JP4958159B2 - Microphone unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a microphone unit where an acoustic resistance material can be arranged without varying a previously set predetermined acoustic resistance value. <P>SOLUTION: The microphone unit 11 which at least has the acoustic resistance material 52 closing a communication hole 47 formed at an insulating seat 42 which has, at least on one side face thereof, a large-diameter recessed portion 44 linked to the communication hole 47 and a small-diameter recessed portion 45 connected to the large-diameter recessed portion 44 while having a step. The small-diameter recessed portion 45 has an outside inner bottom 46a and an inside inner bottom 46b formed by partitioning an inner bottom 46 by an annular projection 48. In an inner bottom 46b, the acoustic resistance material 52 is disposed and an elastic material 53 which is normally larger in sitting height than the annular projection 48 is disposed. In the small-diameter recessed portion 44, on the other hand, a support member 55 supported by the annular projection 48 is disposed to freely press the elastic material 53. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention relates to a microphone unit that can arrange an acoustic resistance material without changing a predetermined acoustic resistance value set in advance.

  Some microphone units are provided with an acoustic resistance material in the sound path so that directivity can be controlled by adjusting sound waves entering from the side or rear. In this case, the acoustic resistance material is selectively used depending on the desired purpose, such as a thin sheet-like material such as woven fabric, non-woven fabric or nylon mesh, or a thick sponge-like material. Yes.

  Among these, the acoustic resistance material formed in the form of a sheet is generally arranged by sticking to a support member provided with a sound-permeable opening using a double-sided tape or an adhesive so as to cover the opening. Has been.

  However, when an adhesive or a double-sided tape is used, the adhesive component may penetrate into the mesh of the sheet-like acoustic resistance material and change the acoustic resistance value. For this reason, for each microphone unit, adjustment of an acoustic resistance value and aging processing are required.

On the other hand, in the microphone unit, for the purpose of making the adjustment of the acoustic resistance value and the aging treatment unnecessary, for example, an acoustic resistance material is used without using a double-sided tape or an adhesive as disclosed in Patent Document 1 below. There has already been proposed a structure in which the support member is mechanically clamped.
Japanese Utility Model Publication No. 7-29996

  FIG. 3 is a longitudinal sectional view of the acoustic transducer (microphone unit) disclosed in Patent Document 1. According to the figure, a condenser-type microphone unit 1 having a cylindrical outer shape is provided with a circular sheet-like acoustic resistance material 4 in an air chamber 3 secured on the back side of a back electrode plate 2. Is formed.

  The acoustic resistance material 4 is formed using a nylon mesh sheet, and has a through-hole 9 that functions as a sound path in a state of being overlaid integrally with a sponge material 5 having both elasticity and air permeability. , 9 are sandwiched and fixed between a first support member 6 and a second support member 7 provided separately.

  In this case, the one-side support member 6 positioned on the capacitor portion side is hooked on a step portion 2 a provided on the inner peripheral surface of the back electrode plate 2 that defines the air chamber 3. The other side support member 7 that contacts the sponge material 5 is supported by a ring member 8 that is screwed into the inner peripheral surface of the back electrode plate 2. Thereby, the acoustic resistance material 4 and the sponge material 5 are sandwiched and fixed integrally between the one-side support member 6 and the other-side support member 7.

  Further, the ring member 8 can be strongly compressed by screwing and tightening the ring member 8 so as to pressurize the sponge material 5 side, thereby strongly compressing the contact portion with the other side support member 7 of the sponge material 5. As described above, the acoustic resistance material 4 integrated with the sponge material 5 can be elastically adhered to the one-side support member 6 along with the contact surface with the one-side support member 6. All air leakage does not occur and the predetermined acoustic resistance value is fixed without being changed.

  In this way, each microphone unit 1 to which the acoustic resistance material 4 is fixed does not cause variation in acoustic resistance value among the individual units. As a result, performance such as directivity characteristics and sensitivity can be stabilized and produced in large quantities. .

  By the way, according to the microphone unit 1 shown in FIG. 3, the sheet-like acoustic resistance material 4 can be arranged without changing the acoustic resistance value. However, since the sponge material 5 integrated with the acoustic resistance material 4 itself has an acoustic resistance function, the acoustic resistance value changes depending on the degree of compression. As a result, time and labor are allocated to the adjustment work. There was an inconvenience that had to be done.

  Furthermore, the one side support member 6 must be separately added together with the other side support member 7, unlike the constituent member which the microphone unit 1 is essential. For this reason, the microphone unit 1 has a large number of members and a complicated structure, which makes it difficult to dispose two or more acoustic resistance materials 4.

  An object of the present invention is to provide a microphone unit in which a sheet-like acoustic resistance material can be disposed without changing a predetermined acoustic resistance value set in advance, in view of the above-described problems of the prior art. is there.

  The present invention has been made to achieve the above object, and in the microphone unit comprising at least an acoustic resistance material for closing the communication hole provided in the insulating seat, the insulating seat has the communication surface at least on one side surface thereof. A large-diameter concave portion communicated with the hole, and a small-diameter concave portion that is continuous with the large-diameter concave portion with a step, and the small-diameter concave portion is an outer deep bottom portion that is partitioned by an annular protrusion. And an inner back bottom, the acoustic resistance material is disposed in the inner back bottom, and an elastic material having a seat height higher than that of the annular protrusion is disposed in a normal state. The most important feature is that a support member supported via the annular protrusion is disposed so as to freely press the elastic member.

  In this case, a capacitor portion composed of a support ring on which the diaphragm is stretched, and a back electrode plate that is disposed to face the diaphragm with a predetermined gap therebetween is provided on each side of the insulating seat. It is preferable to use a double-sided type that is provided separately.

  According to the first aspect of the present invention, since the acoustic resistance material can be disposed without using an adhesive, the sound caused by the penetration of the adhesive component or the leakage of air along the contact surface with the support member. The through hole can be covered without causing a change in the resistance value. Therefore, each microphone unit can be mass-produced with uniform performance including frequency characteristics and sensitivity by eliminating the need for individual post-adjustment of the acoustic resistance value.

  According to the second aspect of the present invention, by providing the capacitor portions on both surfaces of the insulating seat, a microphone unit having a variable directivity of a two-sided type with stable directivity characteristics and sensitivity can be formed.

  FIG. 1 is an explanatory view showing an example of a cross-sectional structure when a microphone unit according to the present invention is applied to a double-sided type, in which (a) shows the overall structure, and (b) shows the structure in (a). The enlarged view of a broken-line surrounding part is each shown. Moreover, FIG. 2 is an explanatory view showing the member configuration of the broken line encircled portion in FIG.

  According to these drawings, the microphone unit 11 includes a support ring 24 on which a diaphragm 23 is stretched, and a back electrode plate 25 disposed opposite to the diaphragm 23 with a predetermined gap therebetween. The entire capacitor portion 22 is formed as a double-sided opposing type in which the capacitor portion 22 is separately disposed on both sides of the insulating seat 42.

  In this case, the insulating seat 42 having a substantially cylindrical shape with a low seat height includes a large-diameter recessed portion 44 on one side surface and the other side surface, and a small-diameter recessed portion that is continuous in a stepped manner with the large-diameter recessed portion 44 being stepped. The portion 45 is formed separately, and the small-diameter recessed portions 45 and 45 communicate with each other through the communication hole 47.

  In addition, as is apparent from FIG. 2, the small-diameter recessed portions 45 are each provided with an annular projection 48 on the back bottom 46 side so as to be located slightly inside the inner peripheral surface 45 a, and the annular projection 48. Therefore, the back bottom 46 side is divided into an outer back bottom portion 46a and an inner back bottom portion 46b, and communicates with the communication hole 47 through the inner back bottom portion 46b.

  In addition, each inner back bottom 46b is covered with a sheet-like acoustic resistance material 52 having a circular shape. The acoustic resistance material 52 may have a substantially circular shape in addition to a perfect circle shape as long as it has a planar shape that can reliably cover the communication hole 47. . Moreover, as the acoustic resistance material 52, a plastic mesh from which a relatively stable acoustic resistance value can be obtained, a nylon mesh sheet (product number N-No. 420T) manufactured by NBC Kogyo Co., Ltd., or the like can be suitably used.

  In addition, a ring-shaped elastic material 53 made of silicone rubber or the like is disposed on the inner back bottom 46b side of the insulating seat 42 with an acoustic resistance material 52 interposed therebetween. The elastic material 53 is formed with a seat height higher than the depth of the small-diameter recessed portion 45 in a normal state. In addition, a ring-shaped support member 55 made of a metal material or the like is press-fitted into the small-diameter recessed portion 45 based on the positional relationship supported by the annular protrusion 48.

  Furthermore, in the insulating seat 42, the back electrode plate 25 is placed on the annular peripheral wall portion 49 that partitions each large-diameter recessed portion 44, so that the air chamber 32 is divided and formed separately. The capacitor portion 22 is formed by disposing the support ring 24 with the diaphragm 23 stretched on the exposed surface side.

  In addition, a male screw (not shown) is engraved on the outer peripheral surface of the annular peripheral wall portion 49 of the insulating seat 42, and a coupling ring 62 having a female screw (not shown) is screwed to the male screw so that the capacitor portion 22 is connected to each other. The entire double-sided microphone unit 11 provided separately is formed. In addition, the code | symbol 26 in a figure shows the electrode wire pulled out from each back electrode board 25. FIG.

  Next, the operation and effect of the present invention will be described based on the illustrated example. The elastic member 53 is supported by the inner back bottom 46b side of the insulating seat 42 with the acoustic resistance member 52 interposed therebetween. The top surface can be arranged in a state of slightly protruding from the small-diameter recessed portion 45.

  Further, the support member 55 is press-fitted and disposed in the small-diameter recessed portion 45 while pressing the protruding portion of the elastic material 53, so that the pressed portion of the elastic material 53 is placed on the inner circumference (communication hole 47) side as shown in FIG. ) As a bulging portion 53a.

  In addition, since the elastic member 53 is evenly pressed by the support member 55 having a larger diameter, the acoustic resistance member 52 that comes into contact with the elastic member 53 can be brought into close contact with the small-diameter deep bottom portion 46a.

  For this reason, a gap that allows air leakage is not formed between the acoustic resistance member 52 and the small-diameter back bottom portion 46a, so that the acoustic resistance value does not change due to air leakage. .

  On the other hand, the elastic material 53 that compresses and deforms protrudes as a bulging portion 53a on the side of the communication hole 47, but not only does not bulge at the contact portion with the acoustic resistance material 52, but the through hole depends on the amount of applied pressure. Since the opening dimension of the part 47 does not change, the acoustic resistance is not changed.

  Moreover, since the acoustic resistance material 52 itself can be disposed without using an adhesive, it is possible to prevent the occurrence of variations in the acoustic resistance value due to the penetration of the adhesive or the like.

Therefore, according to the present invention, it is possible to provide a variable directivity double-sided microphone unit 11 having stable performance such as directivity frequency characteristics and sensitivity.

  The above is the description of the present invention based on the illustrated example, and the specific configuration is not limited thereto. For example, the microphone unit 11 exemplifies a variable directivity condenser microphone unit formed in a double-sided type, but may be a unidirectional condenser microphone unit that does not have a double-sided type. The dynamic microphone unit may be used.

It is explanatory drawing which shows the end surface structure about an example of this invention formed in the double-sided opposing type | mold, (a) of them is a general view, (b) shows the enlarged view of the broken-line surrounding part of (a), respectively. . Explanatory drawing which decomposes | disassembles and shows each structural member based on the correspondence with FIG.1 (b). Explanatory drawing which shows the cross-sectional structure about an example of the microphone unit which pinched | interposed and arrange | positioned the conventional acoustic resistance material between the support members.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Microphone unit 22 Condenser part 23 Diaphragm 24 Support ring 25 Back electrode plate 26 Electrode wire 32 Air chamber 42 Insulation seat 44 Large diameter recessed part 45 Small diameter recessed part 45a Inner peripheral surface 46 Deep bottom 46a Outer deep bottom part 46b Inner deep bottom part 47 Communication Hole 48 Annular projection 49 Annular peripheral wall 52 Acoustic resistance material 53 Elastic material 53a Swelling portion 55 Support member 62 Connecting ring

Claims (2)

In the microphone unit comprising at least an acoustic resistance material for closing the communication hole provided in the insulating seat,
The insulating seat includes a large-diameter concave portion communicated with the communication hole on at least one side surface thereof, and a small-diameter concave portion continuous with the large-diameter concave portion with a step,
The small-diameter concave portion includes an outer back bottom portion and an inner back bottom portion whose inner bottom is partitioned by an annular protrusion,
In the inner back bottom, the acoustic resistance material is disposed, and an elastic material having a seat height higher than that of the annular protrusion is disposed in a normal state,
A microphone unit, wherein a support member supported via the annular protrusion is disposed in the small-diameter recess so as to freely press the elastic member.   Capacitor sections each consisting of a support ring with a diaphragm stretched and a back electrode plate facing each other with a predetermined gap between the diaphragm are disposed on both sides of the insulating seat. The microphone unit according to claim 1, wherein the microphone unit is a double-sided type.

Images