JP2000165998A - Integral composite electret condenser microphone - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an integral composite electret condenser microphone(ECM). SOLUTION: A couple of ECM units are contained in a common capsule 11 made of a metallic material symmetrically to the left and right, the capsule is sealed by a shield plate 22, a diaphragm circular hole 151 is formed to both left and right sides, a diaphragm ring 15 adhered with a diaphragm 16 is placed to a rear side of the diaphragm circular hole 151, a back electrode holder circular hole 191 is formed to both left and right sides, a back pole holder 19 is provided in the hole 191, to which holder a back pole plate 187 is fixed where an electret dielectric film 20 is formed on its surface, and the diaphragm ring 15 and the back pole holder 19 are contained with a spacer 17 inbetween are contained in the capsule 11 to constitute this integral composite ECM.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an integrated composite electret condenser microphone (hereinafter, the electret condenser microphone is abbreviated as ECM in the following description), and more particularly to a pair of ECMs.
The unitary composite EC in which the units are symmetrically housed in a common capsule made of metal material and sealed with a shielding plate
About M.

[0002]

2. Description of the Related Art A general ECM will be described with reference to FIG. Reference numeral 11 denotes a capsule, and the capsule 11 is formed of a metal cylinder. One end face of the capsule 11 is closed by a front plate 12. However, a sound hole 13 is formed at the center of the front plate 12. A vibrating film 16 attached to a vibrating film ring 15 is accommodated in the capsule 11, and the ring 15 is in contact with the inner surface of the front plate 12. Vibrating film 16 is made of a metal film 16 _1, Erekutoretsuto dielectric film 20 is polarized in its lower surface is adhered. The vibration film 16 is positioned to face the back electrode plate 18 via the spacer 17. The back electrode plate 18 is held by a back electrode holder 19. The back of the holder 19 is closed by a shielding plate 22 via a ring cushion 21, and the rear end of the capsule 11 is bent and swaged against the shielding plate 22. Thus, the diaphragm 16, the back electrode plate 18, the back electrode holder 19, the ring cushion 21, and the shielding plate 22 are mechanically fixed in the capsule 11. Reference numeral 24 denotes an impedance conversion circuit, which includes a field effect transistor, a resistor, and other circuit elements. Metal film 16 ₁ and the back plate 18 constituting the vibrating film 16 is connected to the impedance conversion circuit 24, it is impedance conversion reaches the output end. The vibrating membrane 16 vibrates due to the sound entering through the sound holes 13, and a change in capacitance formed between the vibrating membrane 16 and the back electrode plate 18 is converted into an acoustic signal. The external dimensions of this ECM are extremely small, on the order of less than 4 mm in diameter and 1 mm in thickness. In addition,
The above conventional example is an example of a foil ECM.

[0003] By the way, an extremely small ECM unit originally has a relatively easy variation in acoustic characteristics between products. In configuring a composite ECM,
Since it is not preferable that there is a difference between the acoustic characteristics of the left ECM unit and the acoustic characteristics of the right ECM unit,
Measure the acoustic characteristics of each ECM unit, select and combine two ECM units with similar acoustic characteristics,
It constitutes a composite ECM.

[0004] When a composite ECM is constructed using these extremely small ECM units, these ECM units are fitted and held in parallel to a rubber elastic holder as a left ECM unit and a right ECM unit. It was constituted by doing.

[0005]

As described above, when constructing a composite ECM, the steps of previously measuring the acoustic characteristics of each ECM unit and the step of selecting ECM units having similar acoustic characteristics vary among the ECM units. If these do not exist, they are essentially unnecessary steps, and the addition of this step leads to an increase in the manufacturing cost of the composite ECM.

The configuration in which each separate ECM unit is formed independently and fitted and held in parallel to the holder causes the external dimensions of the composite ECM to increase. In other words, independently configuring these units means that a capsule 11 made of a metal cylinder is required for each unit, and each microphone component housed in the capsule 11 is also formed independently. That is. Composite E with ECM units fitted and held in parallel
Looking at the longitudinal section of the CM, the same capsule 11
Are present, the capsule 11 has a total of four side walls. Regarding the microphone components contained in the capsule 11, the vibration film 16, the spacer 1
7. A back electrode holder 19 for holding the back electrode plate 18 is separately provided. As described above, the external dimensions of each ECM unit
Since they are very small, on the order of less than 4 mm in diameter and 1 mm in thickness, very little overlapping of the components greatly affects the increase in the external dimensions of the assembled composite ECM.

The present invention provides a composite E which has solved the above-mentioned problems.
It provides CM.

[0008]

Means for Solving the Problems Claim 1: One pair of ECM
The unit was housed symmetrically in a common capsule 11 made of a metal material, and sealed with a shielding plate 22 to form an integrated composite ECM. Then, according to claim 2 in integrated composite-ECM as claimed in claim 1, the vibration Makuen'ana 15 ₁ formed in the right and left side portions, the vibrating membrane affixed the vibrating diaphragm 16 on the back surface of the vibration Makuen'ana 15 ₁ comprises a ring 15, provided with a back electrode holder 19 fixing the back plate 18 to electret dielectric layer 20 here forms a back electrode holder circular hole 19 ₁ in the right and left side portions is formed on the surface, the vibration Capsule 11 with membrane ring 15 and back electrode holder 19 interposed with spacer 17
To constitute an integrated composite ECM.

Further, in the integrated composite ECM according to the present invention, the diaphragm holes 15 are formed on both left and right sides.
₁ is formed on the back surface of the vibration Makuen'ana 15 ₁ comprises a vibrating membrane ring 15 affixed the vibrating diaphragm 16 which is metallized electret dielectric film 20, a back electrode holder circular hole 19 ₁ in the right and left side portions A back electrode holder 19 to which a back electrode plate 18 is fixed is provided, and a vibrating membrane ring 15 and a back electrode holder 19 are provided.
Was contained in the capsule 11 with the spacer 17 interposed therebetween to constitute an integrated composite ECM.

In this case, in the integrated composite ECM according to any one of claims 2 and 3, the vibration film 16 attached to the vibration film ring 15 is a single vibration film. Combined ECM consisting of
Was configured. Further, claim 5: claim 2 and claim 4
In the integrated composite ECM described in any of the above,
The two back electrode plates 18 were originally mechanically integrated, and constituted an integrated composite ECM which was cut and worked after polarization by applying a voltage in an integrated state.

Claim 6: In the integrated composite ECM according to any one of claims 2 to 5, the shielding plate 22 has a wiring pattern 31 and terminals 32 formed symmetrically on both surfaces thereof. In addition, an integrated composite ECM was formed in which an impedance conversion circuit 24 in which impedance conversion elements were formed symmetrically on the same silicon substrate was formed.

According to a seventh aspect of the present invention, in the integrated composite ECM according to the sixth aspect, the impedance conversion circuit
Further, an integrated composite ECM in which circuit elements for performing amplification and stereo action are also formed symmetrically to each other was constructed. Claim 8: In the integrated composite ECM according to any one of claims 2 to 7, the vibrating membrane ring 15, the vibrating membrane 16, the spacer 17, the back electrode holder 19, and the shielding plate 22 are provided. An integrated composite E formed in a circular, elliptical, or square shape similar to the outer shape of the capsule 11
The CM was configured.

[0013] Claim 9: Claims 1 to 8
In the integrated composite ECM described in any of the above,
An integrated composite ECM was formed in which the central axis directions of the left ECM unit L and the right ECM unit R were crossed to give an angle.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, an embodiment of the present invention will be described.
This will be described with reference to FIG. Reference numeral 11 denotes a capsule, which is formed of a metal cylinder having a very low height. The outer shape of the metal cylinder is circular, elliptical, or square, and one end face is closed by a front plate 12. The outer shape of the metal cylinder of the embodiment of FIG. 1 is elliptical or oval. In addition, sound holes 13 are formed in the front plate 12 so as to correspond to the left ECM unit L and the right ECM unit R configured on the left and right. Hereinafter, each member accommodated in the capsule 11 will be sequentially described with reference to FIGS.

Referring to FIG. 2, reference numeral 15 denotes a vibrating membrane ring. The vibrating membrane ring 15 is made of a thin metal
Formed in a circle, ellipse, or square similar to the outer shape of
The left and right sides of the diaphragm 15 correspond to the left ECM unit L and the right ECM unit R formed on the left and right, respectively.
Forming _one . Reference numeral 16 denotes a vibrating membrane. Vibrating membrane 16
Has an outer shape of a circle, an ellipse, or a square similar to the diaphragm 15 and the same dimensions. The vibrating film 16 is attached to the lower surface of the vibrating film ring 15, and one common vibrating film 16 is connected to the left and right ECs.
This means that M vibrating membranes are formed. This vibrating membrane 16
It is given the room to vibrate by the vibration Makuen'ana 15 ₁ of the diaphragm ring 15. Vibrating membrane 16 may be a vibrating membrane with a deposit of metal film 16 ₁ on the synthetic resin film.

Referring to FIG. 3, reference numeral 17 denotes a spacer made of a thin insulating material plate. Spacer 17 is also circular shape similar to the outer periphery thereof with a capsule 11, elliptical, or formed in a rectangular shape, corresponding to the vibration Makuen'ana 15 ₁ on the left and right sides two spacers circular hole 17 ₁ is formed ing. Referring to FIG. 4, reference numeral 18 denotes a back electrode plate. The two back plates 18 face the vibrating membrane 16 and independently form electrodes forming capacitors. An electret dielectric film 20 is formed on the surface of the back electrode plate 18. These two back electrode plates 18 are originally mechanically integrated, and are polarized by applying a voltage in an integrated state. When the polarization is completed, it is cut off, so that the variation of the polarization voltage between the back plates 18 can be completely eliminated.

Reference numeral 19 denotes a back pole holder. The back pole holder 19 is also formed in a circular, elliptical, or quadrangular shape similar in shape to the capsule 11 and has back pole holder circular holes 19 ₁ formed on both left and right sides thereof in correspondence with the spacer circular holes 17 _1. ing. The upper peripheral portion of the back electrode holder circular hole 19 ₁ is formed an annular step portion 19 _2, here is fitted and fixed the back plate 18. The conversion circuit housing 1 is provided on the lower surface of the center
9 ₃ is formed.

Referring to FIG. 5, reference numeral 22 denotes a shielding plate for sealing the lower end opening of the capsule 11. The outer shape of the shielding plate 22 is also circular, elliptical, or quadrangular, similar to the capsule 11. Wiring pattern 3 on both sides of shielding plate 22
1 is formed, and a terminal 32 protruding from the outer surface is formed. The wiring pattern 3 and the terminal 32 are formed symmetrically to each other.

Reference numeral 24 denotes a left ECM unit L and a right ECM
This is an impedance conversion circuit in which the impedance conversion elements of each unit R are formed symmetrically on the same silicon substrate. Further, in the impedance conversion circuit 24, circuit elements for performing amplification and stereo action are formed symmetrically with each other. Here, the vibration film 16 attached to the lower surface of the vibration film ring 15 is attached to the vibration film ring 15.
In the capsule 11 with the front plate 12 side of the capsule 11. Next, the spacer 17 is accommodated. here,
The back plate 18 that electret dielectric film 20 is formed on the surface and accommodates the back electrode holder 19 which is fitted and fixed to the annular step 19 ₂ back plate 18 to the spacer 17 side. When the opening of the capsule 11 is shielded by the shield plate 22, the capsule 11 is sealed by caulking the opening end of the capsule 11 to the shield plate 22, and the assembly of the composite ECM is completed. The vibrating membrane 16 forming one electrode of the electret capacitor and the back electrode plate 18 forming the other electrode are electrically connected to the terminal 32 via the capsule 11, the wiring pattern 31, and the impedance conversion circuit 24. However, the detailed description is omitted.

Although the above embodiment is an example of the back ECM in which the electret dielectric film 20 is formed on the surface of the back electrode plate 18, the present invention does not require the electret dielectric film 20 to be formed on the surface of the back electrode plate 18. Te, can be a metal film 16 ₁ is formed by such film deposition techniques deposited electret dielectric film 20, it is applied to the wheel ECM had affixed to the vibrating membrane ring 15. Referring to FIG. 6, the diaphragm ring 15 is formed by forming a thin metal plate into a circular shape, an elliptical shape, or a rectangular shape similar to the outer shape of the capsule 11, and has left and right left ECM units L and Right ECM
Forming a vibration Makuen'ana 15 ₁ corresponding to the unit R. The vibrating membrane 16 has a circular, elliptical, or quadrangular shape similar in shape to the vibrating membrane ring 15 and has the same dimensions. The vibrating membrane 16 is attached to the lower surface of the vibrating membrane ring 15, and a common one vibrating membrane 1 is provided.
6 constitutes the left and right ECM vibrating membranes.
Metal film 16 ₁ is formed on the upper surface of the electret dielectric film 20.

Referring to FIG. 7, there is shown a composite ECM in which the left ECM unit L and the right ECM unit R constituting the composite ECM are slightly angled by intersecting the central axis directions. When a composite ECM is used as a stereo ECM, it is desirable to collect sound with a wide spread to the left and right. You will be collecting sound. Here, the left ECM unit L and the right ECM unit R intersect in the direction of the central axis to give a slight angle, thereby making it possible to obtain a stereo ECM that collects a sound having a large spread to the left and right.

[0022]

As described above, according to the present invention, two ECM units are integrated to form an integrated composite ECM. This reduces variations in the characteristics of the ECM units and reduces the product quality. While reducing the external dimensions,
Manufacturing costs can also be reduced. And left ECM
By assembling with a certain angle between the central axis of the unit and the central axis of the right ECM unit, it is possible to configure an integrated composite ECM that collects a sound that has a large spread to the left and right.

In particular, by forming the members constituting the composite ECM symmetrically, variations in the characteristics of the ECM unit can be reduced. That is, the vibrating membrane ring, the vibrating membrane, the spacer, the back electrode holder, and the shielding plate are formed in a circular, elliptical, or square shape similar to the outer shape of the capsule. The two back electrode plates are originally mechanically integrated, and by applying a voltage in an integrated state and performing cutting after polarization, no polarization bias occurs between the two back electrode plates. In addition, the variation of the characteristics of the ECM unit is reduced by forming the wiring pattern and the terminal symmetrically with respect to the shielding plate and forming the impedance conversion element symmetrically with each other on the same silicon substrate. .

[Brief description of the drawings]

FIG. 1 illustrates an embodiment.

FIG. 2 is a diagram illustrating a vibrating membrane and a vibrating membrane ring.

FIG. 3 illustrates a spacer.

FIG. 4 is a diagram illustrating a back electrode plate and a back electrode holder.

FIG. 5 illustrates a shielding plate.

FIG. 6 is a diagram for explaining another embodiment.

FIG. 7 is a diagram illustrating a stereo ECM.

FIG. 8 is a diagram illustrating a conventional example.

[Explanation of symbols]

REFERENCE SIGNS LIST 11 capsule 12 front plate 13 sound hole 15 diaphragm ring 15 ₁ diaphragm ring hole 16 diaphragm 16 ₁ metal film 17 spacer 17 ₁ spacer circular hole 18 back electrode plate 18 ₁ through hole 19 back electrode holder 19 _{1 back} electrode holder Circular hole 19 ₂ Ring step 19 ₃ Conversion circuit housing 20 Electret dielectric film 21 Ring cushion 22 Shielding plate 24 Impedance conversion circuit 31 Wiring pattern 32 Terminal LECM unit R Right ECM unit

Claims (9)

[Claims] 1. An integrated composite ECM wherein a pair of ECM units are symmetrically accommodated in a common capsule made of a metal material and sealed with a shielding plate. 2. The integrated composite ECM according to claim 1.
At the left and right sides, vibrating membrane holes are formed, and a vibrating membrane ring with a vibrating membrane attached to the back of the vibrating membrane hole is provided. An integrated composite E comprising a back electrode holder to which a back electrode plate on which an electret dielectric film is formed is fixed, and the vibrating membrane ring and the back electrode holder are housed in a capsule with a spacer interposed therebetween.
CM. 3. An integrated composite ECM according to claim 1.
In each of the left and right sides, a vibrating membrane hole is formed, and on the back surface of the vibrating membrane hole, a vibrating membrane ring in which a metal-deposited vibrating membrane is attached to an electret dielectric film is provided. A back electrode holder having a hole formed therein and a back electrode plate fixed thereto is provided, and the vibrating membrane ring and the back electrode holder are housed in the capsule 11 with a spacer interposed therebetween.
CM. 4. The integrated composite ECM according to claim 2, wherein the vibration film attached to the vibration film ring is formed of one common vibration film. Characteristic integrated composite E
CM. 5. The integrated composite ECM according to claim 2, wherein the two back plates are originally mechanically integrated, and the two back plates are mechanically integrated. An integrated composite ECM, which is obtained by applying a voltage, polarizing, and then cutting. 6. The integrated composite ECM according to claim 2, wherein the shielding plate has wiring patterns and terminals formed symmetrically on both surfaces thereof, and an impedance conversion element. Wherein an impedance conversion circuit is formed symmetrically on the same silicon substrate. 7. An integrated composite ECM according to claim 6.
The integrated composite ECM according to any one of claims 1 to 3, wherein the impedance conversion circuit further includes circuit elements for performing amplification and stereo action symmetrically to each other. 8. The integrated composite ECM according to claim 2, wherein the diaphragm ring, the diaphragm, the spacer, the back electrode holder, and the shielding plate have a shape similar to the outer shape of the capsule. An integrated composite ECM characterized by being formed into a circle, an ellipse, or a square. 9. An integrated composite ECM according to any one of claims 1 to 8, wherein the left ECM unit L and the right ECM unit R intersect with each other in the central axis direction to form an angle. A unique integrated ECM.