JP2548543Y2 - Microphone - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microphone in which a slit is formed on a front plate of a metal capsule as a sound receiving hole.

[0002]

2. Description of the Related Art FIG. 3 shows a conventional microphone. A front plate 11a is provided on the front surface of the aluminum cylindrical capsule 11.
Are integrally formed, a sound hole 12 is formed in the front plate 11a, and a cloth 13 is attached to the front surface of the front plate 11a. A vibrating membrane ring 14 made of metal is brought into contact with and electrically connected to a peripheral portion of the inner surface of the front plate 11a, and an electret vibrating membrane 15 is attached to a surface of the vibrating membrane ring 14 opposite to the front plate 11a. I have. The electret vibrating film 15 is formed by depositing a metal on one surface of a polymer film, for example, a relatively thick FEP (Fluoro Ethylene Propylene) film having a thickness of 12.5 μm, and the polymer film is polarized. It is attached in contact with the ring 14.

A back electrode 17 is closely opposed to the vibrating membrane 15 via a ring-shaped spacer 16, and the back electrode 17 is held on the front surface of a cylindrical back electrode holder 18. An impedance conversion I is provided in a back chamber 19 formed inside the back pole holder 18.
A C element 21 is provided, and an input terminal 22 of the IC element 21 is provided.
Are connected to the back electrode 17, and the output terminal 23 and the common terminal (not shown) protrude from the back surface of the capsule 11 and are connected to the wiring of the wiring board 24 closing the back surface of the capsule 11. The rear end portion of the capsule 11 is bent on the back surface of the wiring board 24, and each part inside is pressed against the front plate 11a to fix the whole.

[0004]

The sound hole 12 is for receiving sound, and is formed in a circular or slit shape.
Conventionally, the sound hole 12 is in a plane parallel to the front plate 11a. Therefore, there is a problem that the shielding effect is small and the induced noise is large.

[0005]

According to the present invention, the slit for receiving sound is formed in a plane substantially perpendicular to the front plate of the capsule. In particular, according to the invention of claim 2, the slit is located between the outer surface and the inner surface of the front plate.

[0006]

FIG. 1 shows an embodiment of the present invention. Front plate 1 of cylindrical capsule 11 made of metal such as aluminum
1a, a circular recess 31 is formed in the center of the outer surface,
A ring-shaped recess 32 is formed on the inner surface of 1a. The inner diameter of the ring-shaped recess 32 matches the diameter of the circular recess 31 and is the same axis. The bottom surface 32 a of the ring-shaped recess 32 is located on the front surface rather than the bottom surface 31 a of the circular recess 31. A slit 33 is formed at a portion where the peripheral surface coincides with the inner peripheral surface of the ring-shaped concave portion 32. A plurality of tapered connecting portions 3 reaching the bottom surface 31a from the front peripheral edge of the circular concave portion 31
4 are formed integrally at equal angular intervals.

For example, the thickness of the front plate 11a is 0.3 mm, and the inner surface thereof is crushed forward by a ring-shaped mold to form a ring-shaped recess 32, the depth of which is 0.2 mm. The front plate 11a is crushed inward from the front by a circular mold to form a circular concave portion 31 having a depth of 0.2 mm. Therefore, the interval t between the slits 33 is 0.1 mm.
The diameter of the circular recess 31 is 3 mm. Thus, the slit 33 is formed in a plane perpendicular to the front plate 11a and between the outer surface and the inner surface of the front plate 11a.

In the example shown in FIG. 1, an electret polymer film 35 is formed on the inner surface of the front plate 11a,
A narrow distance from the polymer film 35, for example, 25 to 40
A conductive vibration film 36 is provided at a distance of μm. As the conductive vibration film 36, for example, a thin PET having a thickness of 2 to 4 μm is used.
Ni, A on one side of polymer film such as (polyester)
A conductive layer formed by depositing l or the like can be used. In order to provide the narrow space, the inner surface of the front plate 11a is slightly squashed forward while leaving the peripheral portion thereof, and the peripheral portion of the conductive vibration film 36 is in contact with the peripheral portion of the inner surface of the front plate 11a.

The conductive vibration film 36 is attached to and held on a conductive ring 37 on the conductive layer side. One end of a conductive cylindrical body 38 is in contact with the conductive ring 37. A double-sided wiring board 39 is in contact with the other end surface of the conductive cylindrical body 38. The other end surface of the conductive cylindrical body 38 is in contact with a ring pattern 41 formed on the inner surface of the wiring board 39, and the input terminal 22 of the impedance conversion IC element 21 is connected to the pattern 42 connected to the ring pattern 41. Connected, IC element 2
1 and the common terminal not shown in FIG.
Each is connected to each other through hole 43 of the wiring board 39 and is electrically led out. A ring-shaped pattern 44 is formed on the outer surface of the wiring board 39, the polymer film 35 is peeled off from the rear end of the capsule 11, and that portion is bent and pressed against the pattern 44, and the conductive ring 37 and the conductive ring The flexible cylindrical body 38 and the wiring board 39 are held.

To configure the microphone of FIG. 1,
For example, a polymer film is applied to one surface of an aluminum flat plate by heat welding or the like, formed into a cylindrical shape with a bottom by squeezing, a slit 33 is formed in the front plate 11a, and then the polymer film is formed. Polarized into an electret, and thereafter, the conductive ring 37, the conductive cylindrical body 38,
The wiring board 39 on which the IC element 21 is mounted is sequentially encapsulated.
After inserting the capsule 11, the rear end of the capsule 11 may be swaged.

The slit 33 may be formed by forming the circular concave portion 31 and then forming the ring-shaped concave portion 32, or by simultaneously forming the circular concave portion 31 and the ring-shaped concave portion 32. . Further, as shown in FIG. 2A, the slit 33 may be formed by forming a circular concave portion 45 on the inner surface of the front plate 11a and forming a ring-shaped concave portion 46 on the outer surface. In addition, instead of the circular concave portion 31 (45), a rectangular or polygonal concave portion is formed, and instead of the ring-shaped concave portion 32 (46), a rectangular or polygonal concave portion is formed in contact with the outside of the rectangular or polygonal concave portion. The slit may be formed by forming a ring-shaped recess.

As shown in FIG. 2B, the central portion of the inner surface of the front plate 11a is pushed forward and outward, a part thereof is connected in a tapered shape, and the other part is sheared to form a slit 4.
7 may be formed. Conversely, as shown in FIG. 2C, the slit 48 may be formed by extruding the center of the front plate 11a inward. The slit may be formed radially.

Further, in the above description, the present invention is applied to a front electret condenser microphone in which a polymer electret film is formed on the inner surface of the front plate 11a. The present invention can be applied to a back electret condenser microphone on which a molecular electret film is formed and other microphones.

[0014]

As described above, according to the present invention, since the slit for receiving sound is formed in a plane perpendicular to the front plate 11a, the shielding effect is large and the induced noise is reduced. Further, it is difficult for dust and the like to enter, the front cross can be omitted, and the number of parts can be reduced.

Further, as shown in FIG. 1, the sound receiving slit formed between the outer surface and the inner surface of the front plate 11a is as follows.
The front plate 11a has no irregularities as compared with FIGS. 2B and 2C, and the length in the capsule axial direction can be reduced.

[Brief description of the drawings]

FIG. 1A is a sectional view showing an embodiment of the invention of claim 2; FIG.
Is a plan view showing a part of the front plate 11a.

FIG. 2 is a sectional view showing another example of a slit.

FIG. 3 is a sectional view showing a conventional condenser microphone.

Claims (3)

(57) [Scope of request for utility model registration] 1. A microphone in which a slit is formed in a front plate of a metal capsule as a sound receiving sound hole , a first concave portion is formed in a central portion of an outer surface of the front plate, and an inner surface of the front plate is formed by : Outer edge and inner edge of the first recess
Are formed, and the bottom surface of the second recess is located forward of the bottom surface of the first recess.
The slit is formed between these two bottom surfaces, and the outer peripheral edge of the bottom surface of the first concave portion and the bottom surface of the second concave portion
Multiple connections that connect the inner periphery across the slit
A microphone , wherein a part is formed integrally with these bottom surfaces . 2. A sound receiving sound hole on a front plate of a metal capsule.
In the microphone in which the slit is formed , a first concave portion is formed at a central portion of an inner surface of the front plate, and an outer peripheral edge and an inner peripheral edge of the first concave portion are formed on an outer surface of the front plate.
Are formed, and the bottom surface of the second recess is located rearward of the bottom surface of the first recess.
The slit is formed between these two bottom surfaces, and the outer peripheral edge of the bottom surface of the first concave portion and the bottom surface of the second concave portion
Multiple connections that connect the inner periphery across the slit
A microphone , wherein a part is formed integrally with these bottom surfaces . 3. A sound receiving hole in a front plate of a metal capsule.
In a microphone having a slit formed as described above, the center of the front plate is on one side, and the thickness of the front plate is
Extruded to form a protrusion, which is
The front plate is integrally connected to the front plate at a plurality of connection portions.
The slit is formed between the joints.
Microphone.