JP4726748B2 - Condenser microphone unit and condenser microphone - Google Patents

Description

  The present invention relates to a condenser microphone unit and a condenser microphone that have been devised to prevent vibration noise.

  A conventional example of a condenser microphone unit is shown in FIGS. 3 and 4, reference numeral 1 denotes a case of a condenser microphone unit, that is, a unit case. The unit case 1 has a bottomed cylindrical shape, and a portion corresponding to the bottom portion is a front side, and a hole 1a for introducing sound into the condenser microphone unit is formed in the bottom portion. In the unit case 1, a ring-shaped diaphragm holder 2 is disposed at a position closest to the bottom of the unit case 1, and an outer peripheral edge is fixed to one end surface of the diaphragm holder 2 by bonding or the like. A diaphragm-like diaphragm 3 is disposed.

  A fixed pole 5 is disposed opposite to the diaphragm 3 with a spacer 4 interposed. The spacer 4 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 (lower end surface in FIG. 3) of the diaphragm 3. A gap corresponding to the thickness of the spacer 4 is formed between the diaphragm 3 and the fixed pole 5. The fixed pole 5 uses a metal disc as a base material, and an electret plate is attached to at least one side thereof, for example, the side facing the diaphragm 3 to constitute an electret board. The diaphragm 3 and the fixed pole 5 constitute a kind of capacitor. As the diaphragm 3 vibrates according to the sound introduced from the hole 1a, the capacitance of the capacitor changes, and electrostatic The change in capacity is output as an audio signal.

  An insulating sleeve 6 made of an insulating material that defines the radial dimension of the fixed pole 5 is disposed in the unit case 1. A conductive sleeve 7 made of a conductive material is disposed in contact with the inner peripheral surface of the insulating sleeve 6. The rear end surface portion of the conductive sleeve 7 is in contact with a circuit pattern 8a (see FIG. 4) formed on the disk-shaped printed circuit board 8, and the rear end surface peripheral portion of the printed circuit board 8 is at the open end of the unit case 1. The folded portion 10 at the edge is in contact. The conductive sleeve 7 is pushed upward by the pressing force generated when the folded portion 10 pushes the printed board 8 forward (upward in FIG. 3), and the diaphragm holder 4 is further moved to the unit case via the spacer 4. These members are positioned and fixed in the unit case 1 by being pressed against the bottom surface of the unit 1. The conductive sleeve 7 electrically connects the fixed pole 5 and the printed board 8.

  A field effect transistor (hereinafter referred to as “FET”) 9 constituting an impedance converter is disposed on the printed circuit board 8. Some terminals of the FET 9 are connected to a predetermined circuit pattern 8a of the printed circuit board 8 by soldering or the like.

  In the above-described unit, the folded portion 10 that functions to apply pressure so that each member is fixed in the unit case 1 is generated by plastically deforming the rear end edge portion of the unit case 1 by a caulking process. The Many units having such a structure are known (see, for example, Patent Document 1).

Japanese Patent Application Laid-Open No. 2002-354592

  The aforementioned unit case 1 is usually generated by press working. Therefore, there is variation in the height before the caulking process. Therefore, it is difficult for the upward pressing force generated by the folding portion 10 generated by the caulking process to be applied uniformly, and the positioning of the members in the unit case is likely to vary. When the position of the member varies, the force (pushing pressure) for fixing the fixed pole 5 and the diaphragm 3 also varies, and in particular, the inner peripheral portion of the diaphragm holder 2 that fixes the diaphragm 3. The diaphragm holder 2 may be deformed by internal stress applied to the outer peripheral portion. When the diaphragm holder 2 is deformed, the tension of the diaphragm 3 changes. In particular, when a strong stress is applied to the outer periphery of the diaphragm holder 3, the change in the tension of the diaphragm 3 increases, resulting in performance variations in unit sensitivity and frequency response.

  The insulating sleeve 6 serves to prevent the fixed pole 5 and the conductive sleeve 7 from being eccentric. If the degree of fitting between the insulating sleeve 6 and the fixed pole 5 and the conductive sleeve 7 is weak, a unit is provided. If vibration is applied to the, it will move easily and cause abnormal noise.

  The present invention has been made in view of the above problems, and prevents changes in the tension of the diaphragm due to internal stress applied to the inner and outer peripheries of the diaphragm holder, and abnormal noise is generated even when vibration is applied to the unit. An object of the present invention is to provide a condenser microphone unit and a condenser microphone that can be prevented from occurring.

The present invention provides a condenser microphone unit, a diaphragm, a diaphragm holder to which the diaphragm is fixed, and a fixed pole that is disposed opposite to the diaphragm with a gap therebetween and constitutes a capacitor. And a printed circuit board on which the impedance converter is disposed, and a unit case in which these members are incorporated . An insulating first ring is provided on the inner peripheral surface of the unit case. A conductive second ring is disposed on the inner peripheral surface, and the unit case is a bottomed cylindrical member, and the printed circuit board is pushed by the bent portion by bending the open end of the unit case. , the diaphragm, the diaphragm holding body, the fixed electrode, the internal components comprising the first ring and the second ring is positioned, said first ring and said second Li A resilient conductive biasing member is interposed between the printed circuit board and the printed circuit board, and the second ring has a larger area than the area where the first ring contacts the conductive biasing member. The area contacting the conductive urging member is large, and the pressure due to the elastic force of the urging member applied to the vibrating body holding plate via the second ring and the fixed pole causes the pressure through the first ring. The main feature is that the pressure is greater than the pressure by the elasticity of the urging member applied to the vibrating body holding plate .

According to the present invention, the pressure of the fixing applied to the inner peripheral portion of the diaphragm holding member, can be made larger than pressure applied to the outer peripheral portion, also, even if weak fitting degree of inner component, Since positioning can be performed reliably, it is possible to prevent the generation of abnormal noise due to external forces such as vibration.

Hereinafter, embodiments of a microphone unit according to the present invention will be described with reference to the drawings. The same components as those of the conventional example shown in FIGS. 3 and 4 are denoted by the same reference numerals, and redundant description is avoided as much as possible. FIG. 1 is a sectional view showing an embodiment of a microphone unit according to the present invention. In Figure 1, the insulating sleeve 6 and conductive sleeve 7, between the printed board 8, an annular conductive ring 11 is disposed. The conductive ring 11 is made of elastic conductive rubber or the like, and receives pressure from below by the folded portion 10 of the unit case 1 to transmit the pressure to the insulating sleeve 6 and the conductive sleeve 7. The insulating sleeve 6 is a first ring, and the conductive sleeve is a second ring.

  The conductive ring 11 has a lower end surface in contact with the circuit pattern 8 a on the printed circuit board 8 and an upper end surface in contact with the conductive sleeve to electrically connect the fixed electrode 5 and the printed circuit board 8.

  The conductive sleeve 7 has a bent portion 7a formed by bending the lowermost end portion thereof at a substantially right angle with respect to the inside of the unit so that the conductive sleeve 11 can be reliably contacted. The insulating sleeve 6 is formed with a stepped portion 6a by cutting the inner peripheral surface of the lowermost end portion in the outer peripheral direction in order to ensure the positioning of the conductive ring. The corners on the outer peripheral side of the conductive ring 11 are in contact with the stepped portion 6a.

  When the area where the bent portion 7a contacts the conductive ring 11 is Sb and the area where the circumferential surface of the stepped portion 6a contacts the conductive ring 11 is Ss, the relationship Sb> Ss is established. Determine the dimensions. As a result, when the pressure through the insulating sleeve 6 is Fs and the pressure through the conductive sleeve 7 is Fb, the relationship between the pressing force by the folded portion 10 and the elastic force of the conductive ring 11 is Fb. , Fs <Fb.

Accordingly, the downward pressure applied to the diaphragm holder 2 via the conductive sleeve 7 and the fixed pole 5 is larger than the downward pressure applied to the diaphragm holder 2 via the insulating sleeve 6. That is, even if stress is applied to the outer peripheral portion of the diaphragm holding body 2 due to the pressing force of the turn-back portion 10, the pressure on the inner peripheral portion of the diaphragm holding body 2 is higher. It is possible to prevent deformation of the inner peripheral portion of the holding body 2 and to prevent a change in tension of the diaphragm 2.

  In addition, since the pressure via the elastic force of the conductive ring 11 is more reliably applied to the insulating sleeve 6, it is possible to prevent the generation of abnormal noise that occurs when the unit vibrates.

  As described above, the conductive ring 11 is provided on the contact surface with the printed circuit board 8 in order to more securely and well-balance the members inside the unit, thereby preventing performance deterioration due to changes in the tension of the diaphragm. Further, it is possible to prevent the generation of abnormal noise caused by the movement of the internal member due to vibration or the like.

  The condenser microphone unit according to the embodiment described above can be configured as a condenser microphone by incorporating it into a microphone case.

It is a longitudinal cross-sectional view which shows the Example of the condenser microphone unit which concerns on this invention. It is a top view which shows the example of the circuit board inside the capacitor | condenser microphone unit based on this invention. It is a longitudinal cross-sectional view which shows the Example of the conventional capacitor | condenser microphone unit. It is a top view which shows the example of the circuit board inside the conventional condenser microphone unit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Unit case 2 Diaphragm holder 3 Diaphragm 4 Spacer 5 Fixed pole 6 Insulation sleeve 6a Notch part 7 Conductive sleeve 7a Folding part 8 Printed circuit board 9 FET
10 Folded part 11 Conductive ring

Claims (3)

A diaphragm, a diaphragm holder to which the diaphragm is fixed, a fixed pole that is disposed opposite to the diaphragm with a gap therebetween and constitutes a capacitor, and a print in which an impedance converter is disposed Comprising a substrate and a unit case in which these members are incorporated;
An insulating first ring is disposed on the inner peripheral surface of the unit case, and a conductive second ring is disposed on the inner peripheral surface of the first ring.
The unit case is a cylindrical member with a bottom, and the printed circuit board is pushed by the bent portion by bending the open end of the unit case, so that the diaphragm, the diaphragm holder, the fixed pole , The internal components including the first ring and the second ring are positioned;
Between the first ring and the second ring and the printed circuit board, an elastic conductive biasing member is interposed,
The area where the second ring contacts the conductive urging member is larger than the area where the first ring contacts the conductive urging member,
The pressure generated by the elastic force of the biasing member applied to the vibrating body holding plate via the second ring and the fixed pole is the pressure generated by the elastic force of the biasing member applied to the vibrating body holding plate via the first ring. Capacitor microphone unit characterized by being larger than . In the vicinity of the open end of the unit case,
A stepped portion formed by cutting the end surface of the inner periphery of the first ring;
A bent portion formed by bending the end surface of the second ring to the inner peripheral side of the unit case,
The condenser microphone unit according to claim 1, wherein the urging member is disposed so as to contact the stepped portion and the bent portion . Condenser microphone unit is a condenser microphone comprising integrated into the microphone case, the condenser microphone is a condenser microphone unit is a condenser microphone unit according to claim 1 or 2.