JP2009200869A - Narrow directional capacitor microphone - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a narrow directional capacitor microphone that suppresses noise generation due to entry of humming noise and a high-frequency current, and cavity resonance, make wind noise small, and also eliminate eccentricity of an internal unit while making a sound tube small in radial size. <P>SOLUTION: The narrow directional capacitor microphone includes the sound tube 12 having a sound resistance hole 16 covered with a sound resistance material 17, the internal unit 22 exhibiting a capacitor microphone function, and a conductive interposing material 32 made of a mesh type elastic metal material covering the internal unit. The sound tube 12 includes a step portion 15 on an inner peripheral surface 14 on the side of a base end portion 13, and the internal unit 22 is sent together with the conductive interposing material 32 up to the position where it abuts against the step portion 15 to be united with the sound tube 12. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a narrow-directional condenser microphone that can suppress the generation of noise by making it difficult to enter hum noise and high-frequency current while realizing shortening in the radial direction.

In a narrow directivity condenser microphone with a small diameter, the outer casing is formed of an acoustic tube. Moreover, the acoustic resistance material that closes the acoustic resistance hole provided on the peripheral side surface of the acoustic tube is attached to the inner surface side of the acoustic tube, for example, as disclosed in Patent Document 1 below, so as not to impair the appearance. Will be.
Japanese Utility Model Publication No. 5-34794

  In this case, since the outer diameter of the microphone unit having the front acoustic terminal and the rear acoustic terminal is smaller than the inner diameter in the acoustic tube, a gap is secured between the acoustic unit and the acoustic tube when the acoustic unit is housed in the acoustic tube. However, when the both are fixed using an adhesive, the gap is closed.

  Also, when the microphone unit is fixed to the acoustic tube with an adhesive, the electrical connection between the microphone unit and the acoustic tube becomes unstable, and sufficient shielding cannot be obtained, causing hum noise and high frequency current. It becomes easy to enter and generate noise.

For this reason, the applicant of the present application uses the narrow directivity condenser microphone disclosed in Patent Document 2 below in order to suppress the generation of noise by making it difficult to enter hum noise or high-frequency current in such a case. is suggesting.
JP 2006-81075 A

  FIG. 5 is a side view of an appearance example of a narrow directivity condenser microphone disclosed in Patent Document 2, and FIG. 6 is a vertical end view of the acoustic tube and the microphone unit separated from each other. 7 is a vertical end view of FIG. 5, and FIG. 8 is an enlarged view of the circular surrounding portion in FIG.

  According to these figures, the narrow directivity condenser microphone has an acoustic tube 1 having an acoustic resistance hole 2 whose inner side surface is covered with an acoustic resistance material 3 on the peripheral side surface, and a built-in unit component 8 in a unit case 7. And a microphone unit 6 which is housed and formed.

  Further, the acoustic tube 1 is thinned so that the inner diameter of the inner peripheral surface 5 of the part located on the base end part 4 side can be larger than the inner diameters of the other parts, so that the step part 5a is formed at the boundary part. Is formed.

  Then, as shown in FIG. 6, the microphone unit 6 is disposed on the step portion 5a of the acoustic tube 1 together with the conductive interposing material 9 having a substantially U-shaped cross-section disposed so as to cover the front acoustic terminal 6a side. It is fed to the position where it abuts and is integrated with the acoustic tube 1 side as shown in FIG.

  A narrow directivity condenser microphone called a line microphone formed in this manner has an electrical conduction state between the acoustic tube 1 and the microphone unit 6 by interposing a conductive interposing material 9 between them. Since it can be ensured, it is difficult to enter hum noise and high-frequency current, and noise generation can be suppressed.

  By the way, there is a demand for a narrow directivity condenser microphone called a line microphone in order to further reduce the radial dimension in order to realize a narrow directivity with a small diameter.

  However, in the case of using the narrow directivity condenser microphone disclosed in Patent Document 2 (see FIGS. 5 to 8), the conductive interposing material 9 is interposed between the acoustic tube 1 and the microphone unit 6. Therefore, the dimension in the radial direction is increased by the amount of the interposed conductive interposing material 9, and there is a problem that the above request cannot be met.

  In view of the above-mentioned problems of the prior art, the present invention is capable of suppressing noise generation by eliminating hum noise and high-frequency current entry while reducing the radial dimension, and suppressing occurrence of cavity resonance. An object is to provide a narrow directional condenser microphone that can reduce wind noise and eliminate the eccentricity of the built-in unit.

  The present invention has been made in order to achieve the above object, and includes an acoustic tube made of a conductive metal material having an appropriate length and provided with an acoustic resistance hole whose inner side is covered with an acoustic resistance material, A built-in unit that includes a front acoustic terminal and a rear acoustic terminal to exert a condenser microphone function, and a conductive interposer made of a mesh-like elastic metal material having a substantially U-shaped cross section that covers the built-in unit from the front acoustic terminal side And the acoustic tube has a stepped portion formed by making its inner diameter smaller than the outer diameter of the built-in unit covered with the conductive intercalation material on the inner peripheral surface on the base end side. The built-in unit is fed back to the position where it comes into contact with the step portion from the proximal end opening of the acoustic tube together with the conductive intervening material, and is integrated with the acoustic tube. To do.

  The conductive interposing material in the present invention is formed so as to exhibit a bottomed cylindrical shape with a taper whose diameter is slightly reduced toward the side facing the front acoustic terminal. preferable.

  According to the first aspect of the present invention, the built-in unit covered with the conductive interposing material is fed into the base end portion of the acoustic tube from the front acoustic terminal side and integrated with the acoustic tube side. Since the built-in unit can be arranged without being accommodated in the unit case, the dimension in the radial direction can be shortened as much as the unit case is unnecessary.

  In addition, since a conductive intervening material is interposed between the acoustic tube and the built-in unit, the electrical continuity between the acoustic tube and the built-in unit can be ensured, and hum noise can be ensured. In addition, the generation of noise can be suppressed by making it difficult for high-frequency current to enter.

  In addition, since the conductive interstitial material is formed using a mesh-like elastic metal material having air permeability, a substantial ventilation portion is formed between the acoustic tube and the built-in unit while suppressing the occurrence of cavity resonance. Can be ensured, and the generation of wind noise can be reduced by balancing the pressure difference between the front acoustic terminal and the rear acoustic terminal.

  Furthermore, the built-in unit can be arranged without being eccentric while being in close elastic contact with the acoustic tube side through the conductive interposing material without interposing a gap.

  Moreover, according to the invention which concerns on Claim 2, the electroconductive intervention material exhibits the bottomed cylindrical shape to which the taper by which the surrounding wall part is diameter-reduced a little toward the facing side with a front part acoustic terminal was attached. Since it is formed, the built-in unit and the acoustic tube are more securely electrically connected by placing them so as to be pressed into the stepped portion located in the base end portion of the acoustic tube. The position can be fixed with.

  FIG. 1 is a side view of an external appearance example of the present invention, FIG. 2 is an explanatory diagram in a state where an acoustic tube, a built-in unit, and a conductive intercalation material are separated from each other, and FIG. FIG. 4 is a longitudinal sectional view, and FIG. 4 is an enlarged view of the circular encircling region in FIG.

  According to these figures, the narrow directivity condenser microphone 11 has an appropriate length having an acoustic resistance hole 16 covered with an acoustic resistance material 17 on its peripheral side surface 12a, as is apparent from FIGS. A built-in unit 22 including a sound tube 12 made of a conductive metal material, a front sound terminal 23, and a rear sound terminal 24, each of which is composed of required parts for exhibiting a condenser microphone function, and the built-in unit 22 And a conductive interposing material 32 made of a mesh-like elastic metal material having a substantially U-shaped cross-section covering the front acoustic terminal 23 side.

  Among these, the acoustic tube 11 having a substantially cylindrical shape is formed using a conductive metal tube material such as an aluminum tube material having an appropriate inner diameter determined by the relationship with the outer diameter on the side of the built-in unit 22 to be accommodated.

  Moreover, the acoustic tube 12 is formed by making the inner diameter smaller than the outer diameter of the built-in unit 22 covered with the conductive interposing material 32, that is, by making the inner wall thickness thinner than other parts. A step portion 15 is provided on the inner peripheral surface 14 on the base end portion 13 side. Reference numeral 19 in the figure denotes a female screw portion for screwing and connecting to a grip side (not shown).

  The built-in unit 22 formed in a bare shape without being accommodated in the unit case is formed by combining necessary parts necessary for exhibiting the condenser microphone function in a predetermined procedure. A front acoustic terminal 23 is disposed on the front end side, and a rear acoustic terminal 24 is disposed on the rear end side.

  On the other hand, the conductive intercalation material 32 is formed by drawing a mesh-like elastic metal material, for example, a stainless mesh of # 100 having a diameter of 0.1 mm, and a surface where the front acoustic terminal 23 is located in the built-in unit 22 and its peripheral surface. A shape capable of densely covering a portion (excluding the rear acoustic terminal 24 side) is provided and formed.

  Specifically, the conductive interposing material 32 is tapered such that the peripheral wall 34 is slightly reduced in diameter toward the bottom 33 facing the front acoustic terminal 23 as shown in the example of the drawing. For example, it is formed by drawing or the like so as to exhibit a bottomed cylindrical shape. In addition, the electroconductive intervention material 32 may form the whole surrounding wall part 34 with the same diameter, without attaching a taper like the example of illustration.

  In this case, the conductive intercalation material 32 has a dimension such that the inner diameter on the bottom 33 side thereof substantially coincides with the outer diameter of the surface on which the front acoustic terminal 23 of the built-in unit 22 is located. Further, the step portion 15 provided on the inner peripheral surface 14 on the base end portion 13 side of the acoustic tube 12 has an inner diameter enough to allow the conductive interposing material 32 to abut / hang on the bottom portion 33. It is granted and formed.

  The acoustic tube 12, the built-in unit 22, and the conductive interposing material 32 having the above-described configuration are assembled as follows, for example. That is, as shown in FIG. 2, the front acoustic terminal 23 side of the built-in unit 12 faces the opening 35 side of the conductive intervention material 32, and the front acoustic terminal 23 is connected to the conductive intervention material. 32 to the contact position with the bottom 33 of 32.

  After combining the built-in unit 22 and the conductive interposing material 32 in this way, the base end portion with the bottom 33 of the conductive interposing material 32 facing the base end opening 18 of the acoustic tube 12 is provided. 14 is also sent together with the built-in unit 22.

  At this time, the conductive interposing material 32 covering the built-in unit 22 is connected to the step portion 15 provided on the inner peripheral surface 14 on the base end portion 13 side of the acoustic tube 12 via the bottom portion 33 on the front acoustic terminal 23 side. At the same time, it is stably contacted and supported.

  Moreover, between the inner peripheral surface 14 on the base end 13 side of the acoustic tube 12 and the outer peripheral side including the front acoustic terminal 23 of the built-in unit 22, a conductive interposing material 32 made of a mesh-like elastic metal material is provided. It will be densely interposed with air permeability. In addition, when using a conductive intercalation material 32 with a taper, it is between the inner peripheral surface 14 on the base end portion 13 side of the acoustic tube 12 and the built-in unit 22 in a more closely contacted state. Can intervene.

  Therefore, the built-in unit 22 can be arranged in the base end portion 13 of the acoustic tube 12 without being decentered, and the electrical conduction state with the acoustic tube 12 can be ensured. In addition, the generation of noise can be suppressed by making it difficult for high-frequency current to enter.

  Furthermore, since the conductive intercalation material 32 is formed using a mesh-like elastic metal material having air permeability, it is substantially between the acoustic tube 12 and the built-in unit 22 while suppressing the occurrence of cavity resonance. Thus, it is possible to secure a proper ventilation portion, and balance the pressure difference between the front acoustic terminal 23 and the rear acoustic terminal 24 to reduce the generation of wind noise.

  Moreover, according to the present invention, the built-in unit 22 covered with the conductive interposing material 32 is fed into the proximal end portion 13 of the acoustic tube 12 from the front acoustic terminal 23 side with the front acoustic terminal 23 side as a head. By integrating with the acoustic tube 12 side, the built-in unit 22 can be arranged without being accommodated in the unit case, so that the size in the radial direction can be shortened by the amount that the unit case is unnecessary. Can do. That is, the acoustic tube 12 can be used with a smaller diameter.

The side view which shows the example of an external appearance structure of this invention. Explanatory drawing which shows the end surface structure in the state which isolate | separated the acoustic tube, the built-in unit, and the electroconductive intervention material mutually. The longitudinal cross-sectional view of FIG. FIG. 2 is a vertical end view of FIG. 1. FIG. 4 is an enlarged detail view of a circular go region in FIG. 3. The side view which shows the example of an external appearance structure of the conventional narrow directivity | capacitance microphone. FIG. 6 is an explanatory diagram illustrating an end surface structure in a state where the acoustic tube, the microphone unit, and the conductive interposing material are separated from each other in the example illustrated in FIG. 5. FIG. 6 is a vertical end view of FIG. 5. FIG. 8 is an enlarged detail view of a circular go region in FIG. 7.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Narrow directivity condenser microphone 12 Acoustic tube 12a Peripheral side surface 13 Base end part 14 Inner peripheral surface 15 Step part 16 Acoustic resistance hole 17 Acoustic resistance material 18 Base end opening 19 Female screw part 22 Built-in unit 23 Front acoustic terminal 24 Rear acoustic terminal 32 Conductive intervention material 33 Bottom 34 Peripheral wall 35 Opening

Claims (2)

Capacitor microphone function with an acoustic tube made of conductive metal material of appropriate length with an acoustic resistance hole covered on the inner side with an acoustic resistance material, and a front acoustic terminal and a rear acoustic terminal A built-in unit, and a conductive interstitial material made of a mesh-like elastic metal material having a substantially U-shaped cross section covering the built-in unit from the front acoustic terminal side,
The acoustic tube is provided with a stepped portion formed on the inner peripheral surface thereof on the base end side, which is formed by making the inner diameter smaller than the outer diameter of the built-in unit covered with the conductive intervention material,
Narrow directional condenser microphone, wherein the built-in unit is fed together with the conductive intercalation material from the proximal end opening of the acoustic tube to a position where it comes into contact with the stepped portion and integrated with the acoustic tube. .   The conductive interposition material is formed so as to exhibit a bottomed cylindrical shape with a taper in which the peripheral wall portion is slightly reduced in diameter toward the side facing the front acoustic terminal. The described narrow directional condenser microphone.

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