JP3609031B2 - Condenser microphone - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention provides a condenser in which a microphone unit having a sound hole formed in an end wall is housed in a holder having an acoustic intake portion formed in the end wall, and a filter is disposed at a position covering the sound hole. It relates to a microphone.
[0002]
[Prior art]
As a condenser microphone configured as described above, there is a condenser microphone disclosed in Japanese Patent Application Laid-Open No. 11-55795, and this condenser microphone has an electret inside a cylindrical capsule made of an aluminum material having a sound hole formed in an end wall. A microphone unit is configured by housing the diaphragm, back electrode, insulating substrate, impedance conversion element, etc., and a dust-proof film (filter) is placed on the entire end wall of the cylindrical capsule to cover the sound hole of the cylindrical capsule. In addition, a case (holder) in which an opening is formed in the end wall is made of a synthetic resin material, and a cylindrical capsule is built in the case.
[0003]
[Problems to be solved by the invention]
The condenser microphone cited as the prior art is arranged so that the dust-proof film covers the entire outer surface of the end wall of the cylindrical capsule, so that when the cylindrical capsule is housed in the case, the outer wall of the end wall of the cylindrical capsule The outer peripheral portion of the dust-proof film is sandwiched between the inner surface of the end wall of the case, and the front surface of the end wall of the cylindrical capsule is separated from the inner surface of the case end wall by the thickness of the dust-proof film. For this reason, the conventional technique requires a space for arranging a dust-proof film between the inner surface of the end wall of the case and the outer surface of the end wall of the cylindrical capsule, and in a direction orthogonal to the respective end walls. As a result, the size of the microphone was increased and the miniaturization of the microphone was hindered.
[0004]
Therefore, it is conceivable to reduce the size of the microphone using a thin dust-proof film, but the dust-proof film allows the propagation of sound through a space that allows air flow, such as a non-woven fabric, while allowing dust and water droplets to enter. Since it is provided for the purpose of blocking, it is not preferable to use a material that is too thin, as it will reduce the dustproof, dripproof, or acoustic performance.
[0005]
An object of the present invention is to reduce the size of a condenser microphone having a structure in which a microphone unit is housed in a holder without deteriorating the performance of a filter.
[0006]
[Means for Solving the Problems]
The features, functions and effects of the condenser microphone according to claim 1 of the present invention are as follows.
〔Characteristic〕
In the condenser microphone in which the microphone unit in which the sound hole is formed in the end wall is housed in the holder in which the sound capturing portion is formed in the end wall, and the filter is disposed at a position covering the sound hole. A space in which an acoustic intake portion is configured to include the filter integrated with an end wall of the holder, the holder is manufactured by resin molding, and allows air to flow between fibers as the filter. Is used, and this filter is integrated with the holder by inserting the filter at the time of molding the holder .
[0007]
[Action / Effect]
According to the above feature, since the filter is integrated with the holder, there is no need to attach the filter even when the microphone unit is housed in the holder, and the filter is made of an inexpensive and easily available material such as cloth. It is also possible. As a result, a compact condenser microphone that can reduce the cost without degrading the performance of the filter has been constructed.
[0008]
The features, functions and effects of the condenser microphone according to claim 2 of the present invention are as follows.
〔Characteristic〕
2. The condenser microphone according to claim 1, wherein the holder includes a front holder provided with the filter and a rear holder that can be connected to and separated from the front holder. The microphone unit is housed in a space formed by
[0009]
[Action / Effect]
According to the above feature, the microphone unit can be housed in a form sandwiched between the front holder and the rear holder, and the microphone can be assembled by fitting and connecting the front holder and the rear holder.
[0010]
The characteristics, operation and effect of the condenser microphone according to claim 3 of the present invention are as follows.
〔Characteristic〕
3. The condenser microphone according to claim 2 , wherein an electrode pattern is formed on a rear surface of the microphone unit, and a terminal for taking out a signal by contacting the electrode pattern is provided in the rear holder .
[0011]
[Action / Effect]
According to the above feature, when the microphone is assembled by fitting and connecting the front holder and the rear holder, the terminal provided on the rear holder can contact the electrode pattern formed on the rear surface of the microphone unit and take out the signal. It becomes.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a first embodiment of the invention will be described with reference to the drawings.
[First Embodiment]
As shown in FIGS. 1 to 6, a microphone unit U having a metal case 10 is housed in a tightly fitting state inside a resin holder H, and a sound hole formed in the case 10 A condenser microphone is configured by disposing a filter F at a position covering 11 for the purpose of dust proofing and drip proofing, high frequency correction of frequency characteristics, directivity adjustment, and use as an acoustic resistance material. This condenser microphone is used for a device such as a mobile phone or a tape recorder that requires a reduction in size.
[0017]
The holder H is formed by forming an opening 1 as an acoustic take-in portion in the front end wall HA and attaching a center terminal 2 and a side terminal 3 to the rear end wall. This holder H has an insulating property, and is formed by molding a material such as styrene butadiene rubber (SBR) or nitrile rubber (NBR) so that the cross-sectional shape becomes a ring shape, and when an external force is applied. The microphone unit U is well protected by elastic deformation. The center terminal 2 and the side terminal 3 are respectively provided with conducting pieces 2C and 3C made of a good conductor protruding and urged by springs 2B and 3B with respect to cylindrical cases 2A and 3A made of a good conductor such as a copper alloy. ing.
[0018]
The microphone unit U includes the case 10 formed into a cylindrical shape having a front end wall 10A by pressing an aluminum plate, and a sound hole 11 is formed in the front end wall 10A. And inside this case 10, electrode ring 12, electret diaphragm 13, ring-shaped spacer 14, back pole 15 made of a good conductor such as copper or copper alloy, insulating ring 16, impedance conversion element 17 having FET, Each insulating substrate 18 that supports the impedance element 17 is accommodated. The insulating substrate 18 is fixed by bending the rear end side of the case 10. The case 10 can also be configured using a good conductor that is easy to process, such as a copper alloy or a silver alloy.
[0019]
In this microphone unit U, the electret diaphragm 13 and the case 10 are electrically connected by the contact structure via the electrode ring 12, and the back electrode 15 and the electrode 17 </ b> A projecting from the impedance conversion element 17 are in contact with each other. These are electrically conducting, and a terminal (not shown) of the impedance conversion element 17 and an electrode pattern conducting with the case 10 are formed on the rear surface of the insulating substrate 18. Further, as shown in FIG. 6, this electrode pattern is composed of a center pattern 19 at the center position of the insulating substrate 18 and a ring pattern 20 with the center pattern 19 as the center. The conductive piece 2 </ b> C is brought into contact conduction, and the conductive piece 3 </ b> C of the side terminal 3 is brought into contact conduction with the ring pattern 20.
[0020]
The filter F is sized to fit into the opening 1 of the holder H, and is molded to a thickness that substantially matches the thickness of the front end wall HA of the holder H, and the front end wall 10A of the case 10 with an adhesive (not shown). It is fixed to. That is, this filter F uses a nonwoven fabric or a cloth as a woven fabric as a representative material in which a space allowing air to flow between fibers is formed, and the outer surface of the front end wall 10A of the case 10 is shown in FIG. As shown, a pressure-sensitive adhesive is applied to a ring-shaped region E (region surrounded by a broken line in FIG. 3) excluding the sound hole 11, and is adhered and fixed by the adhesive force of this pressure-sensitive adhesive material. Further, in the first embodiment, the filter F is made of a material having a thickness that substantially matches the front end wall HA of the holder H. However, the present invention is not limited as long as the condenser microphone can be miniaturized. The material of such a thickness that the front surface of the filter F protrudes slightly from the front end wall HA of the holder H is allowed.
[0021]
With this configuration, when manufacturing the condenser microphone, as described above, the microphone unit U is assembled by setting the electret diaphragm 13 and the back pole 15 in the case 10, and the front end wall of the case 10 is assembled. An adhesive is applied to 10A, and a filter F is applied and fixed. Thereafter, the condenser microphone is completed by forcibly expanding the opening 1 of the holder H and inserting the microphone unit U into the holder. In this completed state, the outer surface of the front end wall 10A of the case 10 of the microphone unit U is in close contact with the inner surface of the front end wall HA of the holder H, and the filter F provided on the outer surface of the front end wall 10A of the case 10 is the opening of the holder H. 1, the position of the front surface of the filter F substantially coincides with the position of the surface of the front end wall HA of the holder H. When the microphone unit U is inserted into the holder in this way, the conductive piece 2C of the center terminal 2 is brought into contact with the center pattern 19, and the conductive piece 3C of the side terminal 3 is connected to the ring pattern 20. Are brought into contact with each other and a signal can be taken out through the center terminal 2 and the side terminal 3.
[0022]
Since it comprised in this way, in the capacitor | condenser microphone of 1st Embodiment, when the filter F fits in the opening 1 of the holder H, use of the filter F of the thickness substantially corresponded with the thickness of the front end wall HA of the holder H is used. Compared with the prior art, the inner surface of the front end wall HA of the holder H and the outer surface of the front end wall 10A of the case 10 of the microphone unit U are brought into close contact with each of the end walls HA, 10A. The size of the condenser microphone can be reduced by reducing the dimensions in the orthogonal direction. In addition, in the first embodiment, the filter F is fixed to the case 10 using an adhesive, so that the adhesive is absorbed into the filter F by capillary action as in the case of using a liquid adhesive. Therefore, the acoustic performance is not deteriorated, and the use of an inexpensive cloth as the filter F enables a reduction in cost.
[0023]
Hereinafter, a second embodiment of the present invention will be described with reference to the drawings.
[Second Embodiment]
In the second embodiment, those having the same functions as those of the first embodiment are given the same numbers and symbols as those of the first embodiment.
[0024]
In the second embodiment, the structure of the microphone unit U is basically unchanged, and the holder H is composed of a front holder 5 and a rear holder 6 that can be connected and separated, and the front end of the front holder 5 The second embodiment is different from the first embodiment in that the filter F is provided integrally with the wall HA. In other words, the rear end of the front holder 5 and the front end of the rear holder 6 are formed with a fitting connection portion for connecting them, and can be connected and separated. As a representative material in which a space allowing distribution is formed, a non-woven fabric or a fabric as a woven fabric is used. When the holder H is molded, the filter F is inserted into the front end wall HA of the front holder 5 to generate sound. The intake part is configured.
[0025]
The filter F is made of a material having a thickness that substantially matches the thickness of the front end wall HA of the front holder 5. The front surface of the filter F is made to substantially match the front surface of the front end wall HA of the front holder 5. The rear surface is made to substantially coincide with the rear surface of the front end wall HA of the front holder 5. In addition, the present invention allows the use of a material having a thickness such that the front surface of the filter F slightly protrudes from the front end wall HA of the holder H as long as the miniaturization of the condenser microphone is promoted. .
[0026]
With this configuration, when manufacturing a condenser microphone, the microphone unit U is assembled in the same manner as in the first embodiment, and the front holder 5 with the filter F inserted therein, the center terminal 2 and the side terminals 3. The microphone unit U is stored between the rear holder 6 and the rear holder 6 so that the front holder 5 and the rear holder 6 are brought into a fitted state, thereby completing the condenser microphone. In this completed state, the front surface of the microphone unit U is in close contact with the inner surface of the front end wall HA of the front holder 5, and the center pattern 19 and the ring pattern 20 of the insulating substrate 18 of the microphone unit U are centered on the rear holder 6. The conductive pieces 2C and 3C of the terminal 2 and the side terminal 3 are brought into contact with each other, and a signal can be taken out through the center terminal 2 and the side terminal 3.
[0027]
With this configuration, in the condenser microphone according to the second embodiment, not only the trouble of attaching the filter F is eliminated and the assembly is facilitated, but also the inner surface of the front end wall HA of the holder H and the microphone unit U The outer surface of the front end wall 10A of the case 10 is brought into close contact with each other so that the dimensions can be shortened in the direction orthogonal to the end walls HA and 10A, thereby enabling the miniaturization of the condenser microphone. In addition, by using an inexpensive cloth as the filter F, the cost can be reduced.
[0028]
In particular, in the first and second embodiments, the electret diaphragm is used. However, the electret diaphragm is not used, and a capacitor that applies a DC bias voltage between the diaphragm and the back electrode is used. It is also possible to apply to a microphone. Further, the present invention prevents the use of connecting members such as using small rivets when fixing the filter F to the front end wall 10A of the case 10 corresponding to the first embodiment. In correspondence with the second embodiment, a resin or metal ring is set in advance on the outer periphery of the filter F, and the filter F is inserted into the holder H integrally with the ring. In the form in which the holder H and the filter F are integrated by fitting and fixing the filter F to the formed opening, or by fixing the filter F to the opening of the holder H using an adhesive. It does not prevent implementation.
[Brief description of the drawings]
FIG. 1 is a perspective view of a condenser microphone according to a first embodiment. FIG. 2 is a sectional view of the condenser microphone according to the first embodiment. FIG. 3 is an exploded perspective view of the condenser microphone according to the first embodiment. 4 is a plan view of the condenser microphone according to the first embodiment. FIG. 5 is a bottom view of the condenser microphone according to the first embodiment. FIG. 6 is a diagram showing an electrode pattern according to the first embodiment. FIG. 8 is a cross-sectional view of a condenser microphone according to a second embodiment. FIG. 8 is an exploded perspective view of the condenser microphone according to the second embodiment.
1 Opening 11 Sound hole F Filter H Holder HA End wall U Microphone unit

Claims (3)

A condenser microphone in which a microphone unit in which a sound hole is formed in an end wall is housed in a holder in which an acoustic capture portion is formed in an end wall, and a filter is disposed at a position covering the sound hole. ,
The acoustic intake portion includes the filter integrated with the end wall of the holder, and the holder is manufactured by resin molding to allow air to flow between fibers as the filter. A condenser microphone that uses a material in which a space is formed and is integrated with the holder by inserting this filter when the holder is molded . The holder includes a front holder provided with the filter and a rear holder that can be connected to and separated from the front holder, and the microphone is formed in a space formed by the front holder and the rear holder. 2. The condenser microphone according to claim 1, wherein the unit is housed . 3. The condenser microphone according to claim 2, wherein an electrode pattern is formed on a rear surface of the microphone unit, and a terminal for taking out a signal by contacting the electrode pattern is provided in the rear holder .

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