JP5377997B2 - Unidirectional condenser microphone unit and unidirectional condenser microphone - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique for stabilizing acoustic resistance of unidirectional condenser microphones. <P>SOLUTION: A condenser microphone unit at least includes, in a unit case 10, a diaphragm 13, a fixed pole 15 that is oppositely disposed in the diaphragm 13 at an interval and composes a capacitor between the diaphragm 13, an insulation seat 16 that is disposed at a rear face side of the fixed pole 15 and supports the fixed pole 15, an annular acoustic resistance member 17 disposed at a front face side of the insulation seat 16, an annular damper 18 pressing the acoustic resistance member against the insulation seat 16 from the front face side, and a fixing member 19 holding down the damper 18 from the front face side. The insulation seat 16 includes a projection for pressing the acoustic resistance member 17. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a condenser microphone unit and a condenser microphone, and more particularly to a technique for stabilizing the acoustic resistance of a unidirectional condenser microphone.

  A condenser microphone is a condenser microphone 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 arranged opposite to each other via a spacer, and the capacitance changes due to vibration of the diaphragm With units. This condenser microphone unit is assembled in a unit case.

  In such a condenser microphone, there are mainly the following two methods for forming an acoustic resistance that gives the desired directivity by limiting or controlling the sound wave guided to the diaphragm. 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 the directional condenser microphone unit as shown in FIG. 4, the sound wave taken from the rear acoustic terminal A is divided by the impedance of the air chamber formed by the acoustic resistance member 117 and the damper 118, and the rear part of the diaphragm Unidirectionality is gained by adding to.

  In FIG. 4, the condenser microphone unit 110 is configured by housing the following components 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 holding body 112 and a diaphragm 113 having an outer peripheral edge fixed to one end surface of the diaphragm holding body are located at a position closest to the bottom 111a of the unit case 111. Has been placed.

  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, and the diaphragm 113 and the fixed electrode 115 constitute a kind of capacitor. As the diaphragm 113 vibrates in accordance with the sound introduced from the hole 122, the capacitance of the capacitor changes, and the change in capacitance is output as an audio 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 hole is formed in the central portion of the insulating seat 116 in the thickness direction, and a terminal member 119 is fitted into the hole, and the terminal member 119 is electrically connected to an FET (not shown). .

  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. The spacer 114 is overlaid on the fixed pole 115, and the diaphragm 113 integral with the diaphragm holder 112 is overlaid thereon, and the bottomed cylindrical unit case 111 is placed on the outer periphery of each of these built-in components. The open end portion of the unit case 111 is bent inward, and the built-in components are pressed toward the bottom portion 111 a of the unit case 111 by the pressing force of the bent portions, and the built-in components are fixed in the unit case 111. 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, 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 position of the damper 118 is shifted in the process of fitting the fixed electrode 115 to the insulating seat 116. There is an inconvenience. As a result, the peripheral portion 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.

In view of this, in the condenser microphone unit as described above, means is further proposed that further includes a fixing member that presses the damper from the front side (see, for example, Patent Document 4). In addition, there has been proposed a condenser microphone in which a flange extending in the circumferential direction is formed in a cylindrical case, and an acoustic resistance assembly and a back plate are fixed to both end faces of the flange. (For example, refer to Patent Document 5).
According to the invention described in Patent Document 4, the fixing member has a structure in which the center portion of the damper is pressed down in a concentrated manner. Therefore, the acoustic resistance member is not sufficiently pressed at the periphery of the damper, and the desired acoustic resistance is obtained. Difficult to get.
Further, according to the invention described in Patent Document 5, the configuration of the rear acoustic resistor is extremely complicated, and the microphone unit becomes long and bulky in the central axis direction.

Japanese Utility Model Publication No.59-76200 Japanese Utility Model Publication No. 63-187500 Japanese Utility Model Publication No. 7-29996 JP 2008-177967 A JP-A-5-7398

  The present invention has been made in view of the above circumstances, and is a condenser microphone unit having a structure in which the acoustic resistance material is pressed with a sponge or the like, and a portion other than the opening constituting the rear acoustic terminal, for example, an insulating seat An object of the present invention is to provide a condenser microphone unit and a condenser microphone that can prevent a sound wave from leaking sideways from a gap between the acoustic resistance material and the acoustic resistance material with a simple configuration and obtain a stable acoustic resistance as expected. .

The present invention relates to a unidirectional condenser microphone unit, which is disposed in a unit case so as to face a diaphragm and a gap between the diaphragm and to form a capacitor between the diaphragm and the diaphragm. An insulating seat that supports the fixed pole that is disposed on a rear surface side of the fixed pole and that has an opening that forms a rear acoustic terminal; and a rear surface side of the fixed pole and a front side of the insulating seat An opening that constitutes the rear acoustic terminal has an elastic annular damper that is disposed between, and an annular acoustic resistance member that is disposed between the front side of the insulating seat and the damper. Note that a plurality of formed, around the acoustic resistance member side of the opening, the convex portion which projects along the periphery of each opening be formed, each of the convex portions, said damper and said acoustic resistance member It is pressed against the More prevent the gap between the insulation cylinder and the acoustic resistance member, and, through the acoustic resistance member is deformed the damper, preventing the displacement of the damper with respect to the fixed electrode and the insulation cylinder, most major that Features.

  According to the condenser microphone unit of the present invention, in the condenser microphone unit having a structure for pressing the acoustic resistance material, the acoustic resistance material is pressed by the convex portion around the opening of the insulating material, for example, the insulating seat and the acoustic resistance material It is possible to provide a condenser microphone unit having a structure in which acoustic waves are prevented from lateral leakage from a path through which sound waves pass, such as a gap between them, and acoustic resistance is stabilized.

It is a longitudinal cross-sectional view which shows simply the Example of the condenser microphone unit which concerns on this invention. It is a front view which shows the insulating seat in the said Example. It is a front view which shows the modification of the insulating seat applicable to this invention. It is a longitudinal cross-sectional view which shows an example of the conventional condenser microphone unit simply.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a longitudinal side view showing an embodiment of a condenser microphone unit of the present invention, which is an example of a unidirectional microphone unit.
In FIG. 1, a unitary condenser microphone unit 10 is configured by incorporating components such as 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. Yes. The unit case 11 has a front portion corresponding to the bottom, and a plurality of holes 22 for introducing sound into the unit are formed in the bottom. These holes constitute the front acoustic terminals. In the unit case 11, a ring-shaped diaphragm holding body 12 and a diaphragm 13 having an outer peripheral edge fixed to one end surface of the diaphragm holding body 12 are disposed at a position closest to the bottom of the unit case 11. Has been.

  A fixed pole 15 is disposed opposite to the diaphragm 13 via a spacer 14 which is a ring-shaped member. A gap corresponding to the thickness of the spacer 14 is formed between the diaphragm 13 and the fixed pole 15, and the diaphragm 13 and the fixed pole 15 constitute a kind of capacitor. As the diaphragm 13 vibrates according to the sound introduced from the front acoustic terminal, the capacitance of the capacitor changes, and the change in capacitance is output as an audio signal. Yes.

  In the unit case 11, an insulating seat 16 that is a fixed pole support is disposed on the rear surface side of the fixed pole 15. The insulating seat 16 is made of, for example, synthetic resin, and a circular recess is formed on the front side thereof. The fixed pole 15 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 17 and the elastic damper 18 are fitted into the ring-shaped concave portion. It has been. A hole is formed in the central portion of the insulating seat 16 in the thickness direction, and a terminal member 19 is fitted into the hole, and the terminal member 19 is electrically connected to an FET (not shown). .

  The configuration described so far is substantially the same as the configuration of the conventional example shown in FIG. Next, a characteristic configuration of the present invention will be described. In FIG. 1 and FIG. 2, the insulating seat 16 is disposed on the rear surface side of the fixed pole 15 and serves as a fixed pole support for supporting the fixed pole 15. The insulating seat 16 has a plurality of openings 16d that function as rear acoustic terminals. The opening 16d is formed through the insulating seat 16 in the thickness direction. On the front side of the insulating seat 16, an annular convex portion 16 e for pressing the acoustic resistance member 17 toward the damper 18 is provided around each opening 16 d.

  The insulating seat 16 may be replaced with the one shown in FIG. 3 instead of the one shown in FIG. The insulating seat 16 shown in FIG. 3 has a plurality of openings 16d arranged concentrically on the outer side in the radial direction of the insulating seat 16 instead of forming convex portions 16e around each opening 16d that functions as a rear acoustic terminal. In accordance with the inner side, each opening 16d is sandwiched between the two convex portions 16f inside and outside in the radial direction. The acoustic resistance member 17 can be pressed toward the damper 18 by these convex portions 16f, and the lateral leakage of the sound wave from the gap of the acoustic resistance material 17 can be prevented.

  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. The first concave portion 16a is formed with a ring-shaped second concave portion 16b on the inner peripheral side of the first concave 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 in 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 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. Further, since the damper 18 is in contact with the fixed electrode 15, it is preferable to use a conductive cloth having conductivity.

  The terminal member 19 is fitted in the hole 16c of the insulating seat. The terminal member 19 is in contact with the fixed pole 15 and a field effect transistor (hereinafter referred to as “FET”) (not shown). Therefore, the terminal member 19 is preferably made of a conductive metal material such as copper or stainless steel or a conductive resin material mixed with a conductive material.

  The above has described the condenser microphone according to the present invention based on the illustrated embodiment, and the specific configuration thereof is not limited to this. For example, the shape and size of the capacitor unit are not limited, and the cross-sectional shape of the opening 16d of the insulating seat 16 is arbitrary and does not necessarily have to be a perfect circle. The protrusion 16e of the insulating seat 16 is not limited to the periphery of the opening 16d as long as it can press the acoustic resistance member 17 and the damper 18.

The condenser microphone unit described above can be configured as a condenser microphone by incorporating it into a microphone case and incorporating other necessary components such as a circuit board and a connector.
The illustrated embodiment is an example of a unidirectional condenser microphone unit and a condenser microphone. However, the present invention is not limited to this, and a condenser microphone unit including a rear acoustic terminal and an acoustic resistance member covering the rear acoustic terminal. Any condenser microphone can be applied.

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

Claims (4)

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 for supporting the fixed pole, which is disposed on the rear surface side of the fixed pole and has an opening forming a rear acoustic terminal;
An annular damper having elasticity disposed between the rear surface side of the fixed pole and the front surface side of the insulating seat;
An annular acoustic resistance member disposed between the front side of the insulating seat and the damper;
A plurality of openings constituting the rear acoustic terminal are formed,
On the periphery of the opening on the acoustic resistance member side, a convex portion that protrudes along the periphery of each opening is formed,
Each convex portion prevents the gap between the insulating seat and the acoustic resistance member by pressing the acoustic resistance member toward the damper, and deforms the damper via the acoustic resistance member, Prevent the damper from being displaced relative to the fixed pole and the insulating seat,
Unidirectional condenser microphone unit characterized by that . Rear opening constituting the acoustic terminal is formed in plural on a concentric circle, the convex portion of the insulation cylinder is unidirectional condenser microphone unit according to claim 1, wherein is protruded so as to sandwich the respective opening in the radial direction and out. Said damper, unidirectional condenser microphone unit according to claim 1 or 2, characterized in that electrically conductive. A unidirectional condenser microphone comprising the condenser microphone unit according to any one of claims 1 to 3 .

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