JPH0523698U - Electret condenser microphone unit - Google Patents

Abstract

(57) [Summary] [Purpose] To facilitate automatic assembly. An electret film 26 is formed on the inner surface of the front plate of the aluminum cylindrical capsule 11, and a conductive vibrating film 29 is arranged in close proximity to the electret film 26. The vibrating film 29 is held by a conductive holding body 32. Holder 32 and double-sided wiring board 2
A conductive tubular body 34 'is interposed between the 4'and the ring-shaped conductor pattern 51, if necessary. The impedance conversion IC element 21 is mounted on the double-sided wiring board 24 '. I
The input terminal 22 of the C element is soldered to the pattern 52 extended from the pattern 51.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a condenser microphone unit using an electret.

[0002]

[Prior Art]

 FIG. 4A shows a conventional foil electret condenser microphone unit. A front plate 11a is integrally formed on the front surface of the aluminum cylindrical capsule 11, 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 contacted and electrically connected to the inner peripheral edge of the front plate 11a, and an electret vibrating membrane 15 is attached to the surface of the vibrating membrane ring 14 opposite to the front plate 11a. There is. A metal is vapor-deposited on one side of the electret vibrating film 15 and 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, and the vapor-deposited film vibrates. It is attached in contact with the membrane ring 14.

A back pole 17 is closely opposed to the vibrating film 15 via a ring-shaped spacer 16, and the back pole 17 is held on the front surface of a tubular back pole holder 18. An impedance conversion IC element 21 is arranged in a back chamber 19 formed inside the back electrode holder 18, an input terminal 22 of the IC element 21 is connected to the back electrode 17, and an output terminal 23 and a common terminal ( (Not shown) is projected from the back surface of the capsule 11 and is connected to the wiring of the wiring board 24 that closes 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 the respective internal parts are pressed against the front plate 11a to be fixed as a whole.

FIG. 4B shows a conventional back electret condenser microphone unit. In the foil electret type of FIG. 4A, the vibrating film itself is electretized, whereas in the back electret type, the electret high molecular weight film 26 is adhered to the upper surface of the back electrode 17. That is, a polymer film such as an FEP film is welded or adhered to the upper surface of the back electrode 17 as an electret material, and polarized to be electretized.

5 to 10 show a front electret type (an electret polymer film 26 is disposed in close proximity to the front surface of the conductive vibration film 29, which is proposed in a stage before obtaining the present invention, It means that there is no back pole) and will be explained in order below. In these figures, parts corresponding to those in FIG. 4 are designated by the same reference numerals. An electret polymer film 26 is applied to the inner surface of the front plate 11a of the microphone capsule 11 shown in FIG. For example, as shown in FIG. 7A, a polymer film, for example, FEP film 28 is continuously heat-welded on one surface of an aluminum plate 27 having a thickness of 0.3 to 0.35 mm to a thickness of about 12.5 to 25 μm. As the aluminum plate 27, JIS: A1100P 340 ° C. to 410 ° C. air-cooled or furnace-cooled annealed product is soft and has good formability in the subsequent press working. Further, it is preferable that the aluminum plate is subjected to a chemical conversion treatment to form an oxide film on the surface thereof so that the adhesive strength of the polymer film 26 becomes stronger. Similarly, the surface of the aluminum plate 27 on which the polymer film is to be welded can be subjected to corona discharge treatment to increase the adhesive force of the polymer film 26. The polymer film 26 can be continuously welded to the aluminum plate 27 with a thermocompression bonding roll.

The aluminum plate 27 coated with the polymer film 26 is pressed with a drawing die to form the FEP film 28 inside as shown in FIG. The polymer film 26 at the edge is peeled off by about 0.8 mm to expose the aluminum background, and the sound hole 12 common to the front plate of the capsule 11 and the FEP film 28 is formed. Next, electron beam polarization is applied to the portion of the FEP film 28 that is adhered to the inner surface of the front plate 11a of the capsule 11 to obtain an electret polymer film 26 as shown in FIG. 7C.

Returning to the description of FIG. 5, the conductive vibrating membranes 29 are arranged facing each other with a narrow interval, for example, 25 to 40 μm, except for the peripheral portion of the electret polymer film 26. As the conductive vibration film 29, for example, an extremely thin PET (Polyester ter) film or polyphenylene sulfide (PPS) film having a thickness of 2 to 4 μm is formed by vapor-depositing Ni, Al or the like on one surface to form a conductive layer. Can be used. The front plate 11a is slightly extruded forward leaving the peripheral edge portion thereof to form a shallow concave portion 31, and the peripheral edge portion of the electrically conductive vibrating film 29 is brought into contact with the peripheral edge portion of the electret polymer film 26 to form the concave portion 31. A gap is formed between the electret polymer film 26 and the conductive vibrating membrane 29 corresponding to the depth of the. Although this concave portion 31 is not shown in FIGS. 7B and 7C, it is made in advance when the capsule is made by pressing.

A conductive holding body 32 is housed in the capsule 11, holds the conductive vibrating membrane 29 on the front surface of the conductive holding body 32, and is electrically connected to each other, that is, the conductive vibrating membrane 29 has the above-mentioned structure. The conductive layer is in contact with the conductive holder 32, and the conductive holder 32 constitutes the back chamber 19 on the back surface of the conductive vibration film 29. The conductive holding body 32 is made of, for example, a metal forged product, and includes a cylindrical body portion 32a that fits into the capsule 11 and a partition wall portion 32b that divides the inside into a front portion and a rear portion. An epoxy-based conductive adhesive is applied to the front surface of the conductive holding body 32, and the conductive vibration film 29 having a tension applied thereto is adhered to the conductive layer side. The back chamber 19 is between the partition wall portion 32b and the conductive vibration film 29. Since the polymer film 28 is attached to the inner peripheral surface of the capsule 11, the conductive holder 32 is electrically insulated from the capsule 11.

The back surface of the capsule 11 is closed by the wiring board 24. In this example, the wiring board 24 is opposed to the back surface of the conductive holder 32, the rear end of the capsule 11 is bent on the back surface of the wiring board 24, and the holder 32 and the wiring board 24 are pressed against the front plate 11a. Fixed. The impedance conversion IC element 21 is arranged between the wiring board 24 and the partition wall portion 32b, the input terminal 22 of the IC element 21 is connected to the partition wall portion 32b, and the output terminal 23 and the common terminal (not shown) are wired. It is led out to the outside of the substrate 24 and connected to its output wiring and common wiring, respectively. Further, the bent inner edge of the capsule 11 is connected to the common wiring on the peripheral edge of the back surface of the wiring board 24.

According to this configuration, the vibrating membrane 29 vibrates in response to the acoustic signal coming from the front surface, and the electrostatic capacitance between the conductive vibrating membrane 29 and the front plate 11a changes, thereby acting as a condenser microphone. To do. As the conductive vibration film 29, a polymer film having conductive layers formed on both sides may be used. In this case, both conductive layers are electrically connected. The conductive holding body 32 is not limited to the case where the whole is made of a metal material, but may have a shape required for an insulating material, and the surface of the insulating material may be plated with metal to be used as the conductive holding body. In order to form the space between the electret polymer film 26 and the vibrating film 29, the projections may be provided at appropriate intervals from the front plate 11a to the holder 32 side, and the recess 31 may be omitted. A cloth may be attached to the front surface of the front plate 11a.

Microphone of FIG . 6 As shown in FIG. 6A with the same reference numerals as those corresponding to FIG. 5, the conductive holder 32 has a short axis, for example, the conventional vibrating membrane shown in FIG. The same ring 14 may be used, and a cylindrical body 34 made of an insulating material such as ABS resin may be interposed between the conductive holder 32 and the wiring board 24. In this case, a recess 35 is formed in the front surface of the cylindrical body 34, the end portion of the input terminal 22 of the IC element 21 is bent, and the end portion of the input terminal 22 is placed inside the recess 35. By pressing the tubular body 34 against the conductive holding body 32 while being positioned slightly forward of the front surface of the tubular body 34, the input terminal 22 elastically comes into contact with the conductive holding body 32 and the electrical holding is performed. It is connected to the.

Further, in the structure shown in FIG. 6A, when the concave portion 31 is formed, the outer surface of the front plate 11a of the capsule 11 is made flat without forming steps and has a good appearance, and the outer surface of the front surface plate 11a is made of aluminum. It is in a condition that it is easy to print or put a cloth to make the shines less noticeable. Further, similarly to FIG. 5, when the capsule 11 is pressed, the polymer film 28 at the rear end portion of the capsule 11 is removed at the same time, and the aluminum background is exposed to remove the rear end portion of the capsule 11. By caulking the back surface of the wiring board 24, the capsule 11 is automatically connected to the common wiring on the peripheral edge of the back surface of the wiring board 24. Although the back surface side of the cylindrical body 34 is shown as being integrally closed, the back surface may be an open surface. By inserting the holder 32 holding the vibrating membrane 29 into the capsule 11, and then inserting the IC element 21, the wiring board 24, and the tubular body 34 integrally assembled in advance into the capsule 11. It can be easily assembled.

By selecting the diameter and the number of the sound holes 12 of the front plate 11 a of the capsule 11, it is possible to prevent a peak from being generated by the resonance frequency f ₀ of the vibrating membrane 29 in the high frequency range of the frequency characteristics of the microphone. it can. For example, when the outer diameter of the capsule 11 is 9.3 mm and the effective diameter of the vibrating membrane 29 is 7.0 mm, the diameter is 1.0 mm on a circle with the diameter of 3.5 mm centered on the axis of the capsule 11. When 5 sound holes 12 are formed at equal angular intervals, or when 6 0.8 mm sound holes 12 are formed at equal angular intervals, the high frequency range in the sensitivity frequency characteristic is as shown by the curve 36 in FIG. 6B. A peak occurs at. However, when the number of 0.8 mm sound holes 12 is 5, the peak in the high frequency band disappears as shown by the curve 37 and the sound becomes flat. It should be noted that if the diameter of the sound holes 12 is further reduced to 5 for 0.6 mm or 4 for 0.8 mm, the high range is lowered too much as shown by the curve 38. Therefore, it is best to provide five pieces with a diameter of 0.8 mm.

Microphone of FIG. 8 As shown in FIG. 8, the inside of the holding body 32 is kept with a slight distance (for example, 20 to 30 μm) from the vibration membrane 29 except for the portion holding the vibration membrane 29 as the holding body 32. It is also possible to close the body as a whole and form a sound hole 39 in the closed portion 32a so that the peak in FIG. 6B in the high frequency range can be suppressed by the diameter and number of the sound holes 39. In this case, five large sounds 12, for example 1.0 mm, are formed so as not to affect the frequency characteristic.

In FIGS. 6A and 8, the electret polymer film 26 may be attached only to the front plate 11 a with an adhesive, and the polymer film 28 on the inner peripheral surface of the capsule 11 may be omitted. As shown in FIG . 9A, the FEP film 42 is attached to one surface of the circular aluminum plate 41 by welding or adhesion, the sound hole 12 is opened, and then the FEP film 42 is separated and the electret. The polymer film 26 may be used, and as shown in FIG. 9B, the aluminum plate 41 may be press-fitted into the front opening of the cylindrical body 43 of aluminum to be integrated into the capsule 11.

Similarly, as shown in FIG. 10, the electret polymer film 26 formed on one surface of the aluminum plate 41 is fixed to the front flange 43a of the tubular body 43 by press fitting from the inner surface. The capsule 11 may be used. In the above description, a spacer may be interposed between the peripheral portion of the vibrating film 29 and the electret polymer film 26 to correct the variation in the polarization strength of the electret polymer film 26 due to the product. In this case, the recess 31 may be omitted.

In the foil electret type of FIG. 4, since the electret vibrating film 15 is used, it is difficult to reduce the thickness to 12.5 μm or less, and it is not possible to increase the sensitivity as much, and at −45 dB at 1 KHz. However, in the above-mentioned front electret type, since the vibrating membrane 29 does not need to be electret, the thickness can be reduced to, for example, 2 μm, and the structure of FIG. 6A can improve −38 dB and 7 dB at 1 KHz. As a result, the S / N is 45 dB or more, which is 5 dB better than the conventional product. Similar performance can be expected for other front electret types.

Further, since the electret polymer film 26 is formed on the inner surface of the capsule, its thickness can be increased, for example, 25 μm, and the variation in polarization strength due to the product is small and the stability is good. can do.

[0019]

[Problems to be solved by the device]

 In the conventional foil electret type and back electret type described above, and in the front electret type proposed at the stage before obtaining the present invention, it is difficult to automatically incorporate and wire the IC element 21. The structure was a bottleneck in automating the manufacture of the microphone unit. Since automatic assembly was not possible, productivity could not be improved, and cost could not be reduced. The present invention has been made in view of such a situation as described above, and an object thereof is to provide a structure capable of automatically assembling a microphone unit, including a built-in wiring of an IC element.

[0020]

[Means for Solving the Problems]

 (1) In the electret condenser microphone unit according to claim 1, a metal cylindrical capsule having a sound hole formed in a front plate and a hole which is attached to the inner surface of the front plate of the capsule and communicates with the sound hole. Electret polymer film having, a conductive vibrating film disposed in close proximity to the polymer film, a conductive holding body that holds the peripheral edge of the conductive vibrating film, and a wiring that closes the back surface of the capsule. A board and an impedance conversion IC element mounted on the upper surface of the wiring board in the capsule are provided.

The wiring board is a double-sided wiring board, and has a peripheral conductor pattern on the upper surface thereof, which is in contact with the rear end surface of the holder, and a conductor pattern extending from the peripheral conductor pattern. And a conductor pattern connected to the input terminal. (2) A conductive tubular body may be interposed between the holding body and the wiring board (corresponding to claim 2).

(3) In the electret condenser microphone unit according to claim 3, a metal cylindrical capsule having a sound hole formed in a front plate and an inner surface of the front plate of the capsule are covered with the sound hole. An electret polymer film having communicating holes, a conductive vibrating film arranged in close proximity to the polymer film, and a ring-shaped spacer that defines a distance between the conductive vibrating film and the polymer film, A conductive tubular body that sandwiches the peripheral portion of the conductive vibration film together with the spacer, a wiring board that closes the back surface of the capsule, and an impedance conversion device mounted on the upper surface of the wiring board in the capsule. And an IC element.

The wiring board is a double-sided wiring board, and has a peripheral conductor pattern on the upper surface thereof, which is in contact with the rear end face of the tubular body, and a conductor pattern extending from the peripheral conductor pattern, and the input of the IC element is input. And a conductor pattern connected to the terminal. (4) In the electret condenser microphone unit according to claim 4, a metal cylindrical capsule having a sound hole formed in a front plate, an electret vibrating film arranged to face the front plate of the capsule, and an electret vibration thereof. A back electrode disposed in close proximity to the back surface of the film, a conductive tubular body that holds the back electrode at the front end, a wiring board that closes the back surface of the capsule, and the wiring board in the capsule. And an IC element for impedance conversion mounted on the upper surface of the.

The wiring board is a double-sided wiring board, and has a peripheral conductor pattern on the upper surface thereof, which is in contact with the rear end surface of the holder, and a conductor pattern extending from the peripheral conductor pattern, and the input terminal of the IC element. And a conductor pattern connected to. (5) In the electret condenser microphone unit according to claim 5, a metal cylindrical capsule having a sound hole formed in a front plate, a conductive vibrating film arranged to face the front plate of the capsule, and a conductive film thereof. A back pole disposed in close proximity to the back of the vibrating membrane, an electret high molecular film formed on the front of the back pole facing the conductive vibrating membrane, and holding the back pole at the front end. A conductive tubular body, a wiring board that covers the back surface of the capsule, and an impedance conversion IC element mounted on the upper surface of the wiring board in the capsule.

The wiring board is a double-sided wiring board, and has a peripheral conductor pattern on the upper surface thereof, which is in contact with the rear end surface of the holder, and a conductor pattern extending from the peripheral conductor pattern, and the input terminal of the IC element. And a conductor pattern connected to.

[0026]

【Example】

1 to 3, parts corresponding to those in FIGS. 4 to 10 are designated by the same reference numerals, and a duplicate description will be omitted. Example of FIG. 1A (corresponding to claim 1) In the example described in the section of the prior art, the impedance conversion IC element 21 has the input terminal 22, the output terminal 23, and the common terminal formed of lead wires. The wiring board 24 is a single-sided printed board, and the conductor pattern is formed only on the back surface thereof. On the other hand, in this invention, the double-sided wiring board 24 'is used as the wiring board. The IC element 21 is preferably a thin chip type. In order to electrically connect the conductive vibration film 29 and the input terminal 22 of the IC element 21, a ring-shaped conductor pattern 51 is formed on the peripheral edge of the upper surface of the double-sided wiring board 24 ', and a conductive holder is formed thereon. The rear end surface of 32 is superposed coaxially. The conductor pattern 52 to which the input terminal 22 is soldered is extended from the ring-shaped conductor pattern 51. The conductor patterns 53 and 54 to which the output terminal 23 and the common terminal 23 'of the IC element 21 are to be soldered are connected to the conductor patterns 55 and 56 on the back surface through through holes, respectively. A ring-shaped conductor pattern 57 is formed on the peripheral edge of the back surface of the wiring board 24 as in the previous embodiments, and a common wiring pattern 58 is extended from the ring-shaped conductor pattern 57. Although not shown, the conductor pattern 56 connected to the common terminal 23 'of the IC element is connected to the common wiring pattern 58.

In a mass production line, the IC element 21 is automatically placed at a predetermined position on the double-sided wiring board 24 'by a mounter device and automatically soldered by solder reflow. At that time, the through hole is filled with solder, and air escape of the back chamber 19 through the through hole is prevented. In this example, the front plate 11a has slit holes 12 '(for example, width 0.4 mm, length 2.0 mm) formed in the central portion, instead of the plurality of circular sound holes 12 that have been used so far. To assemble the microphone unit shown in FIG. 1A, first, the capsule 11 is polarized, then the conductive holding body 32 holding the conductive vibration film 29 is inserted, and then the double-sided wiring board 24 ′ on which the IC element 21 is mounted is mounted. Insert and finally crimp the back end of the capsule 11. These assembly operations can be easily automated.

Embodiment of FIG . 1B (corresponding to claim 2) As shown in FIG. 1B, a conductive cylindrical body 34 'may be interposed between the conductive holder 32 and the double-sided wiring board 24'. it can. 2 embodiment (corresponding to claim 3) In the embodiment of FIG. 2A, the recess 31 is not provided on the front inner surface of the capsule 11, and the ring-shaped spacer 16 is the electret polymer on the back surface of the front plate of the capsule 11. It is interposed between the film 26 and the conductive vibration film 29. Further, a conductive tubular body 34 'is arranged between the conductive vibration film 29 and the double-sided wiring board 24'. The conductive vibration film 29 is held by either the rear end surface of the spacer 16 or the front end surface of the conductive cylindrical body 34 '. The spacer 16 defines the gap between the electret polymer film 26 and the conductive vibration film 29 to a predetermined size.

As a modified example of FIG. 2A, as shown in FIGS. 2B and 2C, the front surface of the capsule 11 is pierced inward in a rectangular shape, that is, it is pushed inward with a slight step, and one of the two opposing A sound hole composed of a narrow slit 61 is formed at the edge to form the front plate 11a. In the conductive vibrating film 29 of this example, a conductive layer is formed on the surface facing the conductive cylindrical body 34 '. Needless to say, a gap is formed between the conductive vibration film 29 and the electret polymer film 26.

In FIGS. 2A and 2B, since a narrow slit is used as the sound hole, it is difficult for dust and lead wires to enter the sound hole, and there is no danger of damaging the vibrating membrane 29. It can be omitted. Embodiment of FIG. 3A (corresponding to claim 4) The embodiment of FIGS. 1 and 2 is a front electret type, while FIG. 3A is a case of applying the invention to the wheel electret type of FIG. 4A. Is. The back electrode 17 is held by the electrically conductive tubular body 34 '. An insulating ring 60 is fitted on the outer surfaces of the back electrode 17 and the conductive tubular body 34 ′ so that they do not come into contact with the capsule 11.

Embodiment of FIG . 3B (corresponding to claim 5) FIG. 3B shows a case where the present invention is applied to the back electret type of FIG. 4B. The conductive vibration film 29 and the electret polymer film 26 are used. Others are the same as that of FIG. 3A.

[0032]

[Effect of the device]

 As described above, according to the present invention, the double-sided wiring board 24 'is adopted, and on the upper surface thereof, the peripheral conductor pattern 51 and the conductive holding body 32 or the conductive cylindrical body 34' which are in contact with each other are provided. A conductor pattern 52, which extends from the conductor pattern 51 and is connected to the input terminal 22 of the IC element 21, is formed, and the IC element 21 is automatically pre-assembled and wired on the upper surface of the double-sided wiring board 24 ', and the wiring board is encapsulated. Automatically assembling the microphone unit can be easily performed by sequentially inserting the other components into the casing 11, and finally caulking the rear edge of the capsule. As a result, productivity can be greatly improved and cost can be reduced.

In this invention, since the double-sided wiring board is used, the terminals can be led out as needed, and the usage can be expanded. In addition, chip resistors can be easily mounted on the top or bottom of the board, and the low-frequency cutoff in the frequency characteristics of the microphone can be cut, expanding the range of applications.

[Brief description of drawings]

1A and 1B are cross-sectional views of an embodiment of a front electret type microphone corresponding to claims 1 and 2, respectively.

2A and 2B are cross-sectional views of an embodiment of a front electret type microphone corresponding to claim 3, and C is a perspective view of B.

3A is a cross-sectional view of an embodiment of a wheel electret microphone corresponding to claim 4, and B is a cross-sectional view of an embodiment of a back electret microphone corresponding to claim 5. FIG.

FIG. 4A is a sectional view of a conventional wheel electret microphone, and B is a sectional view of a conventional back electret microphone.

FIG. 5 is a cross-sectional view of a front electret-type microphone proposed at a stage before obtaining the present invention.

FIG. 6A is a cross-sectional view of another front electret type microphone proposed before the invention is obtained, and B is a diagram showing its sensitivity frequency characteristic.

FIG. 7 is a process cross-sectional view for explaining the manufacture of the capsule 11 of FIGS. 5, 6, and 8.

FIG. 8 is a sectional view of yet another front electret-type microphone proposed in a stage before obtaining the present invention.

9A is a perspective view showing another example of capsule manufacturing, and FIG. 9B is a cross-sectional view of a front electret type microphone (proposed at a stage before obtaining the present invention) using the capsule.

FIG. 10 is a sectional view of yet another front electret-type microphone proposed in a stage before obtaining the present invention.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshiro Ito 3024-38 Nakayama, Kurate-cho, Kurate-gun, Fukuoka Prefecture Hosiden Kyushu Co., Ltd. Inside Sidden Kyushu Co., Ltd. (72) Inventor Kiyoyuki Ota 3024-38 Nakayama, Kurate-machi, Kurate-gun, Fukuoka Hosiden Kyushu Co., Ltd.

Claims (5)

[Scope of utility model registration request] 1. A metal cylindrical capsule having a sound hole formed in a front plate, and an electret polymer film having a hole which is attached to the inner surface of the front plate of the capsule and has a hole communicating with the sound hole. A conductive vibrating film disposed in close proximity to the polymer film, a conductive holding body that holds the peripheral edge of the conductive vibrating film, a wiring substrate that closes the back surface of the capsule, and in the capsule, An impedance conversion IC element mounted on the upper surface of the wiring board, wherein the wiring board is a double-sided wiring board,
A peripheral conductor pattern that is in contact with the rear end surface of the holding body,
An electret condenser microphone unit, comprising a conductor pattern extending from a conductor pattern on the periphery of the conductor pattern and connected to an input terminal of the IC element. 2. The electret condenser microphone unit according to claim 1, wherein a conductive cylindrical body is interposed between the holding body and the wiring board. 3. A cylindrical metal capsule having a sound hole formed in a front plate, and an electret polymer film having a hole which is attached to the inner surface of the front plate of the capsule and has a hole communicating with the sound hole. A conductive vibrating film disposed in close proximity to the polymer film, a ring-shaped spacer that defines a distance between the conductive vibrating film and the polymer film, and a peripheral portion of the conductive vibrating film together with the spacer. And a wiring board for closing the back surface of the capsule, and an impedance conversion IC element mounted on the upper surface of the wiring board in the capsule, wherein the wiring board has double-sided wiring. A substrate, on the top of which,
A peripheral conductor pattern that contacts the rear end surface of the tubular body,
An electret condenser microphone unit, comprising a conductor pattern extending from a conductor pattern on the periphery of the conductor pattern and connected to an input terminal of the IC element. 4. A metal cylindrical capsule having a sound hole formed in a front plate, an electret vibrating film arranged to face the front plate of the capsule, and a back face of the electret vibrating film in close proximity to each other. An arranged back pole, a conductive tubular body that holds the back pole at the front end, a wiring board that closes the back surface of the capsule, and an impedance converter mounted on the top surface of the wiring board in the capsule. And an IC element, wherein the wiring board is a double-sided wiring board,
A peripheral conductor pattern that is in contact with the rear end surface of the holding body,
An electret condenser microphone unit, comprising a conductor pattern extending from a conductor pattern on the periphery of the conductor pattern and connected to an input terminal of the IC element. 5. A metal cylindrical capsule having a sound hole formed in a front plate, a conductive vibrating film arranged to face the front plate of the capsule, and a back face of the conductive vibrating film in close proximity to the back surface of the conductive vibrating film. And a back pole, and an electret polymer film formed on the front surface of the back pole so as to face the conductive vibrating membrane, a conductive tubular body that holds the back pole at the front end, and A wiring board for closing the back surface of the capsule, and an impedance conversion IC element mounted on the upper surface of the wiring board in the capsule, wherein the wiring board is a double-sided wiring board,
A peripheral conductor pattern that is in contact with the rear end surface of the holding body,
An electret condenser microphone unit, comprising a conductor pattern extending from a conductor pattern on the periphery of the conductor pattern and connected to an input terminal of the IC element.