JP2001008293A - Condenser microphone - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a condenser microphone with for part items and higher sensitivity, in comparison with a conventional condenser microphone. SOLUTION: A diaphragm 24, a rear electrode 26, and a terminal board 31 on which an IC element 33 consisting of a microphone use FET is mounted are contained, in a casing 20 whose top face has sound holes in this order from the top face while keeping a prescribed interval, a contact ring 30 in common use of a spacer made of a conductive material is interposed between a rear face of the rear electrode 26 and the front side of the terminal board, a spacer ring 29 of an insulation material 27 integrated with an insulation cylinder 28 along with an inner circumferential face of the casing 20 and the spacer ring 29 projected integrally in the inner side of the top is interposed between the diaphragm 24 and the rear electrode 26, and the insulation cylinder 28 insulates the rear electrode 26, the contact ring 30 and the casing 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a condenser microphone such as an electret condenser microphone.

[0002]

2. Description of the Related Art Conventionally, as a condenser microphone, as shown in FIGS. 4 and 5, a bottom plate of an aluminum casing 1 having a bottomed cylindrical shape is used as a top plate, and a sound hole is formed in the top plate 2. A diaphragm 5, a spacer 6, a spacer 6, a back electrode 7, an insulating spacer tube 8, and a terminal substrate 9 are stacked and housed in this order in order, and the skirt 10 of the casing 1 is accommodated therein. It is assembled so that it cannot be pulled out by bending inward and caulking, and an FET (field effect transistor) is provided on the surface of the terminal board 9.
Is fixed, and the cylindrical contact ring 12 is fixed to the back electrode 7 along the inner surface of the insulating spacer tube 8.
And a wiring (not shown) on the surface of the terminal board 9.

[0003]

In such a conventional condenser microphone, the insulation of the back electrode 7 with respect to the casing and the maintenance of the space for forming the back electrode back space are held by the insulating spacer tube 8. For
A large spacer cylinder 8 is required between the diaphragm 5 and the back electrode 7, and the space behind the back electrode has to be narrowed, and there is a problem that the maintenance and the increase of the sensitivity are limited. Further, the spacer 6 and the insulating spacer tube 8 are required as separate parts, and there is a problem that the number of parts increases.

The present invention has been made in view of such a conventional problem,
The object of the present invention is to provide a condenser microphone that can have higher sensitivity and a smaller number of components than conventional products.

[0005]

SUMMARY OF THE INVENTION The features of the present invention for solving the conventional problems as described above and achieving the intended purpose are as follows.
A condenser microphone in which a terminal board to which an IC element composed of a diaphragm, a back electrode, and a microphone FET is fixed in a casing having a sound hole in a top plate in order from the top surface side while maintaining a predetermined interval. In the above, a contact ring also serving as a spacer made of a conductive material is interposed between the back surface of the back electrode and the surface of the terminal substrate, and an insulating film is interposed between the outer peripheral surface of the contact ring and the inner peripheral surface of the casing for insulation. I did it.

The insulating film is made of an insulating material integrally having an insulating cylindrical portion along the inner peripheral surface of the casing and a spacer ring portion integrally protruding inside the top of the insulating cylindrical portion. Is preferably interposed between the diaphragm and the back electrode, and the insulating cylinder is used to insulate the back electrode and the contact ring from the casing. In this case, the conventional spacer cylinder is eliminated and the spacer ring is removed. The number of parts can be reduced because the part and the insulating cylinder are configured as one part.

The insulating film may be constituted by an insulating film adhered to the inner surface of the casing.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the present invention will be described with reference to FIGS.

In FIG. 1, reference numeral 20 denotes an aluminum casing. The casing 20 is formed into a bottomed cylindrical shape by drawing, and its bottom wall is used as a top plate 21.
A sound hole 22 is opened in this. Casing hem 2
Numeral 3 is bent inward and crimped to prevent the below-described members housed therein from coming off.

A diaphragm 24 is accommodated in the casing 20 below the top plate 21 at an interval. Diaphragm 24
Is fitted to the inside of the casing 20 and is fixed to a circular diaphragm ring 25 in contact with the inner surface of the top plate 21.
The diaphragm ring 25 maintains the distance from the top plate 21.

A back electrode 26 is accommodated below the diaphragm 24 at a distance therefrom. The back electrode 26 is housed in a cylindrical insulating material 27 inserted in contact with the inner surface of the casing 20, and the back electrode 26 and the casing 20 are insulated. The insulating member 27 is composed of an insulating cylindrical portion 28 formed in a cylindrical shape and a circular ring-shaped spacer ring portion 29 integrally formed on the inside of the top portion thereof. The gap between the diaphragm and the back electrode 26 is provided between the diaphragm 24 and the back electrode 26.

The lower end of the back electrode 26 is in contact with the upper end of a cylindrical contact ring 30, and the lower end of the contact ring is in contact with and overlaps a terminal board 31. Hem is crimped. The contact ring 30 and the casing 20 are insulated by an insulating tubular portion 28 of an insulating material 27.

The inside of the contact ring 30 is the back electrode back space 3.
2, an IC element 33 composed of an FTT (field effect transistor) and a chip capacitor 34 are accommodated in the upper surface of the terminal substrate 31, and the contact ring 30 is connected to the back electrode 26 and the terminal substrate 31.
And also serves as a spacer between them.

In the condenser microphone thus configured, the diaphragm 24 and the back electrode 26 face each other by the spacer ring portion 29, an electric capacitor is formed, and the sound that enters through the sound hole 22 by transmitting air. The vibration of the diaphragm 24 is caused by the vibration of the diaphragm 24, and the movement of the diaphragm 24 is controlled by the moderate compliance of the diaphragm 24 itself and the air in a slight gap between the diaphragm 24 and the back electrode 26 formed by the spacer ring portion 29. The vibration plate 2 is controlled by a suitable viscous resistance and a compliance of a back electrode back space 32 of an appropriate size communicating with a pore 34 opened to the back electrode 26.
A slight change in the distance from the back electrode 26 due to the vibration of 4 causes a change in the voltage across the formed capacitor, and this change is converted into a low impedance by the IC element 33 fixed on the terminal board 31, and Output.

In the above-described example, the insulating material 27 is used, which has the insulating cylinder portion 28 and the spacer ring portion 29 integrally protruding inside the top of the insulating cylinder portion.
As shown in FIG.
0 may be interposed between the vibrating plate 24 and the back electrode 26, and the insulating film 41 may be interposed between the back electrode 26 and the contact ring 30 and the casing 20 by being attached to the inner surface of the casing 20. . As described above, the use of the insulating film 41 facilitates manufacturing. The same parts as those in the examples shown in FIGS. 1 and 2 are denoted by the same reference numerals, and redundant description will be omitted.

[0016]

As described above, in the condenser microphone according to the present invention, the contact ring, which also serves as a spacer, made of a conductive material is interposed between the back surface of the back electrode and the surface of the terminal board. Insulation between the inner surface of the casing and the inner surface of the casing is achieved by interposing an insulating film, which eliminates the need for the spacer ring made of insulating material used in conventional condenser microphones of this type. The back space is large, and a highly sensitive product can be obtained with the same size casing as the conventional product.Moreover, the back electrode back space is large, so when soldering the electrodes of the chip capacitor to the board This eliminates the risk of short-circuiting with the contact ring due to the flow of solder material, and also allows the incorporation of multiple chip capacitors, improving sensitivity. It can be achieved without increasing the shape shape.

Further, the insulating film is constituted by an insulating material integrally having an insulating cylindrical portion along the inner peripheral surface of the casing and a spacer ring portion integrally protruding inside the top of the insulating cylindrical portion. Is interposed between the diaphragm and the back electrode, and the insulation between the back electrode and the contact ring and the casing is insulated by the insulating cylinder, thereby reducing the number of parts and reducing the cost. is there.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an example of a condenser microphone according to the present invention.

FIG. 2 is a cross-sectional view of the same.

FIG. 3 is a longitudinal sectional view of another example of the condenser microphone according to the present invention.

FIG. 4 is a longitudinal sectional view of a conventional condenser microphone.

FIG. 5 is a cross-sectional view of the same.

[Explanation of symbols]

 REFERENCE SIGNS LIST 20 casing 21 top plate 22 sound hole 23 skirt portion 24 diaphragm 25 diaphragm plate ring 26 back electrode 27 insulating material 28 insulating tube portion 29 spacer ring portion 30 contact ring 31 terminal board 32 back electrode back space 33 IC element 34 chip capacitor 40 Spacer ring 41 Insulation coating

Claims (3)

[Claims] 1. A diaphragm, a back electrode, and a microphone F in a casing having a sound hole in a top plate in order from the top surface side.
In a condenser microphone in which a terminal board to which an IC element made of ET is fixed and maintained at a predetermined interval is provided, a contact ring also serving as a spacer made of a conductive material is interposed between the back surface of the back electrode and the surface of the terminal board. A condenser microphone, characterized in that an insulating film is interposed between the outer peripheral surface of the contact ring and the inner peripheral surface of the casing to insulate the contact ring. 2. An insulating film comprising an insulating material integrally having an insulating cylindrical portion along an inner peripheral surface of a casing and a spacer ring portion integrally protruding inside a top portion of the insulating cylindrical portion,
2. The condenser microphone according to claim 1, wherein the spacer ring is interposed between the diaphragm and the back electrode, and the back electrode and the contact ring are insulated from the casing by an insulating cylinder. 3. The condenser microphone according to claim 1, wherein the insulating film comprises an insulating film attached to an inner surface of the casing.