JP2007081706A - Condenser microphone - Google Patents

Condenser microphone Download PDF

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Publication number
JP2007081706A
JP2007081706A JP2005265733A JP2005265733A JP2007081706A JP 2007081706 A JP2007081706 A JP 2007081706A JP 2005265733 A JP2005265733 A JP 2005265733A JP 2005265733 A JP2005265733 A JP 2005265733A JP 2007081706 A JP2007081706 A JP 2007081706A
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Japan
Prior art keywords
condenser microphone
acoustic transducer
metal case
slit
corners
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JP2005265733A
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Japanese (ja)
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JP4812378B2 (en
Inventor
Kazumoto Doi
Katsuhiro Makihata
一素 土井
勝浩 巻幡
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Matsushita Electric Ind Co Ltd
松下電器産業株式会社
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Priority to JP2005265733A priority Critical patent/JP4812378B2/en
Publication of JP2007081706A publication Critical patent/JP2007081706A/en
Application granted granted Critical
Publication of JP4812378B2 publication Critical patent/JP4812378B2/en
Application status is Expired - Fee Related legal-status Critical
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a condenser microphone suitable to be mounted on electronic equipment requiring reduction in thickness and size. <P>SOLUTION: This condenser microphone is provided with an acoustic transducer unit for converting a sound signal into an electric signal, an impedance converting unit for applying impedance conversion to the electronic signal, and a metal case for surrounding the acoustic transducer unit and the impedance converting unit. The metal case has a rectangular shape and has a slit on a side surface plate. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a condenser microphone mounted on an electronic device.

  Conventional condenser microphones generate noise when electric field noise is applied and propagated to the high-impedance part of the impedance conversion element and the same impedance as the high-impedance part inside the microphone. Need to prevent.

  Therefore, as shown in FIG. 5 (a), a slit 33 is formed on the front plate 11a of the capsule 11 in which a metal flat plate having a polymer film fused on one surface is formed into a bottomed cylindrical shape by drawing. After the polymer film is polarized and electretized, the conductive ring 37, the conductive cylindrical body 38, and the wiring substrate 39 on which the impedance conversion IC element 21 is mounted are inserted, and the rear end of the capsule 11 is caulked. A fixed microphone 100 has been proposed.

  FIG. 5B shows a slit portion viewed from the A direction in FIG. As shown in FIG. 5B, a circular recess 31 is formed at the center of the outer surface of the front plate 11a of the cylindrical capsule 11, and a ring-shaped recess 32 is formed on the inner surface of the front plate 11a. The inner diameter of the circular recess 31 is the same as the diameter of the circular recess 31 and is the same axis, and the bottom surface 32a of the ring-shaped recess 32 is located in front of the bottom surface 31a of the circular recess 31; A slit 33 is formed at a portion where the inner peripheral surface of the ring-shaped recess 32 coincides.

The diaphragm (vibration membrane) of the microphone 100 is electrically connected to the impedance conversion IC element 21 via the conductive ring 37 and the conductive cylindrical body 38, and a sound signal is transmitted via the slit 33. When input, the capacitance of the capacitor formed by the diaphragm and the front plate 11a changes and is input to the impedance conversion IC element 21 as a voltage signal, and the impedance-converted electrical signal is output via the output terminal It is.
Japanese Utility Model Publication No. 5-60079

  As described above, in the microphone described in Patent Document 1, while the sound signal is diffracted through the slit 33 and propagates to the diaphragm, the electric field noise having strong straightness is shielded by the slit 33, so that the noise is reduced. Is.

  However, in the microphone as shown in FIG. 6A, a circular recess 45 is formed on the inner surface of the front plate 11a of the capsule 11 formed into a bottomed cylindrical shape by drawing or the like, and a ring-shaped recess 46 is punched on the outer surface. The slit 33 is formed by processing or the like. However, in the recess processing, high processing accuracy is required with respect to depth and misalignment, and a large number of steps are required for processing, which is costly. Not suitable for mass production.

  In the microphone shown in FIG. 6B, the central portion of the inner surface of the front plate 11a is pushed forward and outward, a part thereof is connected in a taper shape, and the slit 47 is formed by shearing the other part. Forming. This method is not suitable for mounting on an electronic device that is required to be thin and downsized because the entire shape becomes thicker as it is pushed outward.

  In addition, as shown in FIG. 6C, in the microphone in which the central portion of the front plate 11a is pushed inward to form the slit 48, in order to avoid the protruding portion pushed inward from contacting the diaphragm, The diaphragm ring thickness needs to be larger than the protruding amount, and as a result, the microphone is enlarged. For this reason, it was not suitable for mounting on an electronic device that is required to be thin and small.

  Also, when mounting the microphone, it can be easily handled by gripping the front plate with an air pickup, but if it is sucked including the slit part during air pick, it will be formed at a position facing the front plate. The vibrating membrane may be damaged by the air pressure of the air pick, and it was difficult to handle the microphone with the air pickup.

  An object of the present invention is to provide a condenser microphone suitable for being mounted on an electronic device that is required to be thin and small. Another object of the present invention is to provide a condenser microphone that can be manufactured by simple processing that does not require high processing accuracy. Another object of the present invention is to provide a condenser microphone that can be easily handled by an air pickup.

  The condenser microphone of the present invention includes an acoustic transducer unit that converts a sound signal into an electrical signal, an impedance conversion unit that converts the impedance of the electrical signal, and a metal case that surrounds the acoustic transducer unit and the impedance conversion unit. The metal case has a square shape and has a slit in the side plate.

  With this configuration, it is not necessary to form a sound hole slit in the upper surface plate of the metal case, so that the metal case can be made thinner and smaller. In addition, since sound signals are diffracted and propagated, they pass through the slits and propagate to the acoustic transducers. On the other hand, the electric field noise is highly linear, so most of them are attenuated by the metal case without passing through the slits. The Therefore, the influence (noise) that the electric field noise has on the acoustic transducer and the impedance conversion IC installed in the metal case is reduced.

  Further, since there is no sound hole in the front plate of the metal case, there is no possibility of damaging the vibration membrane with the air pressure of the air pick, and handling with the air pickup becomes easy.

  In the condenser microphone of the present invention, the slit is opened so as not to face the acoustic transducer section.

  The condenser microphone of the present invention has the slits at the four corners of the side surface of the metal case.

  With this configuration, since electric field noise is highly linear, it is difficult to propagate to an acoustic transducer disposed at a position not facing the opening surface of the slit, and the shielding effect of the metal case is improved.

  In the condenser microphone of the present invention, the acoustic transducer part is created by a semiconductor manufacturing process.

  In the condenser microphone of the present invention, the acoustic transducer part and the impedance conversion part are formed on the same substrate.

  With this configuration, the entire condenser microphone is reduced in size and thickness, so that the mounting area of the condenser microphone can be reduced. Therefore, it can be mounted on an electronic device such as a mobile phone terminal that is required to be reduced in size and thickness.

  The method for manufacturing a condenser microphone according to the present invention includes a step of cutting four corners of a metal flat plate, and the bending of the metal flat plate into a square metal case having slits at the four corners of the side plate. And a step of installing the metal case while avoiding a direction in which the opening of the slit faces the acoustic transducer portion.

  With this configuration, the process for forming the slit can be a bending process that does not require high processing accuracy compared to the process for forming the slit in the upper surface plate of the metal case, so that the condenser microphone can be manufactured at low cost.

  The mobile phone terminal of the present invention is equipped with the condenser microphone.

  With this configuration, the mounting area required for mounting the condenser microphone is reduced, so that the mobile phone terminal can be reduced in size and thickness.

  According to the present invention, it is possible to provide a condenser microphone suitable for being mounted on an electronic device that is required to be thin and small. In addition, it is possible to provide a condenser microphone that can be manufactured by simple processing that does not require high processing accuracy. Further, it is possible to provide a condenser microphone that can be easily handled by an air pickup.

  Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
FIG. 1 is an external perspective view of a condenser microphone 1 according to the first embodiment. 2 is a cross-sectional view taken along line AA in FIG.

  As shown in FIG. 1, the condenser microphone 1 of the first embodiment includes a metal case 202 that surrounds an acoustic transducer 201 (not shown) and an impedance converter 204 (not shown).

  The metal case 202 has a square shape, and includes an upper surface plate 202a and side surface plates 202b and 202c, and slits 206 are formed at four corners.

  Next, FIG. 2 shows an AA cross-sectional view in FIG. As shown in FIG. 2, the acoustic transducer 201 is made of a silicon substrate, and includes a first electrode 201b in which a hole 201a is formed, an air gap 201d connected to the hole, and a second electrode 201c serving as a diaphragm. And is formed using MEMS technology (silicon manufacturing process).

  The second electrode 201c is electrically joined to the wiring pattern 203b installed on the wiring board 203 by wire bonding or the like, and the wiring pattern 203b is electrically joined to the input terminal 204a of the impedance conversion IC 204 by soldering or the like. .

  The output terminal 204b of the impedance conversion IC is electrically connected to the wiring board, and is connected to the wiring pattern 203c on the back surface with a through hole 203a.

  The first electrode 201b is electrically joined to the ground potential portion of the wiring pattern 203b by wire bonding or the like, and the ground potential portion of the wiring pattern 203b and the metal case 202 are electrically joined by welding or the like. .

  The input terminal 204a of the impedance conversion IC 204 can be electrically joined to the first electrode 201b. In this case, the ground of the wiring board and the second electrode 201c are electrically joined, and further the metal case 202 also needs to be electrically joined.

  FIG. 3 shows a view of the condenser microphone according to the first embodiment viewed from the direction B in FIG. As shown in FIG. 3, the acoustic transducer 201 and the impedance conversion IC 204 are arranged so as to avoid the direction facing the opening surface of the slit 206.

  When a sound signal is applied to the condenser microphone 1 formed in this manner, the sound signal is diffracted and propagates, so that it passes through the slit 206 and reaches the diaphragm of the acoustic transducer 201 regardless of the position of the sound source. Propagate. The sound signal is converted into an electric signal by the acoustic transducer 201 and the impedance conversion IC 204.

  On the other hand, the electric field noise generated around the condenser microphone is attenuated by the metal case 206. Since the electric field noise has a strong straightness, the noise influence on the acoustic transducer 201 and the impedance conversion IC 204 arranged at a position not facing the opening surface of the slit 206 is small.

  Next, a method for manufacturing the condenser microphone of the first embodiment will be described.

  First, the four corners of the metal flat plate used as the material of the metal case 202 are cut (cutting process). Next, the metal flat plate with the four corners cut is processed into a rectangular metal case 202 by bending. At this time, it is bent so as to form slits 206 at the four corners (bending step). And the said metal case is installed in the position where the opening part of the slit 206 does not oppose the acoustic transducer 201 (installation process). Through these steps, the condenser microphone of the first embodiment is manufactured.

  The acoustic transducer 201 is an acoustic-electric conversion mechanism that has been conventionally formed of a diaphragm, a spacer, and a back electrode, and is produced by a semiconductor process.

Moreover, the diaphragm in the conventional condenser microphone is formed by the second electrode 201c formed by vapor-depositing a metal film on a polymer film such as PET, PPT, or FEP. In the reflow soldering process, Although the tension is lowered and the sensitivity of the microphone may be changed, the material of the acoustic transducer in the present invention is Si and SiO 2 , and the tension does not change even at a high temperature, that is, the sensitivity does not change. Therefore, a microphone capable of reflow soldering processing can be realized.

  The condenser microphone 1 manufactured in this way has a slit formed on the side surface side, so that the overall shape does not increase. In addition, since there is no sound hole in the front plate, air pickup is possible and handling is easy.

  Conventionally, a high processing accuracy is required to form a slit in the upper surface plate of a metal case. However, according to the above-described manufacturing method, the process of forming the slit can be performed by a bending process. A condenser microphone can be manufactured at low cost without being required.

  Note that the positions where the slits are provided are not necessarily four corners as in the condenser microphone of the first embodiment shown in FIG. As shown in FIG. 4B, slits 206 may be formed at positions shifted from the four corners.

  With the configuration shown in FIG. 4B, the electric field noise propagates in the direction along the side plate 202c inside the metal case 202. Therefore, the electric field noise is near the center where the acoustic transducer and the like of the metal case 202 are arranged. Is difficult to propagate, and the shielding effect of the metal case is improved.

  In the condenser microphone 1 according to the first embodiment, since the acoustic transducer and the impedance conversion IC are both produced by a semiconductor process, they can be formed on the same wafer.

  Therefore, at this time, if AI wiring or the like is formed on the wafer, the step of electrically joining the acoustic transducer and the impedance conversion element by wire bonding or the like becomes unnecessary, and the number of steps can be reduced. A condenser microphone can be manufactured.

  Further, the number and shape of the slits are not limited to those shown in the present embodiment, and can be determined in consideration of the influence of the resonance generated in the case space on the frequency characteristics of the microphone output.

  The condenser microphone of the present invention can be manufactured by simple processing, and can be mounted on an electronic device that is required to be thin and small.

External perspective view of condenser microphone 1 of the first embodiment 1 is a cross-sectional view of the condenser microphone 1 according to the first embodiment, taken along line AA in FIG. The figure which looked at the condenser microphone 1 of this Embodiment 1 from the B direction in FIG. (A) Enlarged view of the end of the metal case of the first embodiment, (b) Modification 1 of the slit (A) Cross-sectional view of a conventional microphone, (b) A diagram showing a slit portion viewed from the direction A in FIG. (A) Conventional microphone slit shape example 1, (b) Conventional microphone slit shape example 2, (c) Conventional microphone slit shape example 3

Explanation of symbols

201 acoustic transducer 201a hole 201b first electrode 201c second electrode 201d air gap 202 metal case 202a front plate 202b, 202c side plate 203 wiring board 203a through hole 203b, 203c wiring pattern 204 impedance conversion IC
204a Input terminal 204b Output terminal 206 Slit

Claims (7)

  1. An acoustic transducer that converts sound signals into electrical signals;
    An impedance converter for impedance-converting the electrical signal;
    A metal case surrounding the acoustic transducer part and the impedance conversion part;
    The metal case is a condenser microphone having a square shape and a slit in a side plate.
  2.   The condenser microphone according to claim 1, wherein the slit is opened to avoid a direction facing the acoustic transducer unit.
  3.   The condenser microphone according to claim 1, wherein the slits are provided at four corners of the side surface of the metal case.
  4.   The condenser microphone according to any one of claims 1 to 3, wherein the acoustic transducer section is created by a semiconductor manufacturing process.
  5.   The condenser microphone according to claim 4, wherein the acoustic transducer section and the impedance conversion section are formed on the same substrate.
  6. Cutting the four corners of the metal plate;
    Processing the metal flat plate cut at the four corners by bending into a rectangular metal case having slits at the four corners of the side plate; and
    Installing the metal case avoiding the direction in which the opening of the slit faces the acoustic transducer part; and
    A method for manufacturing a condenser microphone.
  7.   A mobile phone terminal equipped with the condenser microphone according to claim 1.
JP2005265733A 2005-09-13 2005-09-13 Condenser microphone Expired - Fee Related JP4812378B2 (en)

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JP2005265733A JP4812378B2 (en) 2005-09-13 2005-09-13 Condenser microphone

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Application Number Priority Date Filing Date Title
JP2005265733A JP4812378B2 (en) 2005-09-13 2005-09-13 Condenser microphone

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JP2007081706A true JP2007081706A (en) 2007-03-29
JP4812378B2 JP4812378B2 (en) 2011-11-09

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008245111A (en) * 2007-03-28 2008-10-09 Matsushita Electric Ind Co Ltd Microphone, method for assembling electronic equipment using the microphone, and portable terminal
JP2012175384A (en) * 2011-02-21 2012-09-10 Sony Corp Microphone, connector unit, pin plug holder and method of manufacturing pin plug holder
JP2014099789A (en) * 2012-11-15 2014-05-29 Nec Access Technica Ltd Microphone and mounting structure of the same

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5514361A (en) * 1978-07-18 1980-01-31 Diesel Kiki Co Ltd Proportional control type remote directional control valve device
JPH0262600A (en) * 1988-08-29 1990-03-02 Matsushita Electric Ind Co Ltd Electromagnetic type sounding body
JP2004537182A (en) * 2000-11-28 2004-12-09 ノウレス エレクトロニクス, リミテッド ライアビリティ カンパニー Small silicon condenser microphone and method of manufacturing the same

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5514361A (en) * 1978-07-18 1980-01-31 Diesel Kiki Co Ltd Proportional control type remote directional control valve device
JPH0262600A (en) * 1988-08-29 1990-03-02 Matsushita Electric Ind Co Ltd Electromagnetic type sounding body
JP2004537182A (en) * 2000-11-28 2004-12-09 ノウレス エレクトロニクス, リミテッド ライアビリティ カンパニー Small silicon condenser microphone and method of manufacturing the same

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008245111A (en) * 2007-03-28 2008-10-09 Matsushita Electric Ind Co Ltd Microphone, method for assembling electronic equipment using the microphone, and portable terminal
JP2012175384A (en) * 2011-02-21 2012-09-10 Sony Corp Microphone, connector unit, pin plug holder and method of manufacturing pin plug holder
JP2014099789A (en) * 2012-11-15 2014-05-29 Nec Access Technica Ltd Microphone and mounting structure of the same

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Publication number Publication date
JP4812378B2 (en) 2011-11-09

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