JP2607288Y2 - Microphone unit mounting structure - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mounting structure of a microphone unit to a housing, and more particularly, to a mounting of a microphone unit which can be reliably connected to an earth pattern simply by press-fitting the microphone unit into the housing. Regarding the structure.

[0002]

2. Description of the Related Art A condenser microphone unit in which a change in capacitance between a diaphragm and a back electrode, which is a fixed electrode located behind the diaphragm , is extracted as a change in voltage due to vibration of the diaphragm is an electret. The appearance of materials eliminates the need for a DC high-voltage power supply, and can be easily reduced in size and weight, so that it is widely used from business use to general use.

FIG. 3 illustrates such a condenser microphone using a back electret type capacitor as an example. Referring to FIG. 3, an opening of an upper surface and a bottomed cylindrical contact plate 1 made of a hollow insulating material are provided with an upper surface. A disc-shaped back electrode plate 3 to which an electret material 2 is adhered is attached. A diaphragm 5 is attached to the upper surface of the back electrode plate 3 on the side of the electret material 2 via a ring-shaped spacer 4 having a diameter slightly larger than the outer diameter of the contact plate 1. Diaphragm 5
Is fixed to a support ring 6 having the same shape as the spacer 4. The impedance converter 7 is mounted on a printed circuit board 8 provided outside the contact plate 1. The impedance converter 7 and the contact plate 1 are connected by a conductive spring material 9, and a ground terminal of the impedance converter 7. (Saw
The side 10 is connected to an earth pattern 11 formed on the back surface of the printed circuit board 8.

[0006] The microphone unit 12 having such a general structure is integrally formed with an insulating seat 13 interposed between the contact plate 1 and the printed circuit board 8, and is formed in a cylindrical shape from a metal such as aluminum. The support ring 6 is inserted into the closed housing 16 having the sound collection opening 15 of the housing 14.
A disk-shaped screw member 19 threaded on the outer peripheral surface is screwed into a female screw 18 cut on the inner surface of the open end 17 of the housing 14 in a state in which the ground pattern 11 is in contact with the rear surface of the housing 14. The printed circuit board 8 is held by the housing 14 in a state where the printed circuit board 8 is pressed toward the closed end 16 by contacting the printed circuit board 8 with the housing 14 via the screw member 19 having conductivity.

As a method of attaching to the housing 14 without using a screw, an open end 17 is crimped and bent.
In some cases, the microphone unit 12 is held in the housing 14 by bringing the end of the opening end 17 into contact with the ground pattern 11.

[0006]

In the above-mentioned conventional mounting structure, the ground pattern 11 of the printed circuit board 8 is not provided.
The contact between the housing 14 and the housing 14 is in the longitudinal direction (axial direction) of the housing 14.
The contact pressure is secured by pressing and attaching the microphone unit 12 to the microphone. However, since the contents of the microphone unit 12 are intended to ensure electrical insulation, molded products of synthetic resin are used, and these molded products are used for other parts formed of metal. for softer than, the force in the compression direction is applied to and just deformed from heat and humidity effects both phases俟or <br/> intends.

[0007] When such deformation occurs, the contact pressure between the printed circuit board 8 and the housing 14 becomes unstable, which is a factor that impairs the reliability of the microphone unit. In order to avoid this, conventionally, a method has been adopted in which an elastic body such as rubber is incorporated between the insulating seat 13 and the printed circuit board 8 and the contraction of the contents is absorbed by the elastic body.

However, according to this method, when the elastic force of the elastic body is reduced due to aging, the contraction cannot be absorbed and the reliability cannot be ensured.

The present invention has been made in view of such circumstances of the prior art, and has as its object the purpose of assuring continuity with a ground pattern with a simple structure and ensuring a highly reliable microphone unit housing. An object of the present invention is to provide an attachment structure to a body.

[0010]

In order to achieve the above-mentioned object, the present invention has a sound collecting opening on one end face,
A cylindrical metal housing having an opening on one end face side;
When mounted on a printed circuit board, the gold
A microphone unit housed in the metal housing,
Low on the back side of the printed circuit board (opposite the unit mounting side)
At least the ground pattern is formed on the periphery,
Seal the opening with a printed circuit board and
In a state where the earth pattern is conducted to the metal housing,
The microphone unit in the mounting structure of <br/> Ru microphone unit attached to the metal housing, the pre
The outer diameter of the back side of the printed circuit board is pressed into the opening.
And the outer diameter of the top surface of the board.
Is substantially smaller than the inner diameter of the opening,
And, the ground pattern should be positioned at the end face on the back side.
The printed circuit board is formed in the opening.
The end of the earth pattern is
It comes into contact with the inner surface of the metal housing.
ing. In this case, the outer peripheral edge of the printed circuit board
The surface is also electrically connected to the ground pattern, and the gold
The conductive contact film that contacts the inner surface of the metal housing
Are preferred for obtaining reliable electrical contact.

[0011] According to the invention, the printed circuit board is a trapezoidal cross-sectional
Due to its shape, it is easy to press-fit into the metal housing, and after press-fitting
Is hard to fall out. In addition, the ground pattern
Since it is formed up to the back side end face position,
The ground pattern contacts the inner surface of the housing
I will touch it. Furthermore, from the housing side, the force is applied in a direction perpendicular to the thickness direction of the printed <br/> substrate holding force is generated. Therefore, no force acts on the board in the thickness direction of the board, and the unit contents are held by the housing at a fixed position without contracting.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a preferred embodiment of the present invention. The basic configuration of the microphone is
Since this is the same as the above-described conventional example, the same reference numerals are given to the same components, and the duplicate description will be omitted.

FIG. 1 is a sectional view of a condenser microphone according to a first embodiment of the present invention. In the first embodiment, the end surface 21 of the printed board 8 is formed into a tapered shape in which the closed end 16 of the housing 14 has a small diameter and the open end 17 has a large diameter, and the ground pattern 11 on the outer peripheral portion of the printed board 8 is formed. The portion is set at a position where it can be pressed into and pressed against the inner surface of the housing 14. All other components are configured the same as in the conventional example of FIG.

With this configuration, the microphone unit 12 is attached to the housing 14 in a state where the holding force is applied in the radial direction of the printed circuit board 8 and the ground pattern 11 is in contact with the housing 14. There is no shrinkage problem for the contents of the 12 units.

In order to further secure the contact property and the holding property, the housing 14 may be crimped at the open end 17 and bent so that the edge of the open end 17 contacts the ground pattern 11. Thereby, conduction can be secured at two places. The caulking in this case does not secure the conduction only by caulking as in the conventional case, but merely requires the edge of the opening end 17 to contact the ground pattern 11. Just crimp with the power of.

FIG. 2 is a cross-sectional view of a second embodiment of the present invention.
The outer peripheral surface 21 is subjected to the same plating process as the side surface plating process in the through hole, and the plating layer 22 formed by the plating process is electrically connected to the ground pattern 11. Further, the diameter of the printed circuit board 8 and the thickness of the plating layer 22 are set to dimensions that can be press-fitted and pressed against the inner surface of the housing 14. All other components are configured the same as in the conventional example of FIG.

[0017]

As has been described above devised] According to this invention, when press-fitting the printed circuit board to a metal housing, purine
Since the outer peripheral portion of the grounding pattern formed on bets substrate is formed in contact with the inner surface of the metal housing, the printed circuit board simply pressed into the metal housing, the microphone unit without post-processing, especially easily Ru can be mounted in the housing. In addition, since the contact force and holding force with the metal housing act in a direction orthogonal to the thickness of the printed circuit board, even if the content of the microphone unit shrinks due to temperature change or humidity change, the contact pressure does not change. Not
Therefore, the characteristics of the microphone are stabilized, and the reliability is improved.

The printed circuit board is a ground pattern type.
Large diameter on the surface side (back side), anti-earth pattern formation
The surface side (upper side) has a small diameter trapezoidal cross section, and the outer peripheral end surface of the substrate
Is press-fit into the metal housing because it is tapered.
Easy and hard to remove after press-fitting. In addition, the print base
Conducted to the ground pattern on the outer peripheral surface of the plate,
By forming a conductive contact film that contacts the inner surface,
The more reliable electrical contact between the metal pattern and the metal pattern
can get.

[Brief description of the drawings]

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

FIG. 2 is a longitudinal sectional view of a condenser microphone according to a second embodiment of the present invention.

FIG. 3 is a longitudinal sectional view showing an example of a conventional condenser microphone.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 contact plate 2 electret material 3 back electrode plate 4 spacer 5 diaphragm 7 impedance converter 8 printed board 11 ground pattern 12 microphone unit 13 insulating seat 14 housing 16 closed end 17 open end 21 end surface 22 plating layer

Claims (2)

(57) [Scope of request for utility model registration] 1. A sound pickup opening on one end face side,
A cylindrical metal housing with an opening at the end face, and a printed
When mounted on the board, the metal housing
And a microphone unit housed in the body,
Less on the back side of the printed circuit board (anti-unit mounting side)
A ground pattern is formed on the periphery of both
Seal the opening with a lint board and
In the state where the ground pattern is conducted to the metal housing,
In the microphone unit mounting structure in which the microphone unit is mounted in the metal housing , the printed circuit board has an outer diameter on the back surface side of the substrate that is equal to the opening.
It is large enough to be pressed into
The outside diameter of the opening is substantially smaller than the inside diameter of the opening.
And the ground pattern is the end face on the back side.
Position, and the printed circuit board is open
As it is pressed into the mouth,
An attachment structure for a microphone unit, wherein an end portion is in contact with an inner surface of the metal housing . 2. The method according to claim 1 , further comprising the steps of:
Conducted to the ground pattern, the inner surface of the metal housing
A conductive contact film that is in contact with
A mounting structure for the microphone unit according to claim 1 .