JP5085146B2 - Ribbon microphone unit and ribbon microphone - Google Patents

Description

  The present invention relates to a ribbon microphone unit using a movable diaphragm (hereinafter referred to as a “ribbon-shaped diaphragm”) formed in a ribbon shape, and a ribbon microphone including the ribbon microphone unit. TECHNICAL FIELD OF THE INVENTION

  One type of magnetoelectric microphone that collects sound by using electromotive force generated by vibration of a diaphragm is a ribbon microphone that uses a ribbon diaphragm. This ribbon microphone has been avoided for a long time because of its low sensitivity. Has attracted attention in the field.

Such a ribbon microphone includes a ribbon microphone unit as shown in FIGS.
FIG. 4 is a front view showing an example of a conventional ribbon microphone unit. FIG. 5 is a longitudinal sectional view taken along the line II-II indicated by a one-dot chain line in FIG.
4 and 5, the ribbon microphone unit 101 includes a support 102, a pair of magnets 104 and 104 that form a magnetic field attached to the support 102, and a ribbon disposed in the magnetic field of these magnets 104. The main structure is to include the shape diaphragm 103.

Further, in the ribbon microphone unit, the ribbon diaphragm is loosely stretched while an appropriate tension is applied by pressing one end side and the other end side in the length direction. For this reason, a ribbon microphone equipped with such a ribbon microphone unit has a light vibration system and is easy to move, and is vulnerable to noise such as human breath and external mechanical vibration. Can be picked up, that is, it has the advantage of having a wide frequency band.
In the ribbon microphone, when the ribbon diaphragm receives a sound wave and vibrates in a magnetic field, electricity flows through the ribbon diaphragm and the sound wave is converted into an electric signal.

  Conventionally, a ribbon-shaped diaphragm such as a thin conductor with a thickness of a few microns, which has been cut into an elongated shape, is used. Specifically, aluminum foil is often used as a material for the ribbon diaphragm. This aluminum is suitable as a ribbon-type diaphragm for a ribbon microphone because of its good conductivity and low specific gravity compared to other metal materials.

  Further, since the bidirectional ribbon microphone is mass-controlled, the low-frequency reproduction limit can be made lower as the resonance frequency of the diaphragm is lower. However, if the resonance frequency is too low, problems such as contact with the magnetic poles due to wind and vibration are generated. When a strong impact or wind pressure is applied to the ribbon diaphragm, the ribbon diaphragm is plastically deformed (stretched), resulting in a failure.

The ribbon diaphragm needs to have a low resonance frequency when a thin conductor plate such as an aluminum foil is used as its material. Therefore, in general, a bending process as shown in FIG. 5 is performed.
In FIG. 5, the ribbon-shaped diaphragm 103 is formed with a forming portion 114 that is bent in a bellows shape along the short side direction (width direction) to increase the substantial length. Such a forming portion 114 can be formed relatively easily by pressing and bending a ribbon-like conductor thin plate against a gear-shaped molded member, for example.
However, the ribbon diaphragm subjected to such a bending process is not preferable because the whole is easily stretched. In particular, the center portion of the ribbon diaphragm is easily extended.

Therefore, as shown in FIG. 6, a ribbon-shaped diaphragm that has been bent so that the main part does not extend has been proposed.
In FIG. 6, the ribbon-shaped diaphragm 123 has a first forming portion 133 in which a main vibration portion 123 a that receives a sound wave and vibrates in a magnetic field is bent in a bellows shape along the length direction. Further, edge portions 123b and 123b located at both ends in the length direction of the main vibration portion 123a have second forming portions 134 that are bent in a bellows shape along the short direction (width direction). By having such a first forming portion 133, the main central portion of the ribbon diaphragm does not extend in the longitudinal direction, so that the occurrence of failure can be prevented to some extent.
As an example, a ribbon-shaped diaphragm that has been press-molded has been proposed (see Patent Document 1).

However, the edge portion 123b is formed so that the main vibration portion 123a can move easily, but is easily plastically deformed. When the edge portion 123b is plastically deformed, the ribbon microphone breaks down.
Further, the edge portion 123b is more likely to resonate abnormally than the main vibration portion 123a when a sound wave is applied. This abnormal resonance is the same as the abnormal resonance of the sub-dome of the dynamic microphone. For this reason, an incidental sound caused by the material of the ribbon diaphragm is generated. Since the material of the ribbon diaphragm is aluminum, this incidental sound is the same as the sound when the aluminum foil is bent or the edge is lightly played.
Therefore, at present, it is desired for the ribbon microphone to improve plastic deformation and abnormal resonance at the edge portion of the ribbon diaphragm.
JP 59-15395 A

  The present invention has been made in view of the above circumstances, and is a ribbon microphone that reduces the occurrence of failure due to deformation of the edge portion of the ribbon diaphragm and reduces the occurrence of incidental sound due to abnormal resonance of the edge portion. An object is to provide a unit and a ribbon microphone.

A ribbon microphone unit according to the present invention includes at least a pair of magnets that form a magnetic field and a ribbon diaphragm arranged in the magnetic field of the magnet, and the ribbon diaphragm receives an acoustic wave in the magnetic field. A main vibration part that vibrates in the length direction of the main vibration part, and the main vibration part has a bellows shape along the length direction of the ribbon-shaped diaphragm. A first forming portion that is bent; each edge portion includes a second forming portion that is bent in a bellows shape along a short direction of the ribbon diaphragm; The magnets are arranged in parallel along the length direction of the ribbon diaphragm and opposite to both sides of the ribbon diaphragm, and the diaphragm operation is suppressed in at least a part of the second forming portion. Part Form and, the diaphragm suppressing portion is a coating film covering a portion of the second forming part of the surface is mainly characterized in that.

The ribbon microphone unit of the present invention includes a diaphragm on at least a part of a forming portion provided on each edge portion positioned on both ends in the longitudinal direction of a ribbon diaphragm arranged in a magnetic field formed by a pair of magnets. An operation suppressing part is formed.
Therefore, even if a strong impact from outside or an air flow such as wind pressure is applied to the ribbon diaphragm, the diaphragm operation suppressing part relaxes the stress applied to the edge part and suppresses deformation of the edge part. In addition, when a sound wave is applied to the ribbon diaphragm, the vibration that the diaphragm operation suppression unit applies to the edge part can be mitigated, and the resonance of the edge part can be suppressed.
Therefore, it is possible to provide a ribbon microphone unit and a ribbon microphone that reduce the occurrence of failure due to deformation of the edge portion in the ribbon diaphragm and reduce the occurrence of incidental sound due to abnormal resonance of the edge portion.

Hereinafter, embodiments of a ribbon microphone unit according to the present invention will be described in detail with reference to the drawings.
FIG. 1 is a front view showing an example of a ribbon microphone unit of the present invention. FIG. 2 is a longitudinal sectional view taken along the line I-I indicated by a one-dot difference line in FIG.
As shown in FIGS. 1 and 2, the ribbon microphone unit 1 of the present embodiment includes a plate-like support 2, a pair of magnets 4, 4 attached to the support 2, and the magnets 4, 4. A ribbon-shaped diaphragm 3 disposed in the magnetic field. The support 2 has a slit-like window hole in its longitudinal direction, and magnets 4 and 4 are arranged along the side edges of the window hole, and a uniform magnetic field is formed between the magnets 4 and 4. The ribbon diaphragm 3 is arranged such that the vibration direction cuts off the magnetic field formed between the magnets 4 and 4.

Further, as shown in FIG. 3, the ribbon diaphragm 3 includes a main vibration portion 3a that receives a sound wave and vibrates in a magnetic field, and edge portions 3b that are located at both ends in the length direction of the main vibration portion 3a. , 3b.
In FIG. 3, the main vibration portion 3a of the diaphragm 3 has a first forming portion 13 that is bent in a bellows shape along the length direction. On the other hand, each edge part 3b, 3b has the 2nd forming part 14 which performed the bending process to the bellows shape along the transversal direction (width direction). In both the first forming portion 13 and the second forming portion 14, peaks and valleys formed by bending are formed at regular intervals.
By forming the first forming portion 13 and the second forming portion 14 as described above, the ribbon diaphragm 3 can receive a sound wave and easily vibrate in a magnetic field, and the main vibrating portion 3a The possibility of extending in the longitudinal direction can be suppressed.

  The ribbon microphone unit 1 according to the present invention is characterized in that the diaphragm operation suppressing portion 10 is formed at least in part of the second forming portion 14 included in the edge portion 3b. The diaphragm operation suppressing unit 10 may be formed on only one side of the edge portion 3b, or may be formed on both sides.

  The support 2 is a plate-like fixing member to which the magnet 4 is attached. The support 2 may be a so-called yoke. Examples of the material of the support 2 in this case include soft magnetic materials such as iron, blunt iron, silicon iron, and amorphous. Thus, by using the support body 2 as a yoke, the magnetic resistance of the magnetic circuit of the magnets 4 and 4 is lowered, and the magnetic flux density of the magnetic field formed between the magnets 4 and 4 is increased. When the ribbon diaphragm 3 vibrates, the output appearing at both ends of the ribbon diaphragm 3 can be increased.

  The ribbon diaphragm 3 is a movable diaphragm formed in a ribbon shape. The ribbon diaphragm 3 is not particularly limited as long as it is conductive and has a light specific gravity. As a material that meets such conditions, there is an aluminum foil as seen in most conventional ribbon microphones. Therefore, aluminum foil is also used in this embodiment.

  The ribbon-shaped diaphragm 3 is sandwiched between a pair of first sandwiching members 11a and 11b having one end side made of a conductive member, and the other end side is also a pair of first sandwiching members made of a conductive member. It is sandwiched between the two clamping members 12a and 12b. The first holding members 11a and 11b and the second holding members 12a and 12b both support the ribbon-shaped diaphragm 3 in a sandwich shape, facilitate attachment and fixing to the support 2, and the ribbon. It also serves as a spacer for reliably disposing the diaphragm 3 in the magnetic field of the magnet 4.

  Further, a first output terminal 5 made of a conductive member is interposed between the support 2 and one of the first clamping members 11a, and the support 2 and one of the second clamping members 12a are interposed. A second output terminal 6 made of a conductive member is interposed between them. The first output terminal 5 and the second output terminal 6 each output an audio signal generated by the ribbon diaphragm 3.

Furthermore, the first insulating member 11b on the other side is provided with an electrically insulating first pressing member 7 so as to cover it from above, and the second holding member 12b on the other side is also provided from above. A second presser member 8 made of an insulating member is disposed so as to be covered.
The first presser member 7 is attached and fixed to one end of the ribbon diaphragm 3 with respect to the support 2 by tightening with a screw 17, and the second presser member 8 is tightened with a screw 18. Thus, the other end side of the ribbon diaphragm 3 is attached and fixed to the support 2.

Accordingly, the first output terminal 5, one first clamping member 11a, one end of the ribbon-shaped diaphragm 3, the other first clamping member 11b, and the first pressing member 7 are arranged in this order on one end side of the support body 2. They are arranged in layers. On the other hand, on the other end side of the support 2, the second output terminal 6, one second clamping member 12a, the other end of the ribbon diaphragm 3, the other second clamping member 12b, the second pressing member 8, Are arranged in order.
The first clamping members 11a and 11b and the first output terminal 5 are both made of a conductive member, so that either the first clamping member 11a or the other first clamping member 11b You may comprise integrally so that it may serve as one output terminal. In addition, since the second holding members 12a and 12b and the second output terminal 6 are both made of a conductive member, either one of the second holding members 12a or the other second holding member 12b You may comprise integrally so that it may serve as two output terminals. As a result, the number of parts can be reduced, the configuration can be simplified, and assembly can be facilitated.

The magnets 4 and 4 are permanent magnets joined to the support 2 respectively. The magnets 4 and 4 are magnetized so that an N pole and an S pole are formed in the width direction.
The magnets 4, 4 are arranged in parallel along the length direction of the ribbon diaphragm 3 and opposite to both sides of the ribbon diaphragm 3. Further, an appropriate slit-shaped window hole exists between the magnets 4 and 4 and the side surface of the ribbon diaphragm 3. Therefore, a magnetic field is formed in the space where the magnets 4 and 4 are opposed, and at least the main vibration part 3a of the ribbon diaphragm 3 is disposed in parallel with the magnetic field direction.
When the ribbon diaphragm 3 receives a sound wave, it vibrates in a direction crossing the magnetic field and generates an electric signal corresponding to the sound wave.

The diaphragm operation suppressing unit 10 may cover the surface of the second forming unit 14.
As a result, the diaphragm operation suppressing portion 10 can be easily formed in the second forming portion 14 without subjecting the second forming portion 14 itself to processing such as deformation or notch.

Moreover, it is desirable that the diaphragm operation suppressing unit 10 is a coating film.
That is, as a method of covering the surface of the second forming portion 14, there is a means for attaching a film, a sheet material or the like to the edge portion 3b. However, the coating film formed by the means for applying the resin agent can cover the second forming portion 14 more easily, thinly, and with good adhesion. In addition, the operation of the diaphragm can be suppressed and the diaphragm operation suppressing unit 10 can be repaired by adjusting the thickness of the coating film, the portion to be applied, and the like.

Furthermore, it is more desirable that the diaphragm operation suppressing unit 10 has an elastic restoring force.
Thereby, the diaphragm operation | movement suppression part 10 can suppress effectively the plastic deformation of the edge part 3b, without preventing the operation | movement of the main vibration part 3a of the ribbon-shaped diaphragm 3. FIG.

  The vibration plate operation suppressing unit 10 as described above can be formed by applying a polymer material. Examples of the material that satisfies the conditions of the diaphragm operation suppressing unit 10 include silicone rubber, particularly room temperature vulcanization type silicon rubber (silicon RTV rubber). Examples of silicon RTV (Room Temperature Vulcanizing) rubber include KE3475 manufactured by Shin-Etsu Chemical Co., Ltd.

In the ribbon microphone unit 1 configured as described above, the main vibration portion 3a of the ribbon diaphragm 3 vibrates according to the sound wave when it receives the sound wave. When the ribbon diaphragm 3 which is a conductor vibrates in the magnetic field, the ribbon diaphragm 3 crosses the magnetic field to generate a signal current. The signal current is further generated from both ends of the ribbon diaphragm 3 by the first. It is output through the output terminal 5 and the second output terminal 6.
In the ribbon microphone unit 1, even if a strong impact or an air current such as wind pressure is applied to the ribbon diaphragm 3 from the outside, the diaphragm operation suppression unit 10 relaxes the stress applied to the edge portion 3 b, and the edge portion 3 b Suppresses plastic deformation. In addition, when a sound wave is applied to the ribbon diaphragm 3, the diaphragm operation suppression unit 10 relaxes the vibration applied to the edge part 3b and suppresses abnormal resonance of the edge part 3b.

  Therefore, by incorporating the ribbon microphone unit 1 configured in this way into a microphone case having a head case made of metal mesh or punching metal that takes in sound waves and protects internal components, the edge portion is deformed. It is possible to provide a ribbon microphone that reduces the occurrence of failures and reduces the occurrence of incidental sounds due to abnormal resonance of the edge portion.

It is a front view which shows the Example of the ribbon microphone unit which concerns on this invention. It is a longitudinal cross-sectional view along the II line | wire shown in FIG. It is a perspective view which shows the example of the ribbon-type diaphragm applicable to the ribbon microphone unit which concerns on this invention. It is a front view which shows an example of the conventional ribbon microphone unit. It is a longitudinal cross-sectional view along the II-II line | wire shown in FIG. It is a perspective view explaining the structure of the conventional ribbon type diaphragm.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ribbon microphone unit 2 Support body 3 Ribbon-shaped diaphragm 3a Main vibration part 3b Edge part 4 Magnet 5 First output terminal 6 Second output terminal 7 First presser member 8 Second presser member 10 Diaphragm operation suppression part 11a, 11b 1st clamping member 12a, 12b 2nd clamping member 13 1st forming part 14 2nd forming part

Claims (3)

A pair of magnets that form a magnetic field;
A ribbon diaphragm arranged in the magnetic field of the magnet;
Comprising at least
The ribbon diaphragm is composed of a main vibration portion that receives a sound wave and vibrates in a magnetic field, and edge portions that are located on both ends in the length direction of the main vibration portion, respectively.
The main vibration part has a first forming part that is bent in a bellows shape along the length direction of the ribbon diaphragm,
Each of the edge portions has a second forming portion that is bent in a bellows shape along the short direction of the ribbon diaphragm,
The pair of magnets are arranged in parallel along the length direction of the ribbon diaphragm and opposite to both sides of the ribbon diaphragm,
Forms at least a part vibration plate operation inhibiting portion of the second forming unit,
The diaphragm operation suppressing part is a coating film that covers a part of the surface of the second forming part.
Ribbon microphone unit. The diaphragm operation suppression unit, a ribbon microphone unit according to claim 1, wherein that you have an elastic restoring force. Ribbon microphone, characterized in that it comprises a ribbon microphone unit according to any one of claims 1 or 2.

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