JP4647416B2 - Condenser microphone - Google Patents

Description

  The present invention relates to a condenser microphone in which electromagnetic waves can be prevented from entering a case of a microphone unit from a shield wire in a dedicated microphone cord and noise generated from the electromagnetic waves can be effectively prevented.

  Since the condenser microphone has a high impedance of the microphone unit, a high input impedance is usually converted into a low output impedance by interposing an impedance converter composed of an FET or the like.

  On the other hand, in the case of a minute type condenser microphone used for a conference microphone, a choir microphone, a tiepin type microphone, etc., it is necessary to make the presence inconspicuous at the time of use. For this reason, an impedance converter is built in the microphone unit side, and a dedicated microphone cord drawn out from the microphone unit side is connected to the circuit storage unit side where the low cut circuit and output circuit are stored and placed elsewhere It is used as it is.

  In this case, the dedicated microphone cord has a two-core shield structure, that is, a power supply line for supplying power to the microphone unit side, a signal line for sending an audio signal output from the impedance converter to the circuit housing side, and these power supplies A wire having a shield wire that electrostatically shields the wire and the signal wire and grounds the wire is used.

In addition, the connection of the dedicated microphone cord to the microphone unit side is formed in a state where the power supply line and the signal line in the dedicated microphone cord are electrically independent on the printed circuit board as disclosed in, for example, Patent Document 1 below. This is done by connecting each of the connecting lands separately to each other and connecting the shield wire side to a shielding land formed on the printed circuit board.
Utility Model Registration No. 3027420

  FIG. 3 is a longitudinal cross-sectional view showing an enlarged main part of a conventional unidirectional microphone unit as an example of a connection method of a dedicated microphone cord to the condenser microphone side, which has been conventionally performed including Patent Document 1. is there. According to the figure, a condenser microphone 1 includes a microphone unit 2 in which necessary members such as a printed circuit board 3 and a capacitor portion 5 on which an impedance converter 4 made of an FET is mounted are accommodated in an upper case portion 6a; A metal case 6 comprising a lower case portion 6b from which a dedicated microphone cord 7 is pulled out in combination with the microphone unit 2 while supporting the substrate 3 is provided.

  In this case, the dedicated microphone cord 7 has a power line 7a that supplies power to the microphone unit 2 side to one connection land of the printed circuit board 3, and an audio signal output from the impedance converter 4 to the circuit housing unit (not shown). The signal line 7b to be connected is drawn out to the other connection land of the printed circuit board 3, and the shield line 7c is drawn out to the grounding land of the printed circuit board 3 under the respective soldered conditions.

  In addition, the dedicated microphone cord 7 drawn out from the microphone unit 2 side is held by the cord holding member 8 disposed in the lower case portion 7b and fixed to the lower case portion 7b and the cord bush. 9 is sent out to a circuit housing portion (not shown).

  However, in the case of the connection structure of the dedicated microphone cord shown in FIG. 3, if a strong electromagnetic wave emitted from a mobile phone or the like is applied to the shielded wire 7 c side of the dedicated microphone cord 7, the electromagnetic wave is generated in the upper case portion 6 a of the microphone unit 2. The high frequency current derived from the intrusion enters, and there is a disadvantage that noise is generated.

  The present invention has been made in view of the above-described problems of the prior art, and a condenser microphone in which electromagnetic waves are prevented from entering into a microphone unit from a shield wire in a dedicated microphone cord, and generation of noise derived from the electromagnetic waves can be effectively prevented. The purpose is to provide.

The present invention has been made to achieve the above object, and a condenser microphone unit in which a necessary member including a printed circuit board on which an impedance converter or the like is mounted and a capacitor portion is housed in a metal case, and the capacitor microphone at least Bei example a dedicated microphone cord drawn electrically connected to the unit side, wherein the metal case are combined to detachably screwed a respective female thread male screw connecting interposing material is provided which is interposed An upper case portion and a lower case portion are formed, and in the lower case portion, a cylindrical body portion that comes into contact with and communicates with the lower case portion side and / or the grounding land side provided on the printed circuit board, and the cylinder with an electrically conductive flexible holding member which is continuously provided on the lower side of the body portion comprising a reduced diameter portion comprising a slope portion on its outer peripheral surface is interposed, When the upper case part is tightened and screwed to the connecting intermediary material, the reduced diameter is caused by the bending deformation that occurs when the inclined surface comes into pressure contact with the guide inclined surface that the lower case part has on the inner peripheral surface on the lower end side thereof. part forcibly diameter of at Rukoto pulled out difficult to embrace shield layer formed on an outer peripheral surface of the one end side of the dedicated microphone cord folded back shield wires to the sheath side, the shield layer The most important feature is that a conductive line is formed from the flexible clamp to the grounding land of the printed circuit board .

In this case , it is desirable that the diameter-reduced portion is provided with a sawtooth portion for preventing the sliding on the contact surface of the dedicated microphone cord with the one end portion. Furthermore, it is preferable that the flexible holding body is formed by using a synthetic resin material as a base material and providing a conductive layer on the exposed surface of the base material.

According to the present invention, the dedicated microphone cord is used in a state in which the exposed shield wire is folded back to the sheath side and a shield layer is formed on the outer peripheral surface of the one end side, and the shield layer is forcibly reduced in diameter. reduced diameter portion of the flexible holding member having conductivity that is can be pulled out difficult Idaku lifting through.

Moreover, by was standing disposed through the flexible holding member, can form a conductive line from the shield layer via the flexible holding member reaches the printed circuit board side of the ground land obtain the required shielding effect.

Therefore, even when a mobile phone is used in the vicinity of a condenser microphone, it is possible to effectively prevent electromagnetic waves generated from the mobile phone from entering inside the metal case. By disassembling the upper case portion and the lower case portion, it is possible to easily perform repair in the event of a failure.

  FIG. 1 is an enlarged longitudinal sectional view showing an essential part of an example when the present invention is applied to a unidirectional microphone unit. According to the figure, the condenser microphone 11 includes a condenser microphone unit 12 in which necessary members including a printed circuit board 13 on which an impedance converter 14 and the like are mounted and a capacitor portion 15 are housed in a metal case 22, and the condenser microphone. The unit 12 is provided with at least a dedicated microphone cord 62 that is drawn out by electrically connecting one end 63 thereof.

  In this case, the metal case 22 is formed of an upper case portion 23 and a lower case portion 25 that are detachably combined with the opening surfaces 24 and 26 facing each other, and a connecting intermediary material 30 interposed between them. Can be connected together. In this case, the connecting intermediary material 30 includes a male screw that is screwed with the female screw of the upper case portion 23 and a male screw that is screwed with the female screw of the lower case portion 25. First, an adhesive is attached to the female screw portion of the lower case portion 25. In addition, by fixing the connecting intermediary material 30 side by screwing, the upper case portion 23 side and the connecting intermediary material 30 side are screwed together, The case portion 23 and the lower case portion 25 are integrally connected.

  In addition, the condenser microphone unit 12 mainly stores necessary members such as the capacitor portion 15 including the diaphragm 16 and the back electrode plate 17 and the printed circuit board 13 on which the impedance converter 14 and the like are mounted in the upper case portion 23. It is formed with.

  In addition, the lower case portion 25 is provided with a receiving groove portion 27 that supports the printed circuit board 13 so as to support the printed circuit board 13 on the upper end surface located on the opening surface 26 side, and leads out while protecting the dedicated microphone cord 62. The base end surface is provided with a lead-out hole 28 having a stepped portion 28a for locking the cord bush 32 through its flange 33.

  Further, the lower case portion 25 includes a guide slope portion 29 formed on the inner peripheral surface 25a located slightly above the step portion 28a so as to be lowered forward toward the lead-out hole 28.

In addition, the inside of the lower case portion 25 is forcibly reduced in diameter when combined with the upper case portion 23 so as to be freely held by the one end portion 63 side of the dedicated microphone cord 62. A flexible sandwiching body 42 is interposed. The flexible clamping body 42 is brought into contact with the lower case portion 25 to be conducted, or the upper end 42a side is brought into contact with a grounding land (not shown) provided on the printed circuit board 13 as shown in FIG. And a reduced diameter portion 44 having a slope portion 45 that is located on the lower end side of the cylindrical portion 43 and that is inclined forward inwardly on the outer peripheral surface 43a thereof. And is formed.

  2A and 2B are explanatory views specifically showing an example of the flexible sandwiching body 42, in which (a) is a plan view, (b) is a side view, (c) is a front view, and (d). These show the longitudinal cross-sectional view in the AA arrow direction in (a), respectively.

  According to the figure, when the flexible clamping body 42 is disposed in the lower case portion 25, the inclined surface portion 45 is positioned on the upper inclined surface of the guide inclined surface portion 29 of the lower case portion 25, and the upper case portion 23 is When pressed by screwing, the inclined portion 35 is deformed while being pushed down toward the lower inclined surface of the guide inclined portion 29 of the lower case portion 25, that is, the reduced diameter portion 44 is reduced in diameter, and the dedicated microphone. The cord 62 is formed with an outer dimension that allows the one end 63 side of the cord 62 to be held under a biting condition.

  In this case, the flexible sandwiching body 42 has an appropriate width and length, and is parallel to the cylinder portion 43 from the proximal end side toward the cylinder direction and spaced apart by 120 degrees in the circumferential direction. Two notches 46 and 47, and each of the notches 46 and 47 and a wide slit portion 48 formed over the entire length in the cylinder direction with an interval of 120 degrees in the circumferential direction. These cutout portions 46 and 47 and the wide slit portion 48 form a reduced diameter portion 44 on the skirt side.

  In addition, the flexible clamping body 42 is formed in a direction perpendicular to the cylinder direction so as to generate a frictional force that prevents sliding on the inner peripheral surface 44 a that contacts the one end 63 side of the dedicated microphone cord 62 around the reduced diameter portion 44. One or more ridges, preferably a plurality of serrated portions 49 are provided.

Further, the flexible sandwiching body 42 formed with such a structure has a conductive layer 50 formed by using an appropriate insulating synthetic resin material as a base material and performing gold plating on the exposed surface of the base material. Is formed.

  In addition, the dedicated microphone cord 62 folds the exposed shield wire 65 to the sheath 64 side so as to protrude from the outer peripheral surface 65 on the one end 63 side and the end surface 64a side on the sheath 64 side. One core wire 68 used as a power supply line for supplying power to the condenser microphone unit 12 side, and a signal line for sending an audio signal output from the impedance converter 14 to a circuit housing unit side (not shown) located elsewhere. And the other core wire 69 used.

  In this case, the core wires 68 and 69 located on the one end 63 side of the dedicated microphone cord 62 are electrically connected to each predetermined position of the printed circuit board 14 by soldering.

  Next, the operation of the example of the present invention having the above-described configuration will be described with reference to FIG. 1. First, the dedicated microphone cord 62 has the core wires 68 and 69 projected from the end face 64a on the sheath 64 side. Soldering is individually performed at each predetermined position on the printed circuit board 14.

  Further, the dedicated microphone cord 62 has a shield layer 67 formed on the outer peripheral surface 65 on the one end portion 63 side by folding the exposed shield wire 65 to the sheath 64 side. The arrangement is positioned within the reduced diameter portion 45 of the flexible sandwiching body 42, and the cord bush 32 that is locked to the lead-out hole 28 of the lower case portion 25 is inserted through the cord unit 32 and pulled out from the microphone unit 12 side. .

  The upper case portion 23 and the lower case portion 25 form the microphone unit 12 including the metal case 22 that is integrally connected with the connection interposition body 30 interposed therebetween under such an arrangement relationship. become.

  In addition, when the metal case 22 is formed by the upper case portion 23 and the lower case portion 25, the flexible sandwiching body 42 disposed in the lower case portion 25 has a slope portion 45 whose guide slope is the lower case portion 25. The reduced diameter portion 44 is forcibly reduced in diameter by being bent and deformed while being pushed down toward the lower inclined surface of the portion 29.

  When the reduced diameter portion 44 of the flexible clamping body 42 is reduced in diameter, the reduced diameter portion 44 is provided on the inner peripheral surface of the shield layer 67 formed on the outer peripheral surface 65 on the one end portion 63 side of the dedicated microphone cord 62. Under the state of being bitten by the serrated portion 49, it is held with difficulty in removal.

  In addition, since the conductive layer 50 is formed on the outer surface of the flexible sandwiching body 42, a conductive line extending from the shield layer 67 → the flexible sandwiching body 42 → the grounding land of the printed circuit board 13 is formed to be a predetermined one. The shield effect can be obtained.

  Therefore, even when the mobile phone is used in the vicinity of the condenser microphone 11, it is possible to effectively prevent electromagnetic waves generated from the mobile phone from entering the inside of the metal case 22.

  For this reason, according to the present invention, it is possible to prevent the generation of noise by preventing the high-frequency current derived from the electromagnetic wave generated in the vicinity of the condenser microphone 11 from entering.

  Further, since the metal case 22 can be disassembled into the upper case portion 23 and the lower case portion 25 and the forced diameter reducing action on the diameter reducing portion 44 of the flexible sandwiching body 42 can be released, repair in the event of a failure. Can be easily performed.

  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 present invention can be applied not only to unidirectionality but also to a microphone unit having an omnidirectional structure. Further, the flexible sandwiching body 42 can be formed entirely using a conductive synthetic resin material.

Further, the reduced diameter portion 44 in the flexible sandwiching body 42 can be formed with only an appropriate number of notches or only one wide slit portion as long as the forced reduction is possible. . Further, the flexible sandwiching body 42 is formed by providing an appropriate sliding prevention structure different from the sawtooth portion 49 on the inner peripheral surface 44a of the reduced diameter portion 44, or in some cases without providing a sliding prevention structure. It can also be formed .

The longitudinal cross-sectional view which expands and shows the principal part about an example at the time of applying this invention to a unidirectional microphone unit. It is explanatory drawing which shows an example of a flexible clamping body concretely, of which (a) is a top view, (b) is a side view, (c) is a front view, (d) is in (a). The longitudinal cross-sectional view in an AA arrow direction is shown, respectively. The longitudinal cross-sectional view which expands the principal part for the example of the unidirectional microphone unit for the conventional connection method of the exclusive microphone cord with respect to the condenser microphone side as an example.

DESCRIPTION OF SYMBOLS 11 Condenser microphone 12 Condenser microphone unit 13 Printed circuit board 14 Impedance converter 15 Capacitor part 16 Diaphragm 17 Back electrode plate 22 Metal case 23 Upper case part 24 Opening surface 25 Lower case part 25a Inner peripheral surface 26 Opening surface 27 Receiving groove part 28 Derivation hole 28a Stepped portion 29 Guide slope portion 30 Connection interposing body 32 Code bush 33 Hook portion 42 Flexible clamping body 43 Cylindrical body portion 43a Outer peripheral surface 44 Reduced diameter portion 44a Inner peripheral surface 45 Slope portion 46, 47 Notch portion 48 Wide slit portion 49 Sawtooth portion 50 Conductive layer 62 Dedicated microphone cord 63 One end portion 64 Sheath 64a End surface 65 Outer surface 66 Shield wire 67 Shield layer 68, 69 Core wire

Claims (3)

A capacitor microphone unit in which necessary members including a printed circuit board on which an impedance converter and the like are mounted and a capacitor unit are housed in a metal case, and a dedicated microphone cord that is electrically connected to the capacitor microphone unit side and drawn out at least Bei example,
The metal case is formed of an upper case portion and a lower case portion that are detachably combined by screwing each female screw into a male screw included in an interposingly arranged connecting material ,
In the lower case portion, a cylindrical body portion that is in contact with the lower case portion side and / or the grounding land side provided on the printed circuit board, and is connected to the lower end side of the cylindrical body portion, and the outer periphery thereof is connected. While interposing and arranging a conductive flexible clamping body composed of a reduced diameter portion having a slope portion on the surface ,
When the upper case portion is tightened and screwed to the connecting intermediary material, the reduced diameter is caused by the bending deformation that occurs when the inclined portion is brought into pressure contact with the guide inclined portion that the lower case portion has on the inner peripheral surface on the lower end side. part forcibly diameter of at Rukoto pulled out difficult to embrace shield layer formed on an outer peripheral surface of the one end side of the dedicated microphone cord folded back shield wires to the sheath side,
A capacitor microphone, wherein a conductive line extending from the shield layer to the grounding land of the printed circuit board through the flexible sandwiching body is formed . 2. The condenser microphone according to claim 1, wherein the reduced diameter portion is provided with a sawtooth portion for preventing sliding on a contact surface of the dedicated microphone cord with the one end side . It said flexible clamping bearing member is a synthetic resin material as a base material, the condenser microphone according to claim 1 or 2 provided with the conductive layer on the exposed surface of the substrate.

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