damper 18 is displaced is reduced. Therefore, the fixed pole 15 is not attached to the insulating seat 16 in an inclined manner, and the acoustic resistance member 17 can be sufficiently pressed against the insulating seat 16.
The fixing member 19 is preferably attached to the insulating seat 16. When the fixing member 19 is attached to the insulating seat 16 in this way, the damper 18 can be reliably supported so as not to be separated from the insulating seat 16 without darkness. The effect of pressing the damper 18 against the insulating seat 16 and the effect of preventing the displacement of the damper 18 can be further enhanced.

Further, it is desirable that the fixing member 19 presses the inner peripheral edge of the damper 18 as in the illustrated example. The place where the damper 18 is pressed may be at least a part instead of the entire inner peripheral edge. The fixing member 19 is preferably formed with, for example, a flange portion 19a that protrudes outward at the peripheral edge of the upper end. Then, the inner peripheral edge portion of the damper 18 can be pressed by the flange portion 19 a of the fixing member 19.
When the inner periphery of the damper 18 is pressed by the flange 19a in this way, the damper 18 is guided by the flange 19a while the damper 18 is guided by the fixing member 19, as shown in FIG. Hold the inner edge. The acoustic resistance member 17 can be sufficiently pressed against the insulating seat 16 by the damper 18.

The fixing member 19 is in contact with the fixed pole 15 and a field effect transistor (hereinafter referred to as “FET”) 20 described later. Therefore, it is desirable that the fixing member 19 is made of a conductive metal material such as copper or stainless steel, or a conductive resin material mixed with a conductive material. When the fixing member 19 is conductive in this way, as shown in FIG. 3, electrical connection is enabled in the β region of the fixing member 19 that is in contact with the fixed pole 15. Then, the electrical connection between the fixed electrode 15 and the FET 20 can be more reliably performed through the fixed member 19.
Therefore, the fixing member 19 can effectively, easily and reliably make the electrical connection between the fixed pole 15 and the FET 20 in addition to preventing the displacement of the damper 18.

  Furthermore, it is preferable that the fixing member 19 has a convex portion 19 b exposed from the rear surface side of the insulating seat 16. Thus, when the fixing member 19 has the convex portion 19b, the convex portion 19b can be fitted into the hole 16c formed in the central portion of the insulating seat 16, as shown in FIG. Then, the convex portion 19b is exposed from the rear surface side of the insulating seat 16, and the fixing member 19 can be easily and directly connected to the FET 20 and can be reliably connected.

Further, a disc-shaped printed circuit board 21 is disposed on the rear surface side of the insulating seat 16, and the insulating seat 16 and the printed circuit board 21 are in contact with each other at the outer peripheral edge portion.
On the outer peripheral edge of the rear surface of the printed circuit board 21, the folded portion 23 of the open end edge of the unit case 11 is located. The printed circuit board 21 is pushed forward (upward in FIG. 1) by the pressing force of the folded portion 23. In addition, the insulating seat 16 is pushed by this pushing force, and the fixed pole 15 is pushed through the damper 18. Further, the diaphragm 13 and the diaphragm holder 12 are pressed against the bottom surface 11 a of the unit case 11 through the spacer 14. Therefore, these members are respectively positioned and fixed in the unit case 11.

  On the printed circuit board 21, an FET 20 constituting an impedance converter is disposed at a position facing the fixing member 19. A part of the terminal 20 a of the FET 20 is bent along the exterior of the FET 20 and is in contact with the lower surface convex portion 19 b of the fixing member 19. That is, the fixing member 19 is pressed against one terminal 20a of the FET 20 by being fitted into a hole 16c formed in the central portion of the insulating seat 16, and electrical connection between the terminal 20a and the fixed pole 15 is achieved. I'm taking it. On the other hand, the other terminal 20b of the FET 20 is connected to a predetermined circuit pattern of the printed circuit board 21 by soldering or the like.

The condenser microphone unit 10 described above has a structure that can prevent inconvenience that the damper 18 is displaced by using the fixing member 19. As a result, the acoustic resistance member 17 is sufficiently pressed against the insulating seat 16 to realize a stable and stable acoustic resistance.
Therefore, when assembling the condenser microphone unit 10, the acoustic resistance member 17 and then the damper 18 are placed on the insulating seat 16, and then the damper 18 is temporarily fixed by the fixing member 19. Then, the fixed electrode 15 is press-fitted into the insulating seat 16 to fit them together. As a result, the damper 18 is sandwiched between the fixed pole 15 and the insulating seat 16 while maintaining a correct posture without being inclined, and a stable pressure can be applied to the acoustic resistance member 17. Moreover, the unit price for the fixing member 19 is low, and the assembly process of the condenser microphone unit 10 can be facilitated.

  In addition, by incorporating a condenser microphone unit with such a structure into a microphone case equipped with a windshield, a condenser microphone that does not cause poor sensitivity and frequency response, and the electrical connection between the fixed pole and the FET A condenser microphone that can be reliably connected can be provided.

It is a vertical side view which shows simply an example of the condenser microphone unit concerning the present invention. It is an exploded view explaining the structure of the main components of the condenser microphone unit shown in FIG. It is a vertical side view explaining the electrical connection situation of a fixed pole, a fixing member, and a damper. It is a vertical side view explaining how to hold down a damper by a fixing member. It is a vertical side view which shows an example of the conventional capacitor | condenser microphone unit simply. It is a vertical side view which shows an example of the conventional capacitor | condenser microphone unit simply.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Condenser microphone unit 11 Unit case 12 Diaphragm holder 13 Diaphragm 14 Spacer 15 Fixed pole 16 Insulation seat 17 Acoustic resistance member 18 Damper 19 Fixed member 20 Field effect transistor (FET)
21 printed circuit boards

Claims (7)

In the unit case,
A diaphragm,
A fixed pole that is disposed opposite to the diaphragm with a gap, and constitutes a capacitor with the diaphragm,
An insulating seat disposed on the rear surface side of the fixed pole and supporting the fixed pole;
An annular acoustic resistance member disposed on the front side of the insulating seat;
An annular damper that presses the acoustic resistance member against the insulating seat from the front side;
In a condenser microphone unit configured to incorporate at least
A condenser microphone unit, further comprising a fixing member for pressing the damper from the front side.   The condenser microphone unit according to claim 1, wherein the fixing member is attached to the insulating seat.   The condenser microphone unit according to claim 1, wherein the fixing member presses an inner peripheral edge of the damper.   The condenser microphone unit according to claim 1, wherein the fixing member has conductivity.   The condenser microphone unit according to claim 4, wherein the fixing member has a convex portion exposed from a rear surface side of the insulating seat.   The condenser microphone unit according to claim 1, wherein the damper has conductivity.   A condenser microphone comprising the condenser microphone unit according to any one of claims 1 to 6.

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