JP4578986B2 - Dynamic microphone unit and manufacturing method thereof - Google Patents

Description

  The present invention relates to a dynamic microphone unit and a method for manufacturing the same, and more particularly to a technique for improving a frequency response by applying a vibration-damping peripheral treatment agent to a diaphragm.

  A dynamic microphone unit is a magnetic circuit having a magnetic gap between a diaphragm to which a voice coil is integrally attached, a pole piece connected to one pole of a permanent magnet, and a ring yoke connected to the other pole. The electroacoustic transducer converts a sound wave into an electric signal by vibrating the voice coil together with the diaphragm in the magnetic gap, and is also called an electrodynamic type.

  The diaphragm used in the dynamic microphone unit includes a center dome and a sub dome integrally connected to the outer periphery of the center dome to support the center dome, and is generally composed of a synthetic resin thin film such as a polyethylene film. A voice coil is integrally attached to the boundary between the center dome and the sub dome with an adhesive.

  By the way, it is possible to collect sound at a low frequency by lowering the resonance frequency of the low range of the diaphragm. However, since the control method of the unidirectional dynamic microphone is mainly mass control, the resonance frequency of the diaphragm There are two methods for reducing the voice coil: a method in which the voice coil is made heavy, and a method in which the stiffness of the sub-dome is made small (spring property is weakened).

  However, the method of making the voice coil heavier is not preferable for a handheld microphone because bundling noise caused mainly by rubbing the microphone grip with a hand increases.

  In addition, in order to reduce the stiffness of the sub dome, there are, for example, a method of reducing the film thickness of the sub dome and a method of increasing the radius of curvature, but in any case, the mechanical strength of the sub dome will be weakened, As a result, abnormal resonance is likely to occur in the frequency response band of 2 to 8 kHz.

  In order to prevent this abnormal resonance, the invention described in Patent Document 1 includes a solution containing an organic solvent such as trichloroethane in synthetic rubber or acrylic rubber at the apex of the sub dome that elastically supports the center dome. The vibration-damping peripheral treatment agent thus applied is applied to a plurality of locations in a pattern having an appropriate width in the radial direction and an appropriate length in the circumferential direction.

Japanese Utility Model Publication No. 5-43694

  According to the invention described in Patent Document 1, by applying the peripheral treatment agent to the sub dome at an appropriate interval, the change in stiffness of the diaphragm is extremely small, abnormal resonance at a specific frequency is prevented, and low frequency It is possible to reliably collect low-pitched sound by preventing sudden attenuation of the limit.

  However, since the peripheral treatment agent is applied to the apex portion of the sub dome, the peripheral treatment agent easily flows to the outside or the inside using the apex portion of the sub dome as a watershed, and whether it flows to either of them is sometimes Therefore, there is a problem that the frequency response varies.

  Accordingly, an object of the present invention is to provide a dynamic microphone unit with uniform quality by reliably applying a predetermined amount of a peripheral treatment agent for vibration damping to a predetermined position on a sub-dome that elastically supports the center dome. Is to provide.

In order to solve the above-mentioned problem, the invention according to claim 1 is a diaphragm comprising a center dome having a voice coil, a sub-dome having a circular arc section integrally provided on the outer periphery of the center dome, and a permanent magnet. A unit case having a magnetic circuit having a magnetic gap of a predetermined width between a pole piece connected to one pole and a ring yoke connected to the other pole, wherein the voice coil vibrates in the magnetic gap. In the dynamic microphone unit in which the outer peripheral portion of the sub dome is supported by the unit case so as to be positioned, the dynamic microphone unit is made of a resin material formed annularly on the outer peripheral portion of the sub dome having the circular arc shape in cross section. A weir having a predetermined height, and a vibration-damping peripheral treatment agent applied between the top of the sub-dome and the weir. It is characterized by a door.

According to a second aspect of the present invention, there is provided a diaphragm including a center dome having a voice coil and a sub-dome having a circular arc section integrally provided on the outer periphery of the center dome, and connected to one pole of a permanent magnet. A unit case having a magnetic circuit having a magnetic gap of a predetermined width between the pole piece and the ring yoke connected to the other pole, and the voice coil is positioned so as to vibrate within the magnetic gap. In the method of manufacturing the dynamic microphone unit in which the outer peripheral portion of the sub dome is supported on the unit case, the resin material is provided over the entire circumference of the outer peripheral portion of the arc-shaped sub dome supported by the unit case. After forming a height weir in an annular shape, a peripheral treatment agent for vibration suppression is placed between the top of the sub dome and the weir. It is characterized in that the cloth.

  According to the present invention, a weir having a predetermined height is formed in an annular shape around the entire circumference of the outer periphery of the sub dome, and a peripheral treatment agent for damping is applied between the weir and the top of the sub dome. As a result, the peripheral treatment agent does not flow out over the weir, and therefore the peripheral treatment agent for vibration damping can be reliably applied to the sub dome at a predetermined amount.

  Next, an embodiment of the present invention will be described with reference to FIGS. 1 to 3, but the present invention is not limited to this. FIG. 1 is an exploded cross-sectional view showing a basic configuration of the dynamic microphone unit, and FIGS. 2 and 3 are cross-sectional views for explaining a process of applying a peripheral treatment agent for vibration suppression.

  As shown in FIG. 1, the dynamic microphone unit 1 includes a diaphragm 10, a unit case 20, and a resonator 30 as a basic configuration. The diaphragm 10 includes a center dome 11 and a sub dome 12 integrally provided around the center dome 11 so as to support the center dome 11.

  The center dome 11 and the sub dome 12 can be integrally formed by placing a synthetic resin thin film such as a polyethylene film on a mold (not shown) and performing heat pressing. The voice coil 13 is integrally fixed to the boundary portion between the center dome 11 and the sub dome 12 via an adhesive. The dome curvatures of the center dome 11 and the sub dome 12 may be arbitrarily selected.

  The unit case 20 includes a housing 21 made of a nonmagnetic material and formed in a substantially cylindrical shape, and a magnetic circuit 22 is supported in the housing 21. Since the dynamic microphone unit 1 is unidirectional, the housing 21 is provided with a rear acoustic terminal 211 having a side damper 212 and an acoustic resistance member 215. A terminal plate 213 to which the lead wire of the voice coil is connected is attached to the outside of the housing 21, and a rear air chamber 214 having a predetermined volume is provided in the housing 21.

  The magnetic circuit 22 is formed in a disk-like permanent magnet 221, a center pole piece 222 connected to one pole of the permanent magnet 221, and a dish-like shape connected to the other pole of the permanent magnet 221. In this example, a ring yoke 224 that forms a magnetic gap G having a predetermined width with the center pole piece 222 is provided at the open end of the yoke member 223.

  The diaphragm 10 is placed on the unit case 20 so that the voice coil 13 enters the magnetic gap G, and then the resonator 30 is further placed on the diaphragm 10. The resonator 30 includes a front acoustic terminal 31 covered with a mesh member 311 such as a wire mesh, and sandwiches the outer peripheral portion 121 of the sub dome 12 with the housing 21. The outer peripheral portion 121 of the sub dome 12 may be fixed to the unit case 20 with an adhesive. This fixing may be either temporary fixing or permanent fixing.

Thereby, in the dynamic microphone unit 1, the center dome 11 of the diaphragm 10 is elastically supported via the sub dome 12 , and the sound wave coming from the front acoustic terminal 31 and the acoustic signal 215 from the rear acoustic terminal 211. As a result, the voice coil 13 generates a current due to electromagnetic induction.

  In this way, sound waves are converted into electrical signals. However, if the stiffness of the sub-dome 12 is reduced in order to lower the resonance frequency in the low range, abnormal resonance occurs in the frequency response portion of 2 to 8 kHz as described above. Sometimes. In order to prevent this, a vibration-suppressing peripheral treatment agent is applied to the sub-dome 12, but the following method is adopted in the present invention in order to reliably apply the peripheral treatment agent to a predetermined position by a predetermined amount. This will be described with reference to FIGS.

  The peripheral treatment agent may be applied in a state before the diaphragm 10 is put on the unit case 20, but in this case, the magnetic circuit 22 of the unit case 20 is exposed to the outside, and dust or the like is present in the magnetic gap G. Since foreign matter may cause entry failure, it is preferable to apply the peripheral treatment agent with the diaphragm 10 covered on the unit case 20 as shown in FIG.

  In the present invention, the peripheral treatment agent is applied in two steps. First, as shown in FIG. 2, as a first step, an annular weir 41 having a predetermined height is made over the entire circumference of the outer peripheral portion 121 of the subtome 12. In order to form the weir 41 in an annular shape, a spin coater having a dispenser may be used. In that case, the dispenser side may be revolved with respect to the unit case 20, or the position of the dispenser may be fixed and the unit case 20 side may be rotated.

  The weir 41 is preferably formed of a peripheral treatment agent, but a resin other than the peripheral treatment agent may be used. Examples of the peripheral treatment agent for vibration suppression to be applied include a product name 5X634A (ultraviolet curable resin) manufactured by Chemtech, a product name 223B (rubber adhesive) manufactured by Cemedine, and the like. .

  Next, after the weir 41 is cured, as shown in FIG. 3, a vibration-damping peripheral treatment agent 42 is applied between the top portion 122 of the subtome 12 and the weir 41 as the second step. The peripheral treatment agent 42 is preferably applied by the above-described rotary coater, but it may be arbitrarily determined whether to apply continuously or partially discontinuously over the entire circumference of the subtome 12.

  In any case, according to the present invention, since the weir 41 is formed first, the peripheral treatment agent 42 does not flow out of the sub dome 12. Further, since the peripheral treatment agent 42 is applied between the top portion 122 of the sub-dome 12 and the weir 41, and the amount of application can be quantified, mass production of dynamic microphone units with uniform quality without variation in frequency response is performed. be able to.

  The height of the weir 41 may be determined in relation to the application amount of the peripheral treatment agent 42. In addition, the resonator 30 is covered after the peripheral treatment agent 42 is applied, but it is preferable that the position of the weir 41 is located inside the avoidance of the position sandwiched by the resonator 30.

FIG. 2 is an exploded cross-sectional view showing a basic configuration of a dynamic microphone unit. Sectional drawing which shows the 1st process of the manufacturing method by this invention. Sectional drawing which shows the 2nd process of the manufacturing method by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Dynamic microphone unit 10 Diaphragm 11 Center dome 12 Sub dome 121 Outer peripheral part 122 Top part 13 Voice coil 20 Unit case 21 Housing 211 Back acoustic terminal 22 Magnetic circuit 221 Permanent magnet 222 Center pole piece 223 York member 224 Ring yoke 30 Resonator 31 Front Acoustic terminal 41 Weir 42 Peripheral treatment agent for damping G Magnetic gap

Claims (2)

A diaphragm having a center dome having a voice coil and a sub-dome having a circular arc cross section integrally connected to the outer periphery of the center dome, a pole piece connected to one pole of the permanent magnet, and the other pole A unit case having a magnetic circuit having a magnetic gap of a predetermined width between the ring yoke and the unit case, the outer peripheral portion of the sub-dome being positioned so as to be able to vibrate within the magnetic gap. In the dynamic microphone unit that is supported by
A weir having a predetermined height made of a resin material formed in an annular shape over the entire circumference of the sub-dome having an arc-shaped cross section, and a vibration-damping periphery applied between the top of the sub-dome and the weir A dynamic microphone unit comprising a treatment agent. A diaphragm having a center dome having a voice coil and a sub-dome having a circular arc cross section integrally connected to the outer periphery of the center dome, a pole piece connected to one pole of the permanent magnet, and the other pole A unit case having a magnetic circuit having a magnetic gap of a predetermined width between the ring yoke and the unit case, the outer peripheral portion of the sub-dome being positioned so as to be able to vibrate within the magnetic gap. In the method of manufacturing a dynamic microphone unit supported by
A weir having a predetermined height is formed annularly with a resin material over the entire circumference of the outer peripheral portion of the arc-shaped subdome supported by the unit case, and then vibration is suppressed between the top of the subdome and the weir. A method for manufacturing a dynamic microphone unit, comprising applying a peripheral treatment agent.

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