JP2010050869A - Capacitor microphone unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To connect a fixed pole and a drawing electrode, without fail by a simple work, without noise due to external vibrations being generated and without adversely affecting directional frequency response. <P>SOLUTION: The capacitor microphone unit includes: a diaphragm 21; a fixed pole 23 facing the diaphragm 21; an insulating seat 24 which supports the fixed pole 23 on the side of one end part, has a rear air chamber 242 of a prescribed volume formed on the back surface side of the fixed pole 23, and is provided with a through-hole 244 communicated with the back air chamber 242 on the side of the other end part; and a drawing electrode 25, forcibly fitted to the through-hole 244. In the capacitor microphone unit in which the fixed pole 23 and the drawing electrode 25 are electrically connected by a conducting means, provided inside the back air chamber 242 as a conducting means, a belt-like leaf spring 50 is used, whose one end 50a is in contact with the drawing electrode 25 inside the through-hole 244, and other end 50b is in elastic contact with the back surface side of the fixed pole 23. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a condenser microphone unit, and more particularly to a conduction means for electrically connecting a fixed electrode and an extraction electrode.

  As shown in FIG. 3, the condenser microphone unit is basically a cylindrical unit made of a metal material having a front acoustic terminal 11 on one end face side and an open end 12 on the other end face side. A case 10 and an electrostatic acoustoelectric transducer 20 accommodated in the unit case 10 are provided.

  The acoustoelectric transducer 20 includes a diaphragm 21 stretched on a support ring (diaphragm ring) 22 with a predetermined tension, and a fixed pole 23 supported on an insulating seat 24, opposed to each other via a spacer ring 25. It is composed by doing.

  In this example, the acoustoelectric converter 20 is housed in the unit case 10 and then pressed and fixed by the lock ring 13 screwed into the opening 12 of the unit case 10. In many cases, the acoustoelectric converter 20 is pressed and fixed by caulking of the opening edge of the unit case 10.

  Referring also to FIG. 4, the insulating seat 24 is made of a synthetic resin material, and a concave portion 241 into which the fixed electrode 23 is press-fitted is formed on one end portion side thereof. In the insulating seat 24, a back air chamber 242 having a predetermined volume is provided on the back side of the fixed electrode 23.

  A cylindrical portion 243 having a through hole 244 communicating with the back air chamber 242 is integrally formed on the other end side of the insulating seat 24, and the drawer is electrically connected to the fixed pole 23 to the cylindrical portion 243. The electrode 25 is fitted.

  The diaphragm 21 is vibrated by the incoming sound wave, thereby changing the capacitance between the fixed pole 23 and the diaphragm 21. A signal corresponding to the change in capacitance is output from the fixed pole 23. Since the output impedance is extremely high, a low impedance audio signal is obtained through the impedance converter 30 in the condenser microphone unit. Yes.

  Normally, an FET (field effect transistor) is used for the impedance converter 30, but a vacuum tube may be adopted in rare cases.

  In this example, the impedance converter 30 is mounted on a circuit board 31 on the microphone body side (not shown), and the gate terminal 30a of the impedance converter 30 is connected to the extraction electrode 25 when connecting the condenser microphone unit to the microphone body. Contact.

  The fixed electrode 23 and the extraction electrode 25 are connected via a predetermined electric wiring system. Since the connection portion has high electrical impedance, noise (different noise) is caused by the vibration of the connection portion due to external vibration. Sound) may occur.

  In order to eliminate this point, in the invention described in Patent Document 1, as shown in FIG. 3, the fixed electrode 23 and the extraction electrode 25 are electrically connected by a ribbon foil 40 made of a metal foil such as aluminum that is plastically deformed. I try to connect.

  Here, an example of the connection work by the ribbon foil 40 will be described with reference to FIGS. First, as shown in FIG. 4A, the ribbon foil 40 cut slightly longer is passed from the back air chamber 242 of the insulating seat 24 into the through hole 244.

  Next, as shown in FIG. 4B, the extraction electrode 25 is press-fitted into the through hole 244 (forced fitting), and the one end 40 a side of the ribbon foil 40 is fixed in the through hole 244.

  Thereafter, as shown in FIG. 4C, the fixed pole 23 is press-fitted into the recess 241 of the insulating seat 24, and the other end 40 b side of the ribbon foil 40 is placed on the outer peripheral surface of the fixed pole 23 and the inner peripheral surface of the recess 241. The excess portion that is sandwiched between the two and protruding outside is cut with a cutter or the like.

Japanese Utility Model Publication No. 04-50995

  According to the invention described in Patent Document 1, since the ribbon foil 40 is plastically deformed and does not vibrate due to external vibration, noise (abnormal noise) due to vibration hardly occurs, but the following problems to be solved The point is left.

  That is, since the other end side 40b of the ribbon foil 40 is sandwiched between the outer peripheral surface of the fixed pole 23 and the inner peripheral surface of the concave portion 241, the concave portion 241 of the insulating seat 24 is deformed by the thickness of the ribbon foil 40, There is a slight gap.

  If it does so, the air which exists between the diaphragm 21 and the fixed pole 23 will leak from the clearance gap. This air leakage causes deterioration of the directional frequency response particularly in the case of a unit having a high mechanical impedance such as a microphone unit used in a narrow directivity microphone.

  Further, in terms of workability, it is necessary to cut the surplus ribbon foil with a cutter or the like. In addition, if cutting is inappropriate and a protruding portion is left particularly on the other end 40b side, the remaining portion may contact (short-circuit) the unit case 10 and an audio signal may not be output.

  Accordingly, the problem of the present invention is that noise (abnormal noise) due to external vibration does not occur when the fixed pole and the extraction electrode are electrically connected, and the directional frequency response is not adversely affected. The purpose is to enable the fixed electrode and the extraction electrode to be reliably connected by a simple operation.

  In order to solve the above-mentioned problems, the present invention provides a diaphragm stretched on a support ring, a fixed pole disposed opposite to the diaphragm via a spacer ring, and supports the fixed pole on one end side. An insulating seat having a back air chamber having a predetermined volume on the back side of the fixed electrode and having a through hole communicating with the back air chamber on the other end side, and an extraction electrode forcedly fitted into the through hole In the condenser microphone unit in which the fixed electrode and the extraction electrode are electrically connected by the conduction means provided in the back air chamber, one end is provided in the through hole as the conduction means. A belt-shaped leaf spring is used, which is in contact with the extraction electrode and whose other end elastically contacts the back side of the fixed pole.

  In the present invention, it is preferable that an elastic body that presses the leaf spring against the inner wall surface of the through hole is fitted into the through hole.

  According to the present invention, the conductive means for electrically connecting the fixed electrode and the extraction electrode has a belt-like shape in which one end is in contact with the extraction electrode in the through hole and the other end is elastically in contact with the back side of the fixed electrode. By using a leaf spring, first, noise (abnormal noise) due to external vibration does not occur, and secondly, the concave portion into which the fixed pole of the insulating seat is press-fitted does not deform. Deterioration of the directivity frequency response is prevented, and thirdly, there is an effect that the cutting work is unnecessary and the workability is improved, and there is no possibility that the leaf spring comes into contact with the unit case.

  Also, by fitting an elastic body that presses the plate spring against the inner wall surface of the through hole in the through hole, the plate spring is braked by the elastic body, so that noise (abnormal noise) due to external vibration is further generated. It can be surely prevented.

  Next, an embodiment of the present invention will be described with reference to FIGS. 1 and 2, but the present invention is not limited to this. FIG. 1 is a longitudinal sectional view showing a condenser microphone unit according to the embodiment, FIG. 2 (a) is an exploded sectional view on the fixed pole side, and FIGS. 2 (b) and 2 (c) are explanatory views showing a connection work process. It should be noted that substantially the same components as those of the condenser microphone unit described as the conventional example in FIG.

  Referring to FIG. 1, the condenser microphone unit according to this embodiment also has a front acoustic terminal 11 on one end surface side as a basic configuration, similar to the condenser microphone unit described in FIG. A cylindrical unit case 10 made of a metal material whose end face side is opened as an opening 12 and an electrostatic acoustoelectric transducer 20 housed in the unit case 10 are provided.

  The acoustoelectric transducer 20 includes a diaphragm 21 stretched on a support ring (diaphragm ring) 22 with a predetermined tension, and a fixed pole 23 supported on an insulating seat 24, opposed to each other via a spacer ring 25. It is composed by doing.

  In this embodiment, the unit case 10 is made of a highly rigid metal material such as a brass alloy, and the acoustoelectric converter 20 is housed in the unit case 10 and then screwed into the opening 12 of the unit case 10. Although it is pressed and fixed by the lock ring 13, the unit case 10 may be made of, for example, aluminum which is easily caulked, and the acoustoelectric converter 20 may be pressed and fixed by caulking the opening edge of the unit case 10.

  Referring also to FIG. 2A, the insulating seat 24 is made of a synthetic resin material, and a concave portion 241 into which the fixed electrode 23 is press-fitted is formed on one end portion side thereof. In the insulating seat 24, a back air chamber 242 having a predetermined volume is provided on the back side of the fixed electrode 23.

  A cylindrical portion 243 having a through hole 244 communicating with the back air chamber 242 is integrally formed on the other end side of the insulating seat 24, and the drawer is electrically connected to the fixed pole 23 to the cylindrical portion 243. The electrode 25 is fitted. As shown in FIG. 1, the gate terminal 30 a of the impedance converter 30 is in contact with the extraction electrode 25.

  In this embodiment, the impedance converter 30 is mounted on a circuit board 31 on the microphone body side (not shown). When the condenser microphone unit is connected to the microphone body, the gate terminal 30a of the impedance converter 30 is connected to the extraction electrode 25. Unlike this, the impedance converter 30 may be provided in the condenser microphone unit.

  Normally, an FET (field effect transistor) is used for the impedance converter 30, but a vacuum tube may be adopted in rare cases.

  In the present invention, the fixed electrode 23 and the extraction electrode 25 are electrically connected via a leaf spring 50 formed in a strip shape (strip shape).

  As shown in FIG. 1, the leaf spring 50 is disposed from the back air chamber 242 to the inside of the through hole 244, and the fixed electrode 23 and the extraction electrode 25 at the time of assembly so as to elastically contact the fixed electrode 23. Has a length longer than the distance between the two.

  When assembling, first, as shown in FIG. 2B, the extraction electrode 25 is press-fitted (forced fitting) into the through hole 244 from the lower end of the cylindrical portion 243, and one end of the leaf spring 50 is inserted from the back air chamber 242 side. The 50a side is inserted into the through hole 244 and brought into contact with the extraction electrode 25.

  In this state, the elastic body 60 is pushed into the through hole 244 from the back air chamber 242 side, and the leaf spring 60 is pressed against the inner wall surface of the through hole 244 by the elastic body 60 to fix the plate spring 60. A rubber elastic body having a diameter larger than that of the through hole 244 may be used for the elastic body 60.

  Next, as shown in FIG. 2C, the fixed pole 23 is press-fitted into the recess 241 of the insulating seat 24. As a result, the other end 50 b side of the leaf spring 60 is curved and elastically contacts the back surface of the fixed pole 23.

  Due to the reaction force, one end 50a of the leaf spring 50 comes into contact with the extraction electrode 25 more strongly, and the elastic body 60 is also compressed along with the deformation of the leaf spring 50, and the leaf spring 50 is mechanically braked against vibration. .

  Thus, according to the present invention, the fixed pole 23 and the extraction electrode 25 are securely connected via the leaf spring 50. Since there is nothing sandwiched between the fixed electrode 23 and the recess 241, air leakage due to the distortion of the recess 241 does not occur.

  Further, since the leaf spring 50 is mechanically braked by the elastic body 60, it does not vibrate due to external vibration, thereby reliably preventing abnormal noise caused by the vibration. Furthermore, the operation | work which cut | disconnects an edge part like the ribbon foil used conventionally is unnecessary, and while the workability | operativity is improved, the accident which short-circuits with the unit case 10 does not generate | occur | produce.

1 is a longitudinal sectional view showing a condenser microphone unit according to an embodiment of the present invention. (A) Exploded sectional view of fixed pole side, (b), (c) Explanatory drawing showing connection work process. The longitudinal cross-sectional view which shows the conventional condenser microphone unit. (A)-(c) Explanatory drawing which shows the connection work process by the conventional ribbon foil.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Unit case 11 Front acoustic terminal 12 Opening part 20 Acoustoelectric converter 21 Diaphragm 22 Support ring 23 Fixed pole 24 Insulating seat 241 Recess 242 Back air chamber 243 Cylindrical part 244 Through-hole 25 Extraction electrode 30 Impedance converter (FET)
31 circuit board 50 leaf spring 60 elastic body

Claims (2)

A diaphragm stretched on a support ring, a fixed pole disposed opposite to the diaphragm via a spacer ring, the fixed pole supported on one end side, and a predetermined volume on the back side of the fixed pole A back air chamber is formed, an insulating seat having a through hole communicating with the back air chamber on the other end side, and an extraction electrode forcedly fitted into the through hole, the fixed electrode and the extraction electrode In the condenser microphone unit that is electrically connected by the conduction means provided in the back air chamber,
A condenser microphone unit characterized in that a strip-like leaf spring is used as the conducting means, one end of which is in contact with the extraction electrode in the through hole and the other end of which is elastically in contact with the back side of the fixed pole.   The condenser microphone unit according to claim 1, wherein an elastic body that presses the leaf spring against the inner wall surface of the through hole is fitted in the through hole.

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