JP2008259003A - Diaphragm for dynamic microphone and manufacturing method thereof, and dynamic microphone - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate abnormal resonance caused by reinforcing resin when mechanical strength is enhanced by applying the reinforcing resin into an annular groove formed between a center dome and a sub-dome from a top surface side of a diaphragm. <P>SOLUTION: A diaphragm for a dynamic microphone which has the center dome 11 in a nearly convex spherical shape and the sub-dome 12 which is annularly coupled to a circumference of the center dome 1 in one body and sectioned in a nearly convex curve shape and also has a voice coil 13 fitted to a reverse surface side of a boundary part between the center dome 11 and sub-dome 12 through an adhesion means has the reinforcing resin 41 charged over the entire circumference in the annular groove 14, formed on the top surface side at the boundary part between the center dome 11 and sub-dome 12, to gradually decrease in thickness from the groove bottom onto skirt parts of the domes 11 and 12. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a diaphragm for a dynamic microphone, a method for manufacturing the same, and a dynamic microphone. More specifically, the present invention relates to a technology that can reinforce a voice coil mounting portion even when the diaphragm is mounted on a magnetic generation circuit of a dynamic microphone. It is about.

  FIG. 4 shows a diaphragm that is usually used in a dynamic microphone. The diaphragm 10 has a center dome 11 having a substantially convex spherical shape, and a sub dome 12 having a substantially convex curved surface in a cross section integrally provided as a ring around the center dome 11 so as to elastically support the diaphragm. (For example, refer to Patent Document 1). As the material, a synthetic resin film such as polyethylene or polyester is usually used.

  On the back side of the diaphragm 10, a power generation voice coil 13 is attached to a boundary portion between the center dome 11 and the sub dome 12 via an adhesive, for example. The voice coil 13 is disposed in a magnetic gap of a magnetism generation circuit (not shown), and generates power by vibrating in the magnetic gap together with the center dome 11 by an incoming sound wave, and converts the sound wave into an audio signal.

  Therefore, the center dome 11 plays an important role for the conversion efficiency and frequency response in the dynamic microphone, and in order to obtain a good frequency response particularly at a high frequency, the center dome 11 has a high mechanical strength, In addition, it is necessary to mechanically and firmly couple with the voice coil 13.

  In other words, the diaphragm 10 is driven by sound waves, but when the mechanical strength of the center dome 11 is low, a transmission loss occurs to the voice coil 13 due to the deformation of the center dome 11.

  Therefore, as an example of a method for increasing the mechanical strength of the center dome, in Patent Document 2, a reinforcing member made of a polyethylene film is pasted on the center dome via a double-sided adhesive tape, so that the center dome has a double structure. It has been proposed.

  However, according to this method, a double-sided adhesive tape and a reinforcing member are required separately, and the number of work steps for attaching the reinforcing member is increased, which is not preferable in terms of cost.

  As another method for increasing the mechanical strength of the center dome, Patent Document 3 discloses that the voice coil is centered with a first ultraviolet curable resin having a relatively high viscosity before curing and a relatively low hardness after curing. It has been proposed to integrally form a reinforcing resin layer made of a second ultraviolet curable resin that adheres to the dome and has a relatively low viscosity before curing and a relatively high hardness after curing on the inner surface of the center dome. .

  According to this, a diaphragm for a dynamic microphone having a high mechanical strength and excellent impact resistance can be obtained, but the portion where the reinforcing resin layer is formed is the back surface of the center dome. The diaphragm must be processed before it can be incorporated into the magnetic generation circuit of the microphone unit.

  That is, when the diaphragm is already incorporated in the magnetism generation circuit of the microphone unit, the invention described in Patent Document 3 is used in order to make the microphone unit a high-quality model according to the user level, for example. In order to apply, it is necessary to remove the diaphragm from the magnetism generating circuit, form a reinforcing resin layer on the back surface of the center dome, and incorporate it again in the magnetism generating circuit.

  On the other hand, Patent Document 4 proposes forming a thin film of a reinforcing agent for enhancing rigidity in an annular groove provided at the boundary between the center dome and the sub dome.

  In Patent Document 4, for example, a polyester-based or acrylic-based adhesive, Vironal (trade name), a biocellulose solution, or the like is used as the reinforcing agent, and this reinforcing agent is applied to a predetermined portion in the annular groove. Then, for example, it is naturally dried by being left at room temperature of about 30 to 40 ° C. for about 1 hour to form a thin film.

  According to the invention described in Patent Document 4, a thin film for reinforcement is formed from the upper surface side of the diaphragm without bothering to remove the diaphragm even when the diaphragm is already incorporated in the magnetism generating circuit of the microphone unit. There are problems in the following points.

  That is, the reinforcing thin film in Patent Document 4 has a substantially uniform film thickness, and apparently rises at the bottom of the sub dome as if the film was attached.

  As a result, the mechanical impedance becomes discontinuous because the hardness changes abruptly between the portion where the thin film for reinforcement is present and the portion where the thin film for reinforcement is not present, and this causes abnormal resonance of the diaphragm. .

JP-A-4-115696 JP-A-8-23596 JP 2005-184331 A Japanese Patent Laid-Open No. 10-257589

  Therefore, an object of the present invention is to apply a reinforcing resin in an annular groove existing between the center dome and the sub dome from the upper surface side of the diaphragm in the dynamic microphone diaphragm integrally including the center dome and the sub dome. Thus, in increasing the mechanical strength, it is to prevent abnormal resonance from occurring due to the reinforcing resin.

  In order to solve the above-described problems, the present invention provides a center dome having a substantially convex spherical shape and a substantially convex cross section integrally connected as a ring around the center dome, as described in claim 1. A diaphragm for a dynamic microphone, comprising: a sub dome having a curved surface; and a voice coil attached to a back surface side of a boundary portion between the center dome and the sub dome via an adhesive means. The reinforcing resin is filled over the entire circumference of the annular groove formed on the upper surface side at the boundary part of the boundary so that the thickness gradually decreases as it rises from the groove bottom to the hem of each dome. It is a feature.

  Further, according to the present invention, a center dome having a substantially convex spherical shape, and a substantially convex curved surface having a cross section integrally provided as a ring around the center dome are provided. In the method for manufacturing a diaphragm for a dynamic microphone, comprising a sub dome, wherein a voice coil is attached to a back surface side of a boundary portion between the center dome and the sub dome via an adhesive means, the boundary between the center dome and the sub dome After applying the reinforcing resin to a predetermined portion of the skirt of the center dome located on the inner diameter side of the annular groove formed on the upper surface side in the portion, the diaphragm is rotated to allow the reinforcing resin to be placed in the groove. It is characterized by filling over the entire circumference.

  In the method for manufacturing a diaphragm for a dynamic microphone according to claim 2, as described in claim 3, an ultraviolet curable resin that does not contain a volatile component is used as the reinforcing resin, and the reinforcing resin is disposed in the entire groove. After filling the circumference, it is preferable to cure the reinforcing resin by irradiation with ultraviolet rays.

  According to a fourth aspect of the present invention, there is provided a dynamic microphone including the dynamic microphone diaphragm according to the first aspect or the dynamic microphone diaphragm manufactured according to any one of the second and third aspects. It is included in the present invention.

  According to the present invention, the reinforcing resin enters the bottom of each dome from the groove bottom over the entire circumference in the annular groove formed on the upper surface side of the diaphragm at the boundary portion between the center dome and the sub dome. Therefore, since the thickness is gradually reduced, the mechanical impedance at the skirt of the sub dome does not change abruptly, thereby preventing abnormal resonance of the diaphragm.

  In addition, even when the diaphragm is already incorporated in the magnetism generation circuit of the microphone unit, the diaphragm can be reinforced from the upper surface side of the diaphragm without bothering to remove the diaphragm.

  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 a cross-sectional view showing a state in which a diaphragm of a dynamic microphone is incorporated in a microphone case together with a magnetism generating circuit, and FIG. 2 is a schematic diagram showing a diaphragm according to an embodiment of the present invention reinforced by a reinforcing resin. FIG. 3 is a sectional view showing a dynamic microphone provided with a diaphragm according to an embodiment of the present invention.

  As shown in FIG. 1, the dynamic microphone includes a diaphragm 10 and a magnetism generation circuit 20 and a microphone housing 30 that supports them as a basic configuration.

  As described above with reference to FIG. 4, the diaphragm 10 has a center dome 11 having a substantially convex spherical shape, and a cross section integrally provided as a ring around the center dome 11 so as to elastically support the center dome 11. A sub dome 12 having a substantially convex curved surface is formed, and the whole is made of a synthetic resin film such as polyethylene or polyester.

  On the back side of the diaphragm 10, a power generation voice coil 13 is attached to a boundary portion between the center dome 11 and the sub dome 12 via an adhesive, for example.

  The magnetism generating circuit 20 is formed in a disk-like permanent magnet 21, a center pole piece 22 provided on one pole side of the permanent magnet 21, and a dish provided on the other pole side of the permanent magnet 21. And a ring yoke 24 that is disposed at the upper end of the yoke 23 and forms a magnetic gap G with the center pole piece 22.

  The microphone casing 30 is formed of a cylindrical body having a rear air chamber 31 having a predetermined volume, and the magnetism generation circuit 20 is mounted on the rear air chamber 31. The diaphragm 10 is supported by the upper end surface of the microphone housing 30 at the peripheral portion of the sub dome 20 so that the voice coil 13 vibrates in the magnetic gap G.

  The rear air chamber 31 includes vent holes 31a and 31b covered with acoustic resistance materials at both upper and lower ends, and the upper vent hole 31a, the opening 23a formed in the yoke 23, and the magnetic gap G are provided. The diaphragm 10 communicates with the space on the back side.

  In the present invention, the center dome 11 is reinforced in a state where the diaphragm 10 is incorporated in the microphone housing 30 together with the magnetism generation circuit 20. This reinforcement processing is performed by filling a reinforcing resin into an annular groove 14 existing at the boundary between the center dome 11 and the sub dome 12 from the upper surface side of the diaphragm 10.

  Therefore, as shown in FIG. 1, the reinforcing resin 41 is applied to the skirt of the center dome 11 on the inner diameter side of the groove 14 of the diaphragm 10 using, for example, a dispenser 40. You may apply | coat to cyclic | annular form and may apply | coat in several places.

  The reinforcing resin 41 used may be a thermosetting resin, but is preferably an ultraviolet curable resin that does not contain a volatile component. In this example, UV curable resin U-1430 (trade name) manufactured by Chemitech is used.

  After applying the reinforcing resin 41, the entire microphone casing 30 is rotated about its axis, and the reinforcing resin 41 is filled into the groove 14 by centrifugal force. If an ultraviolet curable resin that does not contain a volatile component is used for the reinforcing resin 41, the fluidity is good, so that the filling into the grooves 14 can be performed smoothly.

  FIG. 2 shows a state in which the reinforcing resin 41 is filled in the groove 14. When the rotation is stopped, the reinforcing resin 41 accumulates in the groove 14 by gravity, so that the reinforcing resin 41 is filled so that the thickness gradually decreases as it rises from the bottom of the groove to the bottom of each dome 11, 12.

  Thereafter, preferably, when the filling of the reinforcing resin 41 is stabilized, the reinforcing resin 41 is cured by irradiation with ultraviolet rays. Thereby, since the mechanical impedance in the skirt part of the sub dome 12 does not change rapidly, abnormal resonance of the diaphragm 10 is prevented.

  Note that the spread of the reinforcing resin 41 toward the sub dome 12 can be appropriately controlled by controlling the rotation speed and the rotation time. After the reinforcing resin 41 is cured, as shown in FIG. 3, the assembly is completed by covering the upper end of the microphone casing 30 with the resonator 32 so as to cover the diaphragm 10.

  Although the embodiment of the present invention has been described based on the illustrated example, the manufacturing method of the present invention may of course be applied to the diaphragm 10 before being incorporated in the microphone casing 30. Further, the configurations of the magnetism generation circuit 20 and the microphone casing 30 may be arbitrarily changed.

Sectional drawing which shows the state with which the diaphragm of the dynamic microphone was integrated in the microphone housing | casing with the magnetism generation circuit. 1 is a schematic cross-sectional view showing a diaphragm according to an embodiment of the present invention. Sectional drawing which shows the dynamic microphone provided with the diaphragm which concerns on the said embodiment. A typical sectional view showing a diaphragm usually used for a dynamic microphone.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Diaphragm 11 Center dome 12 Sub dome 13 Voice coil 14 Annular groove 20 Magnetization circuit 21 Permanent magnet 22 Center pole piece 23 Yoke 24 Ring yoke 30 Microphone housing 31 Rear air chamber 32 Resonator 41 Reinforcing resin

Claims (4)

A center dome having a substantially convex spherical shape, and a sub dome having a substantially convex curved surface in section integrally connected as a ring around the center dome, and a back surface of a boundary portion between the center dome and the sub dome In the diaphragm for a dynamic microphone in which a voice coil is attached to the side via an adhesive means,
The reinforcing resin gradually decreases in thickness as it goes up from the groove bottom to the hem of each dome over the entire circumference in the annular groove formed on the upper surface at the boundary between the center dome and the sub dome. A diaphragm for a dynamic microphone, characterized by being filled in A center dome having a substantially convex spherical shape, and a sub dome having a substantially convex curved surface in section integrally connected as a ring around the center dome, and a back surface of a boundary portion between the center dome and the sub dome In the manufacturing method of the diaphragm for a dynamic microphone in which a voice coil is attached to the side via an adhesive means,
After applying a reinforcing resin to a predetermined portion of the skirt of the center dome located on the inner diameter side of the annular groove formed on the upper surface side at the boundary between the center dome and the sub dome, the diaphragm is rotated. A method for manufacturing a diaphragm for a dynamic microphone, wherein the reinforcing resin is filled over the entire circumference in the groove.   3. The ultraviolet curable resin containing no volatile component is used as the reinforcing resin, and the reinforcing resin is cured by irradiating with ultraviolet rays after filling the reinforcing resin over the entire circumference of the groove. A manufacturing method of the diaphragm for dynamic microphones described in 1.   A dynamic microphone comprising the dynamic microphone diaphragm according to claim 1 or the dynamic microphone diaphragm manufactured according to any one of claims 2 and 3 as the diaphragm.

Images