Microphone device

A microphone device includes a microphone unit that outputs an electrical signal upon receipt of a sound wave, a microphone case that supports the microphone unit in its inside with cushioning members formed of an elastic material (rubber material), and a microphone cable that supplies the electrical signal from the microphone unit to an output connector attached to the microphone case. A part of the microphone cable is attached in a state of meandering back and forth once or more between one surface and the other surface of the rear cushioning member formed in a flat manner. This configuration allows to suppress transmission of vibration through the microphone cable connected to the microphone unit and prevent generation of vibration noise due to free vibration of the microphone cable.

RELATED APPLICATIONS

The present application is based on, and claims priority from, Japanese Application No. JP2015-160636 filed Aug. 17, 2015, the disclosure of which is hereby incorporated by reference herein in its entirety.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a microphone device in which a microphone unit is attached inside microphone case with a cushioning member, and especially relates to a microphone device in which an arrangement of a microphone cable that leads out an electrical signal from the microphone unit is improved.

Description of the Related Art

In a case of a handheld microphone, a user directly holds the body of a microphone case. Therefore, applied vibration and acceleration are easily transmitted to the microphone unit in the microphone case. This generates a vibration noise called touch noise or handling noise.

Therefore, in this sort of microphone device, to prevent generation of the vibration noise, a configuration is employed in which the microphone unit is attached inside the microphone case with a cushioning member formed with a rubber material, and this microphone device is disclosed in patent publications, such as JP 2015-5942 A and JP 2008-177633 A.

The cushioning member that supports the microphone unit functions as a vibration isolator of the microphone unit and has a natural frequency of vibration, i.e. a resonant frequency. Therefore, when the cushioning member holding the microphone unit receives external vibration resonates, this causes to generate and output a large vibration noise output. Therefore, the resonant frequency needs to be set to a lower frequency band outside a sound collecting band of the microphone unit, or to a lower frequency band the noise at which seems to be inconspicuous even within the sound collecting band.

To achieve this, a high compliant material needs to be selected as the material of the cushioning member that functions as a vibration isolator, and accordingly the microphone unit can move in a large movable range in the microphone case.

Meanwhile, a microphone cable that leads an electrical signal from a microphone unit is connected between the microphone unit supported by the cushioning member and the microphone case that accommodates the microphone unit.

FIGS. 7 to 10exemplarily illustrate the above-described arrangement of the microphone cable in the conventional microphone device including a cushioning member.

Note that the conventional microphone device illustrated inFIGS. 7 to 10includes members that serve the same functions as an embodiment according to the present invention illustrated inFIGS. 1 to 6, described below, and the members are illustrated with the same reference signs. Therefore, detailed configurations of respective portions will be described below based onFIGS. 1 to 6.

A microphone cable45in the conventional microphone device is arranged in a space along a nearly central portion of a microphone case30, without forming slack as possible in a substantially linear manner, and connects between a microphone unit10and a connector47, as exemplarily illustrated inFIG. 7.

According to the configuration illustrated inFIG. 7, the microphone cable45is arranged in a state of floating in the air in a space portion between a microphone unit10and a connector47. Therefore, vibration received by a microphone case30is transmitted to the microphone unit10from the connector47through the microphone cable45, as schematically illustrated by the broken line. Accordingly, the vibration noise is generated.

To prevent the generation of the vibration noise through the microphone cable45, use of a thinner wire can be suggested as the microphone cable45.

However, when the microphone device is dropped and a large shock is applied to the microphone device, the microphone unit10instantly swings largely with being held by cushioning members41and42. Accordingly, a problem occurs that an unreasonable tension is applied to the microphone cable45and the microphone cable45may be disconnected, as illustrated inFIG. 8.

Therefore, when sufficient looseness is provided to the microphone cable45connected to between the microphone unit10and the connector47, as illustrated inFIG. 10, disconnection of the microphone cable45can be prevented if a large shock is applied to the microphone device, as described above. In this case, however, the microphone cable45freely vibrates, and the free vibration of the microphone cable45is transmitted to the microphone unit10, as illustrated inFIG. 9, and this may cause to generate the vibration noise.

That is, the bi-directional arrow illustrated inFIG. 9illustrates a state that the microphone cable45freely vibrates, and the broken line schematically illustrates a situation where the vibration of the microphone cable45is transmitted to the microphone unit10.

SUMMARY OF THE INVENTION

In the microphone device in which the microphone unit is supported in the microphone case with the cushioning member, the microphone cable connecting the microphone unit and the connector has problems of generating vibration noise due to respective causes, as described based onFIGS. 7 to 10. Further, the microphone device has a problem of disconnection of the microphone cable when receiving a shock.

Therefore, an objective of the present invention is to provide a microphone device that can effectively prevent transmission of external vibration to a microphone unit through a microphone cable and transmission of vibration due to own vibration of the microphone cable to the microphone unit, and can prevent disconnection of the microphone cable even when a large shock is applied to a microphone case.

A microphone device according to the present invention includes: a microphone unit configured to output an electrical signal upon receipt of a sound wave; a microphone case that supports the microphone unit in an inside through a cushioning member formed of an elastic material; and a microphone cable configured to supply the electrical signal from a side of the microphone unit to an output connector attached to the microphone case, wherein a part of the microphone cable is attached along the cushioning member.

In this case, in one preferable embodiment, the part of the microphone cable is attached in a state of meandering back and forth once or more between one surface and the other surface of the cushioning member formed in a flat manner.

More preferably, a configuration is employed in which the microphone unit is attached to a front end portion of a unit support portion, the microphone unit is swingably supported in the microphone case together with the unit support portion in an axial direction by a front cushioning member and a rear cushioning member in at least two places front and rear of the unit support portion in the axial direction, and a part of the microphone cable is attached to the rear cushioning member close to the output connector.

Meanwhile, the rear cushioning member is formed preferably in a ring-shaped manner, has a peripheral edge portion attached to the microphone case, and swingably in the axial direction supports the unit support portion in a central portion. And a part of the microphone cable is attached in a state of meandering back and force once or more between one surface and the other surface of the cushioning member formed in a flat manner, using a plurality of through holes formed along the ring-shaped surface of the rear cushioning member.

Then, preferably, a condenser microphone unit is used as the microphone unit, a circuit board including an audio output circuit of the condenser microphone unit is mounted immediately after the condenser microphone unit in the unit support portion, and the circuit board and the output connector are connected with the microphone canle.

In addition, a configuration is employed in which the microphone cable is attached in a bundle of a plurality of signal lines, in a state of meandering back and forth once or more between one surface and the other surface of the cushioning member.

According to the microphone device of the present invention, the configuration is employed in which a part of the microphone cable that supplies an electrical signal from the microphone unit to the output connector is attached along the cushioning member formed of an elastic material.

Therefore, the part of the microphone cable is always in contact with the cushioning member formed of a rubber material, for example, and thus direct transmission of vibration received at the microphone case to the microphone unit side through the microphone cable can be prevented. Accordingly, generation of vibration noise can be effectively suppressed.

Further, since apart of the microphone cable is in contact with the cushioning member, free vibration caused in the microphone cable itself is suppressed, and generation of vibration noise due to the free vibration of the microphone cable can be suppressed.

Further, the microphone cable along the cushioning member can be arranged with some looseness. Therefore, when a shock is applied to the microphone case, the microphone cable is similarly deformed following deformation of the cushioning member. Thus, application of a force such as providing excessive tension to the microphone cable can be effectively prevented.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A microphone device according to the present invention will be described based on an embodiment illustrated in the drawings.

FIGS. 1 and 3illustrate an example in which the present invention is applied to a condenser microphone by cross-sectional views. This condenser microphone includes, as a basic configuration, a microphone unit10, a unit support portion20, and a microphone case30.

In this embodiment, the microphone unit10is provided with a first element11and a second element12back to back.

Then, the microphone unit10is attached to a front end portion of the cylinder-shaped unit support portion20with a metal-made unit case13.

A dome-shaped cover21is attached to the cylinder-shaped unit support portion20, and a circuit board22including an audio output circuit of the microphone unit10is mounted in the unit support portion20right after the cover21.

The first element11in the microphone unit10configures a back electret condenser microphone unit in which a diaphragm faces a fixed electrode.

Meanwhile, the second element12does not configure a condenser microphone although including a fixed electrode and a diaphragm, and substantially functions as a high-pass filter (HPF) by cutting a low frequency range off of a sound wave entering from a rear acoustic terminal, and transmitting only a high frequency range to a back surface of the first element11. This HPF function especially improves low-range frequency characteristics of the condenser microphone.

Here, the acoustic terminal indicates a position of air that effectively provides a sound pressure to the microphone unit10. In other words, the acoustic terminal is a central position of the air moving at the same time with the diaphragm included in the microphone unit10. Since the microphone unit10is unidirectional, the acoustic terminals exist in front and back of the diaphragm, and the rear acoustic terminal is the acoustic terminal on the rear side of the diaphragm.

Then, a signal from the microphone unit10is led to the circuit board22through a relay rod23attached to a central portion of the dome-shaped cover21.

FIG. 2is an enlarged view of the microphone unit10, and hereinafter, specific description will be given. The first element11configures aback electret condenser microphone unit including a diaphragm11aand a fixed electrode11bfacing the diaphragm11a. Further, the fixed electrode11bis supported by a support member11chaving electric conductivity, and the diaphragm11ais supported by a diaphragm frame11d.

Similarly, the second element12also includes a diaphragm12a, a fixed electrode12b, a support member12c, and a diaphragm frame12d.

The two support members11cand12care fastened and fixed with a fastening member112having conductivity.

The fixed electrode11bof the first element11is electrically connected with the support member11c, the diaphragm12aand the fixed electrode12bof the second element12are electrically connected with the support member12c, and the support members11cand12care electrically connected with the fastening member112and the diaphragm frame12d. Accordingly, the condenser microphone unit by the first element11and the high-pass filter by the second element12are connected in series.

Further, a conductive screw113is attached to the diaphragm frame12d, and the relay rod23is electrically connected to the screw113.

The cylinder-shaped unit support portion20, having the microphone unit10mounted in the front end portion, is supported inside of the microphone case30in two places front and rear of the unit support portion20in an axial direction with a front cushioning member41and a rear cushioning member42.

The front cushioning member41and the rear cushioning member42are respectively made of rubber materials, and accordingly, the microphone unit10is swingably supported in the microphone case30in the axial direction together with the unit support portion20.

In the front cushioning member41, an outside of a thin flat ring-shaped portion41aforms a cylinder portion41b, and configures an attaching portion to the microphone case30. Further, an inside of the thin flat ring-shaped portion forms a short axial cylinder portion41c, and the cylinder portion41cencloses the unit support portion20.

Then, the outside cylinder portion41bof the front cushioning member41is sandwiched by an outer peripheral surface of a cylinder body43coaxially arranged in the microphone case30and an inner wall surface of the microphone case30, thereby being attached in the microphone case30.

Meanwhile, as illustrated inFIGS. 4 to 6, the rear cushioning member42includes a thin flat ring-shaped portion42a. An outer peripheral edge of the thin flat ring-shaped portion42ais folded back inward, and configures an attaching portion42bto the microphone case30. Further, a cylinder portion42cis integrally formed with an inside of the thin flat ring-shaped portion42a. This cylinder portion42csurrounds a hollow axial body24protruding in an axial direction and attached to a lower bottom portion of the unit support portion20. Accordingly, the rear cushioning member42supports the unit support portion20at the lower bottom portion.

Then, the attaching portion42bfolded back to an outer peripheral edge of the rear cushioning member42is locked with a lower end portion of the cylinder body43coaxially arranged in the microphone case30. This locking portion is attached by coming in contact with a step portion30a, having a slightly reduced inner diameter of the microphone case30, formed inside the microphone case30.

Note that six through holes42dare formed in the thin flat ring-shaped portion42aof the rear cushioning member42at regular intervals in a circumferential direction, as illustrated inFIG. 5. The through holes42dare formed to penetrate one surface (front surface) facing the inside of the microphone case30and the other surface (back surface) at an opposite side to the front surface. These through holes42dallow the thin flat ring-shaped portion42aof the rear cushioning member42to be flexibly configured, and allow a part of a microphone cable45to meander up and down (to sew a front surface and a back surface of the through holes42d) and locked.

An output connector47including a plurality of terminal pins47ais attached to a lower end portion of the microphone case30, and the microphone cable45is connected between the circuit board22arranged immediately after the microphone unit10and the output connector47. Note that although the microphone cable45is illustrated as a single cable in the drawings, the single cable consists of a bundle of a plurality of signal lines.

The microphone cable45is then hung down in a substantially linear manner in a central portion of the unit support portion20from the circuit board22, and is led out from the inside of the unit support portion20to the inside of the microphone case30through an opening20a(seeFIG. 4) formed in the lower bottom portion of the unit support portion20. Further, the microphone cable45pulled out from the unit support portion20is, as illustrated inFIGS. 4 to 6, attached to the rear cushioning member42using the through holes42dformed in the rear cushioning member42at regular intervals in the circumferential direction.

That is, the microphone cable45illustrated in the drawings is attached in a state of meandering back and forth twice and a half from the front surface side (upper surface side) to the back surface side (lower surface side) through the through holes42dof the rear cushioning member42. The microphone cable45pulled out to a lower surface side of the rear cushioning member42is then connected to the output connector47through an opening30cformed in an inner partition wall30bof the microphone case30in an axial direction.

The microphone cable45is fixed in the opening20aformed in the lower bottom portion of the unit support portion20with an adhesive20b, and is also fixed in the opening30cformed in the inner partition wall30bof the microphone case30with an adhesive30d. That is, the microphone cable45is fixed to the unit support portion20and the microphone case30with the adhesives20band30dat upper and lower portions of the rear cushioning member42.

The microphone cable45fixed with the adhesives20band30dthen meanders along an up and down direction of the rear cushioning member42, and is attached to the rear cushioning member42with some slacking.

Note that a ring member51to which a microphone front mesh50is attached is threaded into an upper end opening portion of the microphone case30, and accordingly, the microphone unit10attached to the front end portion of the unit support portion20is covered with the microphone front mesh50.

According to the microphone device having the above-described configuration, the microphone unit10is attached to the microphone case30together with the unit support portion20through the front cushioning member41and the rear cushioning member42.

Therefore, even if a shock is applied to the microphone case30, transmission of the shock to the microphone unit10is effectively reduced, as illustrated inFIGS. 3 to 6, and generation of vibration noise can be suppressed.

In addition, a part of the microphone cable45that supplies the electrical signal from the microphone unit10side to the output connector47side is attached along the rear cushioning member42. Therefore, transmission of vibration to the microphone unit10side through the microphone cable45can be effectively prevented. Further, the rear cushioning member42can suppress free vibration of the microphone cable45itself. Therefore, suppression effects of the vibration noise can be further exhibited.

Note that the above embodiment has been described using the condenser microphone as an example. However, the present invention can be applied to dynamic microphones, for example. Especially, the dynamic microphones are susceptible to inertial force due to an increase in a weight of a voice coil, and as measurements of that, it is desirable to use a more compliant cushioning member.

According to the present invention, the microphone cable45can be similarly deformed following a relatively large deformation operation of the cushioning member. Therefore, the above-described functions and effects such as avoidance of application of stress to the microphone cable can be obtained.