JP2005151267A - Capacitor microphone unit and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To assemble a push-pull type capacitor microphone unit with an inexpensive part cost and with satisfactory workability by eliminating the necessity of screws and a conductive spacer. <P>SOLUTION: The push-pull type capacitor microphone unit 10A comprises first and second fixed poles 20a, 20b having the same diameter to which an electrode leading ring 22 is engaged via an electric insulating body 21 therearound; a single diaphragm 40 having a metallic film on each of both surfaces; and conductive spacers 300 disposed on each circumferential edge of both the surfaces of the diaphragm 40 oppositely to the ring 22. The first fixed pole 20a and the second fixed pole 20b are coaxially disposed oppositely to each other on both the surfaces of the diaphragm 40 via the conductive spacers 300. In this unit 10A, a conductive adhesive in which conductive particles are contained in a thermosetting composite resin is used as the conductive spacers 300. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a condenser microphone unit and a manufacturing method thereof, and more particularly to a push-pull type condenser microphone unit in which a diaphragm is disposed between a pair of fixed poles and a manufacturing method thereof.

  As described in Patent Document 1, the push-pull type condenser microphone has less input distortion and the like as compared with a single type condenser microphone having a single fixed pole, but is considerably superior in characteristics. Adjustment is difficult and expensive.

  There are various types of push-pull condenser microphones, including those described in Patent Document 1, but here, as a conventional example, a specific fixed pole (annular electrode extraction ring is formed via an electric insulator around the periphery). A microphone unit provided with a fixed pole) is described.

  FIG. 8 is a cross-sectional view showing the completed body. The microphone unit 10 is sandwiched between the first and second fixed poles 20a and 20b and a pair of conductive spacers 30 and 30 therebetween. One diaphragm (diaphragm) 40 is provided. 9A is a plan view of the first fixed pole 20a, FIG. 10B is a sectional view thereof, FIG. 10A is a plan view of the second fixed pole 20b, and FIG. The figure is shown. FIG. 11A shows a plan view of the conductive spacer 30, and FIG. 11B shows a cross-sectional view thereof.

  Both the first fixed pole 20a and the second fixed pole 20b are made of, for example, a brass disk, and a plurality of sound holes 20h for transmitting sound waves to the diaphragm 40 are formed in the disk. Around the first fixed pole 20a and the second fixed pole 20b, for example, brass electrode extraction rings 22 are fitted via electric insulators 21 made of, for example, polycarbonate.

  In this case, a female screw hole 22a is formed in the electrode lead-out ring 22 on the first fixed pole 20a side, whereas a screw insertion hole 22b is formed in the electrode lead-out ring 22 on the second fixed pole 20b side. Has been. The conductive spacer 30 is formed of, for example, a stainless steel ring body having the same diameter as the electrode extraction ring 22 and includes a plurality of screw insertion holes 30a.

  The female screw hole 22a, the screw insertion hole 22b, and the screw insertion hole 30a are arranged at the same pitch. The diaphragm 40 is a thin film in which, for example, polyethylene terephthalate (PET) or polyphenylene sulfide (PPS) is used as a base film and a metal film (for example, gold) is vapor-deposited on both surfaces thereof.

  The assembly is performed as follows. As shown in FIG. 12, the diaphragm 40 is affixed to a support ring 41 having a diameter larger than that of the fixed poles 20a and 20b, and the first fixed pole 20a and the second fixed pole are provided on both sides thereof via conductive spacers 30 and 30. The pole 20b is disposed.

  After the load is applied to the support ring 41 to adjust the tension of the diaphragm 40, the diaphragm 40 is sandwiched between the first fixed pole 20a and the second fixed pole 20b, and the screw is inserted into the second fixed pole 20b. The male screw 50 is inserted through the hole 22b and firmly tightened into the female screw hole 22a on the first fixed pole 20a side. Finally, the protruding excess portion of the diaphragm 40 is cut.

  8, the metal film on the upper surface side of the diaphragm 10 is drawn out from the upper conductive spacer 30 and the electrode lead-out ring 22 on the second fixed pole 20b side, and is connected to an impedance converter (not shown). Further, the metal film on the lower surface side is extracted from the lower conductive spacer 30 and the electrode extraction ring 22 on the first fixed pole 20a side, and is connected to another impedance converter (not shown).

Microfilm of Japanese Utility Model No. 61-56612 (Japanese Utility Model Application No. 62-169599)

  However, according to the above conventional example, there is a problem that assembly is difficult first. That is, since many screws are used, it takes time to assemble. In addition, the tension changes when a hole for passing the male screw 50 through the diaphragm 40 is opened. Moreover, since it is necessary to make a hole in the diaphragm 40, a film thickness of 6 μm or more is necessary, and a thin diaphragm cannot be used.

  Next, as another problem, expensive parts are required. The part corresponding to this is the conductive spacer 30. As described above, for example, a stainless steel ring body is used for the conductive spacer 30. However, since this requires extremely high flatness, it is necessary to prepare the ring by a method such as edging. It has become.

  Accordingly, it is an object of the present invention to eliminate the need for screws and conductive spacers in a push-pull type condenser microphone unit, so that the parts can be assembled at low cost and with good workability.

  In order to solve the above-mentioned problem, the first invention of the present application is a single sheet having first and second fixed electrodes having the same diameter with an electrode extraction ring fitted through an electric insulator in the periphery, and metal films on both surfaces. And a conductive spacer disposed opposite to the electrode extraction ring at each peripheral edge of both sides of the diaphragm, and the first diaphragm is disposed on both sides of the diaphragm via the conductive spacer. In a push-pull condenser microphone unit in which a fixed electrode and the second fixed electrode are coaxially opposed to each other, a conductive adhesive containing conductive particles in a thermosetting synthetic resin as the conductive spacer It is characterized by using materials.

  In the present invention, the conductive adhesive may be either a liquid coating type or a film. The conductive particles contained in the conductive adhesive may be metal spheres or spheres having a metal film formed on the surface of a sphere made of a synthetic resin as a nucleus.

  According to a second aspect of the present invention, in the method for manufacturing the push-pull type condenser microphone unit, a conductive material in which conductive particles are contained in a thermosetting synthetic resin on one side of the electrode extraction ring of the first fixed electrode. A first step of arranging an adhesive and the diaphragm is attached to a support ring having a diameter larger than that of the fixed pole, and is smaller in diameter than the support ring and larger in diameter than the fixed pole and has a flat surface. In a state where the tension applied to the diaphragm is adjusted by placing on the base, the first fixed electrode is placed on one surface of the diaphragm and pressed, and the diaphragm is applied by the conductive adhesive. A second step of electrically and mechanically connecting the first fixed pole and the first fixed pole; and the vibration in which the conductive adhesive is disposed on one side of the electrode lead-out ring of the second fixed pole and removed from the base Apply pressure to the other side of the plate to It is characterized in that it comprises a third step of electrically and mechanically connecting the diaphragm and the second fixed electrode by wood.

  In the second invention, after the second step or the third step, the surplus portion of the diaphragm protruding from the fixed pole is cut.

  According to the present invention, since no screwing work is required, the assembly workability can be greatly improved. In addition, since the distance between the diaphragm and the fixed electrode is ensured by the conductive particles contained in the conductive adhesive, there is no need for conductive spacers made of a metal plate with high flatness, and the cost can be reduced accordingly. Can be planned.

  In addition, since a drilling process for passing a screw through the diaphragm is not required, a thinner diaphragm can be used, and as a result, the low-frequency limit is lowered and the performance can be improved. Since screw insertion holes are not required for radial dimensions, when comparing units with the same diameter, the effective diaphragm area can be designed to be relatively large, so that sensitivity and S / N ratio can be improved. become.

  Next, embodiments of the present invention will be described with reference to FIGS. 1 to 7, but the present invention is not limited thereto. In the description of this embodiment, the same reference numerals are used for components that may be substantially the same as those of the conventional example described above.

  FIG. 1 shows a cross section of a finished product of a push-pull type condenser microphone unit 10A according to the present invention. Each component will be described according to an example of an assembly procedure. First, two fixed poles having the structure shown in FIG. 2 ((a) is a plan view and (b) is a sectional view thereof) are prepared. If one of them is the first fixed pole 20a and the other is the second fixed pole 20b, in the present invention, the first and second fixed poles 20a and 20b may have the same configuration.

  That is, the first and second fixed poles 20 a and 20 b are both made of, for example, a brass disk, and a plurality of sound holes 20 h for transmitting sound waves to the diaphragm 40 are formed in the disk. For example, brass electrode lead-out rings 22 are fitted around the first fixed pole 20a and the second fixed pole 20b via an electrical insulator 21 made of polycarbonate, for example. The electrode lead-out ring 22 need not be provided with a female screw hole or a screw insertion hole.

  Next, as shown in FIG. 3, a conductive adhesive 300 is applied to one surface of the electrode extraction ring 22 on the first fixed electrode 20 a side. The enlarged view of FIG. 7A shows a state in which the conductive adhesive 300 is applied to one surface of the electrode extraction ring 22.

  The conductive adhesive 300 is an adhesive (an anisotropic conductive adhesive) in which a large number of conductive particles 320 are mixed in a thermosetting resin 310 such as an epoxy-based resin. In this example, a liquid coating mold is used. However, a film-like conductive adhesive film can also be used.

  The conductive particles 320 may be either metal spheres or conductive resin balls having a synthetic resin sphere as a core and a metal film (for example, gold plating) formed on the surface thereof. Examples of the conductive resin ball include conductive fine particles “Micropearl AU (trade name)” manufactured by Sekisui Chemical Co., Ltd. In the present invention, the particle size of the conductive particles 320 is preferably about 0.1 mm.

  Next, as shown in FIG. 4, the diaphragm 40 is attached to the support ring 41 and placed on the base 100 having a flat surface. The diaphragm 40 is a thin film (for example, PET as an example) in which, for example, polyethylene terephthalate (PET) or polyphenylene sulfide (PPS) is used as a base film, and a metal film (for example, gold) is vapor-deposited on both sides thereof. In the present invention, it is not necessary to provide a screw insertion hole in the diaphragm 40.

  Then, in a state where a predetermined load is applied to the support ring 41 and the tension of the diaphragm 40 is adjusted, the surface of the first fixed electrode 20a to which the conductive adhesive 300 is applied is preferably opposed to the diaphragm 40 and heated. Crimp below.

  As a result, as shown in the enlarged view of FIG. 7B, the conductive particles 320 are arranged almost planarly in the thermosetting resin 310, and the distance between the diaphragm 40 and the first fixed electrode 20a is made conductive. The particle diameter of the particle 320 is specified to be, for example, 0.1 mm, and the metal film on one surface side of the diaphragm 40 and the electrode extraction ring 22 on the first fixed electrode 20a side are electrically connected via the conductive particle 320. Connected.

  The tension of the diaphragm 40 is adjusted via the support ring 41, and the support ring 41, the base 100, and the first fixed pole 20a are placed on the diaphragm 40 because the first fixed pole 20a is placed on the diaphragm 40. The size is in the order of the first fixed pole 20a <base 100 <support ring 41.

  After the thermosetting resin 310 is cured, the integrated diaphragm 40 and the first fixed pole 20a are taken out from the base 100, and as shown in FIG. 5, from the first fixed pole 20a of the diaphragm 40. Cut off the excess part that protrudes.

  Next, as shown in FIG. 6, a conductive adhesive 300 is applied to one surface of the electrode extraction ring 22 of the second fixed electrode 20 b, and the second fixed electrode 20 b is used as a support base and the second fixed electrode 20 b is used as the diaphragm 40. Crimp to the other side of

  As a result of this pressure bonding, the distance between the diaphragm 40 and the second fixed electrode 20b is regulated to 0.1 mm, which is the particle diameter of the conductive particles 320, as described above, and the diaphragm 40 is interposed via the conductive particles 320. The metal film on the other surface side and the electrode lead-out ring 22 on the second fixed pole 20b side are electrically connected to obtain a finished product of the push-pull type capacitor microphone unit 10A shown in FIG.

  As described above, the configuration of the present invention has been described together with an example of the assembling procedure. For example, the cutting of the surplus portion of the diaphragm 40 may be performed after the process of FIG. 6, or may be performed after the crimping process of FIG. You can also. In the present invention, it is not necessary to positively provide a screw insertion hole or a female screw hole in the electrode lead-out ring 22, but in the present invention, a screw insertion hole or a female screw hole is provided in the electrode lead-out ring 22. It is also applicable to.

Sectional drawing for demonstrating embodiment of the push pull type | mold condenser microphone unit by this invention. The (a) top view and (b) sectional view showing the fixed pole with which the above-mentioned condenser microphone unit is provided. Explanatory drawing which shows the assembly procedure of the said capacitor | condenser microphone unit. Explanatory drawing which shows the assembly procedure of the said capacitor | condenser microphone unit. Explanatory drawing which shows the assembly procedure of the said capacitor | condenser microphone unit. Explanatory drawing which shows the assembly procedure of the said capacitor | condenser microphone unit. In this invention, (a) The expanded sectional view which shows the state before the crimping | compression-bonding of the conductive adhesive apply | coated to the electrode extraction ring of the said fixed pole, (b) The expanded sectional view which shows the state after a crimping | compression-bonding. Sectional drawing which shows the push pull type | mold condenser microphone unit mentioned as a prior art example. The (a) top view and (b) sectional view showing the 1st fixed pole with which the above-mentioned conventional example is provided. The (a) top view and (b) sectional view showing the 2nd fixed pole with which the above-mentioned conventional example is provided. The conductive spacer with which the said prior art example is equipped, (a) Top view and (b) Sectional drawing. The exploded sectional view explaining the assembly procedure of the above-mentioned conventional example.

Explanation of symbols

10A Push-pull condenser microphone unit 20a, 20b Fixed electrode 20h Sound hole 21 Electrical insulator 22 Electrode extraction ring 40 Diaphragm 41 Support ring 100 Base 300 Conductive adhesive 310 Thermosetting resin 320 Conductive particle

Claims (5)

First and second fixed poles having the same diameter with an electrode extraction ring fitted in the periphery via an electrical insulator, one diaphragm having metal films on both surfaces, and each peripheral portion on both surfaces of the diaphragm And a conductive spacer disposed opposite to the electrode extraction ring, and the first fixed pole and the second fixed pole are coaxially opposed to both surfaces of the diaphragm via the conductive spacer. In the push-pull type condenser microphone unit,
A capacitor microphone unit characterized in that a conductive adhesive containing conductive particles in a thermosetting synthetic resin is used as the conductive spacer.   The condenser microphone unit according to claim 1, wherein the conductive adhesive is a liquid coating type.   The condenser microphone unit according to claim 1, wherein the conductive adhesive is a film. First and second fixed poles having the same diameter with an electrode extraction ring fitted in the periphery via an electrical insulator, one diaphragm having metal films on both surfaces, and each peripheral portion on both surfaces of the diaphragm And a conductive spacer disposed opposite to the electrode extraction ring, and the first fixed pole and the second fixed pole are coaxially opposed to both surfaces of the diaphragm via the conductive spacer. In the manufacturing method of the push-pull type condenser microphone unit formed,
A first step of disposing a conductive adhesive containing conductive particles in a thermosetting synthetic resin on one side of the electrode extraction ring of the first fixed electrode;
The vibration plate is affixed to a support ring having a diameter larger than that of the fixed pole, and is placed on a base having a smaller diameter than the support ring and a diameter larger than the fixed pole and having a flat surface. With the tension applied to the plate adjusted, the first fixed pole is placed on one surface of the diaphragm and pressed to electrically connect the diaphragm and the first fixed pole with the conductive adhesive. A second step of mechanically connecting;
The conductive adhesive is disposed on one surface of the electrode lead-out ring of the second fixed pole, and the other surface of the diaphragm removed from the base is pressurized and the diaphragm is connected to the diaphragm by the conductive adhesive. A third step of electrically and mechanically connecting the second fixed pole;
A method of manufacturing a condenser microphone unit.   5. The method of manufacturing a condenser microphone unit according to claim 4, wherein an excess portion of the diaphragm protruding from the fixed pole after the second step or the third step is cut.

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