WO2010150660A1 - Method for producing vibrating membrane unit - Google Patents

Abstract

Provided is a method for producing a vibrating membrane unit (1) used for a microphone, the vibrating membrane unit being provided with: a tubular support member (11) made of resin, which opens in at least one side in an axial direction thereof; and a vibrating membrane (21) fixed to an opening peripheral portion of a first end face (12) in such a manner as to cover an opening of the first end face (12), the first end face (12) being an end face of the tubular support member (11) in the above one side thereof in the axial direction thereof. The method comprises: a fixing step in which the vibrating membrane (21) is brought into a state fixed to the opening peripheral portion of the first end face (12) of the tubular support member (11); and a tension providing step in which, after the foregoing fixing step, a predetermined tension is provided to the vibrating membrane (21) by utilizing radially outward deformation of the tubular support member (11).

Description

Manufacturing method of diaphragm unit

The present invention provides a cylindrical support member made of resin having an opening in at least one side in the axial direction, and an opening peripheral portion of a first end face that is an end surface on the one side in the axial direction of the cylindrical support member. It belongs to the technical field regarding the manufacturing method of the diaphragm unit used for the microphone provided with the diaphragm fixed so as to cover the opening.

Generally, a tension is applied to a diaphragm used for a microphone so that a change in sound pressure can be faithfully converted into an electric signal. As a method of applying tension to the vibration membrane in this way, a method of fixing the vibration membrane to the opening peripheral portion of the opening end surface of the cylindrical support member by bonding or the like while pulling the outer peripheral portion of the vibration membrane radially outward. There is.

Further, for example, in Patent Document 1, in a condenser microphone unit having a diaphragm and a fixed pole that is disposed opposite to the diaphragm and forms a capacitor with the diaphragm, the diaphragm is fixed to the support ring by bonding. Later, when a protrusion is thermoformed on the surface of the diaphragm opposite to the support ring, the diaphragm is installed in the case, and when the fixed pole is installed on the diaphragm, the protrusion is fixed to the diaphragm. It is disclosed that a tension is applied to the diaphragm while maintaining a distance from the pole.

Further, for example, in Patent Document 2, a ring member in which a screw part is formed on an inner peripheral surface and a vibration film is fixed to an opening end is screwed to a housing member in which a screw part is formed on an outer peripheral part. It is disclosed that the membrane support portion abuts on the vibrating membrane and applies tension to the vibrating membrane.

Patent Document 3 includes a magnetically permeable or conductive diaphragm that vibrates in response to an acoustic signal, an LC oscillation circuit, a coil that constitutes the LC oscillation circuit, and a circuit that demodulates the oscillation wave. A semiconductor in which the vibration film and the coil are held at a predetermined interval so that the inductance of the coil changes due to vibration, and the change in the oscillation frequency of the LC oscillation circuit that changes due to the change in the inductance is demodulated. A microphone is disclosed. The vibrating membrane of the semiconductor microphone of this Patent Document 3 is held by two upper and lower cylindrical holding member portions. Usually, in order to apply tension to the vibrating membrane, a lower side of the lower holding member portion is used. A method is adopted in which a tension adjusting ring is press-fitted into the holding member from the opening, and the outer peripheral portion of the vibration film is pushed up by the tension adjusting ring. In this case, the magnitude of the tension applied to the vibration film is determined by the vertical position of the tension adjustment ring.

JP 2008-147743 A JP 11-69493 A JP 2005-143065 A

However, in the method of fixing the diaphragm to the cylindrical support member while pulling the outer peripheral edge of the diaphragm to the outside in the radial direction, a grip allowance is required to pull the diaphragm, and the grip allowance is obtained by using a microphone. From the viewpoint of downsizing in the radial direction, the cutting is generally performed after the vibration membrane is fixed. For this reason, an extra work of cutting the vibration membrane after fixing it to the cylindrical support member is necessary, and after fixing to the cylindrical support member, the cylindrical support member exists, and thus the cylindrical support member is present. It becomes harder to cut than before fixing to the member.

Therefore, as shown in Patent Documents 1 and 2, after the diaphragm is fixed to the cylindrical support member, the diaphragm is pressed in the thickness direction (the axial direction of the cylindrical support member). It is desirable to apply tension to the.

However, in such a method of applying tension to the vibrating membrane by pressing the vibrating membrane in the thickness direction, the axial position of the vibrating membrane in the cylindrical support member changes due to the pressing of the vibrating membrane. In particular, in the semiconductor microphone disclosed in Patent Document 3, since the distance between the vibration film and the coil is related to the acoustic detection accuracy, it is necessary to maintain the distance with high precision, but the vibration film is pressed in the thickness direction. In this method, it is difficult to maintain the above-mentioned interval with high accuracy.

The present invention has been made in view of such points, and the object of the present invention is as a method of manufacturing a diaphragm unit used for a microphone, which includes a resin cylindrical support member and a diaphragm. It is an object to enable tension to be applied to the vibrating membrane by a simple method so that the position of the vibrating membrane in the axial direction on the cylindrical support member does not change.

In order to achieve the above object, according to the present invention, a cylindrical support member made of a resin having an opening in at least one side in the axial direction, and a first end face that is an end face on the one side in the axial direction of the cylindrical support member. Opening of the first end surface of the cylindrical support member for a method of manufacturing a vibrating membrane unit used in a microphone, comprising a vibrating membrane fixed to cover the opening of the first end surface at an opening periphery. A fixing step in which the vibrating membrane is fixed to a peripheral portion, and a predetermined tension is applied to the vibrating membrane using the deformation of the cylindrical support member outward in the radial direction after the fixing step. And a tension applying step.

By the above method, in the fixing step, the vibrating membrane is fixed to the opening peripheral edge portion of the first end surface of the cylindrical support member, and then the cylindrical support member is deformed radially outward in the tension applying step. Thus, the vibrating membrane is pulled outward in the radial direction, and tension is applied. As a result, a grip margin for pulling the diaphragm is not necessary, and an operation for cutting the grip margin after the diaphragm is fixed becomes unnecessary. Unlike the method of applying tension to the vibrating membrane by pressing the vibrating membrane in the thickness direction, tension can be applied to the vibrating membrane so that the axial position of the vibrating membrane in the cylindrical support member does not change. it can.

In the method for manufacturing the diaphragm unit, the cylindrical support member has a plurality of grooves with a predetermined depth extending radially from the inner peripheral surface to the outer peripheral surface of the cylindrical support member. The first end surface side portion of the cylindrical support member is divided into a plurality of divided portions arranged in the circumferential direction by being formed at intervals in the direction, and the fixing step includes the cylindrical shape. The support member is formed so as to be integrated with the vibration film produced in advance, and the vibration film is fixed to the peripheral edge of the opening of the first end surface of the cylindrical support member. In the tension applying step, a predetermined tension is applied to the vibrating membrane by deformation of the cylindrical support member in the radial direction that occurs as the temperature of the cylindrical support member after molding decreases. It is preferable that it is a process to perform.

Thereby, in the fixing step, the cylindrical support member is integrated with the vibration film in the process of molding, and therefore, an adhesive for fixing the vibration film to the cylindrical support member becomes unnecessary. Here, when fixing the vibration film to the cylindrical support member with an adhesive, it is necessary to manage the amount of adhesive applied from the viewpoint of preventing the adhesive from protruding while maintaining the adhesive strength, The position of the vibrating membrane in the axial direction of the cylindrical support member changes due to the error in the amount of application. Therefore, in order to suppress this change as much as possible, it is necessary to strictly manage the amount of adhesive applied. However, if the cylindrical support member is integrated with the vibration film as described above, the vibration film can be firmly fixed to the cylindrical support member without using an adhesive. Therefore, management of the application amount of the adhesive is not necessary, and the axial position of the vibration film in the cylindrical support member is accurately determined.

The molded cylindrical support member is cooled from a high temperature immediately after molding to a normal temperature. Here, since the portion on the first end face side of the cylindrical support member is a plurality of divided portions that are divided in the circumferential direction by a plurality of grooves, each divided portion is formed in the cooling process of the cylindrical support member. Trying to deform radially outward. Therefore, a predetermined tension is applied to the vibration film by utilizing this deformation in the tension applying step. As described above, the divided portions of the cylindrical support member are deformed radially outward, whereby the vibrating membrane is pulled radially outward and a predetermined tension is applied to the vibrating membrane. The magnitude of the tension applied to the vibration film is determined by the amount of deformation of the portion constituting the first end face in each divided portion of the cylindrical support member. The amount of deformation is mainly determined by the thickness of each divided portion of the cylindrical support member, the number and depth of the grooves, and the resin material and molding conditions of the cylindrical support member. May be set in advance by experiments or the like so as to obtain the above. Therefore, an appropriate tension can be easily applied to the vibration film.

When the portion on the first end face side of the cylindrical support member is divided into a plurality of divided portions arranged in the circumferential direction, the cylindrical support member is arranged on the inner peripheral surface of each of the divided portions. It is preferable that the meat stealing part to be recessed is formed.

Thus, since the meat stealing portion is formed on the inner peripheral surface of each divided portion, each divided portion is more easily deformed more radially outward in the cooling process of the cylindrical support member. The amount of deformation of each divided portion can also be adjusted by the amount of depression on the inner peripheral surface by the meat stealing portion. Therefore, a predetermined tension can be more reliably and easily applied to the vibration film.

Alternatively, in the method for manufacturing the vibration membrane unit, the fixing step includes the cylindrical support member in a state where at least an end portion on the first end face side of the cylindrical support member is elastically deformed radially inward by pressing. The vibration film is fixed to the peripheral edge of the opening of the first end surface of the first end surface by welding or an adhesive, and the tension applying step releases the pressure and generates elasticity of the cylindrical support member. It is preferable that it is a step of applying a predetermined tension to the vibrating membrane by deformation outward in the radial direction by a restoring force.

Thereby, in the fixing step, particularly when the vibration film is fixed to the cylindrical support member by welding, the vibration film can be firmly fixed to the cylindrical support member without using an adhesive. At the time of fixing, at least the end portion on the first end face side of the cylindrical support member is in a state of being elastically deformed radially inward by pressing (that is, the diameter of the opening peripheral edge portion of the first end face is reduced). When the pressing is released, at least the end portion on the first end face side of the cylindrical support member tends to be deformed radially outward by the elastic restoring force (the diameter of the opening peripheral edge portion of the first end face is to be increased). . If the deformation to the outside in the radial direction due to the elastic restoring force of the cylindrical support member is used, the vibration film fixed to the cylindrical support member by welding or adhesive is pulled outward in the radial direction, and tension is applied. It will be. Therefore, in the tension application step, if the above-described pressure on the cylindrical support member is released, tension can be easily applied to the vibration film. The magnitude of the tension applied to the vibration film is determined by the amount of elastic deformation (the elastic restoring force outward in the radial direction) of the end portion on the first end surface side of the cylindrical support member, and this amount of elastic deformation. May be set in advance by experiments or the like so as to obtain the predetermined tension. Therefore, an appropriate tension can be easily applied to the vibration film.

Alternatively, in the method of manufacturing the diaphragm unit, the cylindrical support member is opened on both axial sides thereof, and the fixing step is performed on the opening peripheral edge of the first end surface of the cylindrical support member. The vibration film is a step of fixing by welding or an adhesive, and the tension applying step is such that the outer diameter is the cylindrical shape from the opening of the second end surface that is the end surface opposite to the first end surface of the cylindrical support member. A tension ring larger than the inner diameter of the support member is inserted into the cylindrical support member, and at least a first end face side end portion of the cylindrical support member is deformed radially outward by the tension ring, It is preferable that the step of applying a predetermined tension to the vibrating membrane by deformation.

Thereby, in the fixing step, particularly when the vibration film is fixed to the cylindrical support member by welding, the vibration film can be firmly fixed to the cylindrical support member without using an adhesive. Then, in the tension applying step, if the end portion on the first end face side of the cylindrical support member is deformed radially outward by the tension ring, the vibration film fixed to the cylindrical support member by welding or adhesive is radial. The tension is applied by pulling outward. The magnitude of the tension applied to the diaphragm is determined by the inner diameter of the cylindrical support member, the outer diameter of the tension ring, and the resin material, and these are set in advance by experiments to obtain an appropriate magnitude of tension. You just have to. Therefore, an appropriate tension can be easily applied to the vibration film.

The microphone includes the diaphragm unit, an LC oscillation circuit, a coil that constitutes the LC oscillation circuit, and a circuit that demodulates the oscillation wave, and the inductance of the coil changes as the diaphragm of the diaphragm unit vibrates. Thus, the semiconductor microphone is preferably configured such that the vibration film and the coil are held at a predetermined interval, and the change in the oscillation frequency of the LC oscillation circuit that changes due to the change in the inductance is demodulated.

In the case of such a semiconductor microphone, it is necessary to accurately maintain the distance between the diaphragm and the coil. However, according to the method for manufacturing the diaphragm unit of the present invention, the shaft of the diaphragm in the cylindrical support member is used. Since a predetermined tension can be applied to the vibration film so that the position in the direction does not change, the distance between the vibration film and the coil can be determined accurately, so that an acoustic signal can be detected with high accuracy.

In the case of the semiconductor microphone, the LC oscillation circuit including the coil and the circuit for demodulating the oscillation wave are semiconductors disposed on the second end face side which is the end face opposite to the first end face in the cylindrical support member. A plurality of input / output terminals for the semiconductor portion projecting from the semiconductor portion on the opposite side to the vibrating membrane, and the plurality of input / output terminals extending from a central axis of the cylindrical support member. It is preferable that these distances are arranged at different positions.

Thereby, in the main substrate to which the semiconductor microphone is attached, a plurality of conductive patterns to which a plurality of input / output terminals are respectively connected are formed concentrically so that the center of the cylindrical support member is the center of the conductive pattern. It is possible to connect each input / output terminal to each conductive pattern without aligning the cylindrical support member in the circumferential direction simply by attaching it to the main substrate so as to be positioned at the position.

In the method of manufacturing the semiconductor microphone using the vibrating membrane unit, the semiconductor portion is disposed on the second end surface side that is the end surface opposite to the first end surface of the cylindrical support member of the vibrating membrane unit. It fixes through a board | substrate or auxiliary resin, or directly.

As described above, according to the method for manufacturing the diaphragm unit of the present invention, the diaphragm is fixed to the opening peripheral edge of the first end surface of the cylindrical support member, and then the cylindrical support member is Since a predetermined tension is applied to the vibrating membrane by utilizing the outward deformation in the radial direction, vibration can be performed in a simple manner so that the axial position of the vibrating membrane in the cylindrical support member does not change. Tension can be applied to the membrane, and therefore a microphone capable of detecting an acoustic signal with high accuracy can be produced at low cost using the vibrating membrane unit produced according to the present invention.

It is sectional drawing which shows the semiconductor microphone provided with the diaphragm unit manufactured by the manufacturing method which concerns on Embodiment 1 of this invention. It is the figure which looked at the said semiconductor microphone from the diaphragm side. It is the schematic which shows the circuit structure in a semiconductor. It is a circuit diagram which shows the Hartley type | mold oscillation circuit which is an example of LC oscillation circuit. It is the figure which looked at the cylindrical support member from the 1st end surface side. It is a side view of a cylindrical support member. It is the schematic which shows the relationship between the magnetic flux which generate | occur | produces when the resonance current flows into the coil part of LC oscillation circuit, and the magnetic permeability material part of a diaphragm. It is a figure which shows the conductive pattern formed on the main board | substrate with which a semiconductor microphone is attached. In Embodiment 2, it is sectional drawing which shows the state which fitted the cylindrical support member inside the annular jig. It is the figure which looked at the cylindrical support member fitted inside the said annular jig from the 1st end surface side. In Embodiment 3, it is a figure which shows the state which fitted the tension ring in the ditch | groove part of the cylindrical support member. FIG. 6 is a cross-sectional view showing a semiconductor microphone according to a fourth embodiment. FIG. 10 is a cross-sectional view illustrating a semiconductor microphone according to a fifth embodiment. FIG. 10 is a cross-sectional view showing a semiconductor microphone according to a sixth embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
1 and 2 show a semiconductor microphone M including a diaphragm unit 1 manufactured by the manufacturing method according to Embodiment 1 of the present invention. The semiconductor microphone M includes a diaphragm unit 1, a substrate 2, a semiconductor unit 3 mounted on the substrate 2, and a plurality of input / output terminals 4 (two power supply terminals in the present embodiment). And one output signal terminal).

The vibrating membrane unit 1 includes a resin-made cylindrical support member 11 that is open on both sides in the axial direction, and a first end surface that is an end surface on one side (upper side in FIG. 1) of the cylindrical support member 11 in the axial direction. The concave portion 13 formed at the peripheral edge of the opening 12 is provided with a vibration film 21 fixed so as to cover the opening of the first end face 12. The vibrating membrane 21 is a permeable (or conductive) vibrating membrane that vibrates in response to an acoustic signal (sound pressure). An outer peripheral edge portion of a base material 22 described later in the vibration film 21 is fixed to the concave portion 13 of the first end surface 12 of the cylindrical support member 11. The depth of the recess 13 is substantially the same as the thickness of the base material 22. The resin constituting the cylindrical support member 11 may be any resin as long as a predetermined tension can be applied to the vibration film 21 as will be described later. In the present embodiment, the cylindrical support member 11 has a cylindrical shape, and the vibration film 21 has a circular shape correspondingly, but is not limited to this shape.

A concave portion 15 is formed on the peripheral edge of the opening of the second end surface 14 which is the end surface opposite to the first end surface 12 of the cylindrical support member 11 (the lower side in FIG. 1). The substrate 2 is fitted and fixed by press-fitting. The substrate 2 covers the opening of the second end face 14. Further, the depth of the recess 15 is substantially the same as the thickness of the substrate 2. The substrate 2 may be fixed to the recess 15 by adhesion, or may be fixed by both press-fitting and adhesion. However, since it is necessary to manage the coating amount of the adhesive, it is preferable not to use it as much as possible.

The semiconductor portion 3 is disposed on the second end face 14 side of the cylindrical support member 11. That is, the semiconductor portion 3 is mounted on the surface (the upper surface in FIG. 1) of the substrate 2 that is fixed to the concave portion 15 of the second end surface 14 of the cylindrical support member 11. The distance between the semiconductor part 3 and the vibration film 21 (specifically, the distance between a coil part 32 described later and the magnetically permeable material part 23 of the vibration film 21) is maintained at a predetermined distance. The center of the semiconductor part 3 substantially coincides with the central axis of the cylindrical support member 11.

The plurality of (three) input / output terminals 4 are provided so as to protrude from the semiconductor portion 3 to the side opposite to the vibrating membrane 21. In the present embodiment, each input / output terminal 4 is supported by a through hole 2a penetrating in the thickness direction of the substrate 2 and its front end surface is a surface opposite to the vibrating membrane 21 in the substrate 2 (in FIG. 1). Facing the bottom surface. These input / output terminals 4 are respectively arranged at different positions from the central axis of the cylindrical support member 11 (which is also the central axis of the substrate 2 and the central axis of the semiconductor microphone M). On the other hand, a plurality (three) of conductive patterns 26 to which the plurality of input / output terminals 4 are respectively connected are formed on the main substrate 25 (see FIG. 8) to which the semiconductor microphone M is attached. The plurality of conductive patterns 26 are formed concentrically on the main substrate 25, and the diameter of each conductive pattern 26 is set to be the same as the distance from the central axis of each input / output terminal 4. As a result, the cylindrical support member 11 is attached to the main substrate 25 so that the center thereof is located at the center of the conductive pattern 26, and each input / output is performed without aligning the cylindrical support member 11 in the circumferential direction. The terminal 4 can be connected to each conductive pattern 26. Further, by projecting the plurality of input / output terminals 4 from the semiconductor portion 3 to the opposite side of the vibration film 21 and connecting the input / output terminals 4 to the main substrate 25, the semiconductor microphone M can be reduced in size as compared with wiring by wire bonding. . The plurality of input / output terminals 4 may be located anywhere in the circumferential direction of the cylindrical support member 11 as long as the distance from the central axis of the cylindrical support member 11 is different from each other. .

As shown in FIG. 3, the semiconductor unit 3 includes a coil unit 32 and a capacitor 33, and an LC oscillation circuit 31 whose oscillation frequency is determined by the coil unit 32 and the capacitor 33, and an electrical audio signal from the oscillation wave. An FM demodulating circuit 37 configured to extract and output the extracted electrical audio signal as an analog output signal via the output signal terminal of the plurality of input / output terminals 4 is configured. The semiconductor part 3 is formed by sealing these circuits with a resin. When a digital output signal is required, as shown by a two-dot chain line in FIG. 3, the analog output signal is modulated by a modulation reference input signal supplied to the semiconductor unit 3 from the outside and output as a digital output signal. A modulation circuit 38 to be used may be added. In this case, an input signal terminal for a modulation reference input signal is added as the input / output terminal 4, and when outputting a digital output signal in addition to an analog output signal, an output signal terminal for a digital output signal is added. Will be.

The LC oscillation circuit 31 may be a variety of oscillation circuits such as a Hartley type, a Colpitts type, a base tuning type, and a collector tuning type. Here, the Hartley type oscillation circuit shown in FIG. 4 will be described as an example.

The LC oscillation circuit 31 includes a coil portion 32 and a capacitor 33 having an inductance value and a capacitance value, respectively, such that the oscillation frequency is about 100 MHz to several hundred MHz. Here, in FIG. 4, the coil part 32 is comprised by the 1st coil 32a and the 2nd coil 32b.

The transistor 34 used in the LC oscillation circuit 31 is also configured in the semiconductor unit 3 together with the coil unit 32 and the capacitor 33. The capacitance value of the capacitor 33 is fixed. The power source is usually disposed between point A (+ side) and point B (− side) in FIG.

The distance between the first coil 32a and the vibration film 21 (specifically, the magnetically permeable material part 23) of the coil part 32 and the distance between the second coil 32b and the vibration film 21 (the magnetically permeable material part 23) are the same. Thus, the predetermined interval is maintained. This predetermined interval is within a distance (for example, 0.1 mm or more and 0.5 mm or less) that the magnetic flux 41 (see FIG. 7) generated when the resonance current flows through the coil unit 32 by the oscillation of the LC oscillation circuit 31 is reached. ).

The vibration film 21 includes a base material 22 and a magnetically permeable material portion 23 provided on the surface of the base material 22 on the semiconductor unit 3 side (the lower surface in FIG. 1) by sputtering. The substrate 22 is a flat thin film having a thickness of several μm to several tens of μm, has an area of about 10 mm ^{2 to} about 100 mm ² , and 30 in an atmosphere of about 250 ° C. to 300 ° C. It is preferable to use a film material (for example, a polyimide film) having a heat resistance property that only causes deformation within a range that does not hinder practical use even if left for about 60 seconds or more for about 2 seconds or less. The magnetically permeable material portion 23 may be provided in a portion of the base material 22 facing the semiconductor portion 3 (coil portion 32) or a central portion of the base material 22 where bending due to vibration of the vibration film 21 hardly occurs. preferable. In the present embodiment, the magnetically permeable material portion 23 is provided in the central portion of the base material 22, which is a portion facing the semiconductor portion 3 (coil portion 32) in the base material 22 (the center of the magnetic permeable material portion 23 and the semiconductor). The center of the portion 3 substantially coincides with the central axis of the cylindrical support member 11).

The magnetically permeable material portion 23 has a thickness of several μm to several tens of μm and is made of a magnetically permeable material (for example, a ferrite material or a permalloy material) having a permeability much higher than air in the oscillation frequency band. Become.

As shown in FIGS. 5 and 6, the first end surface 12 of the cylindrical support member 11 has a plurality of grooves having a predetermined depth extending in the radial direction from the inner peripheral surface to the outer peripheral surface of the cylindrical support member 11. 16 are formed at intervals in the circumferential direction. With the formation of these groove portions 16, the portion on the first end face 12 side of the cylindrical support member 11 is divided into a plurality (the same number as the groove portions 16) of divided portions 17 arranged in the circumferential direction. It is preferable that a meat stealing portion 18 for recessing the inner peripheral surface is formed on the inner peripheral surface of each divided portion 17 as in the present embodiment. In the present embodiment, the meat stealing portion 18 of each divided portion 17 has a semicircular cross section and extends in the axial direction of the cylindrical support member 11. Each meat stealing portion 18 is formed in order to easily deform (easily warp) each divided portion 17 radially outward in a cooling process after molding of the cylindrical support member 11 described later. As long as it is possible to easily deform each divided portion 17 radially outward, the inner peripheral surface of each divided portion 17 may be recessed in any shape. Note that the meat stealing portion 18 is not always necessary, and even if the meat stealing portion 18 is not provided, each divided portion 17 is usually deformed radially outward in the cooling process after the cylindrical support member 11 is molded.

The thickness of each divided portion 17 in the cylindrical support member 11, the number and depth of the groove portions 16, and the amount of depression of the inner peripheral surface by the meat stealing portion 18 are determined in the cooling process after the cylindrical support member 11 is molded. It is determined together with the resin material of the cylindrical support member 11 and the molding conditions so that a predetermined tension is applied to the vibration film 21. The predetermined tension is a value that can faithfully convert a change in sound pressure into an electric signal, and is a value such that the maximum amplitude of the vibrating membrane 21 is several μm. The number of groove portions 16 (that is, the number of divided portions 17) is preferably about 8 to 16, and when the meat stealing portions 18 are formed in each divided portion 17 as in the present embodiment, the number of groove portions 16 depends on the meat stealing portions 18 in each divided portion 17. The amount of depression on the inner peripheral surface is preferably more than 0 and not more than half of the thickness of the divided portion 17. It is preferable that the width of the groove portion 16 (the interval between the adjacent divided portions 17) is as small as possible so that the groove portion 16 can be formed by molding. In this way, a predetermined tension is applied to the vibration film 21 so that a change in sound pressure can be faithfully converted into an electric signal.

The sound detection of the semiconductor microphone M utilizes the fact that the distance between the vibration film 21 and the semiconductor unit 3 is changed by the vibration of the vibration film 21 due to an acoustic signal (sound pressure) input to the vibration film 21.

The sound detection operation will be described with reference to FIG. When the LC oscillation circuit 31 oscillates, a resonance current flows through the coil portion 32 and a magnetic flux 41 is generated. However, since the magnetically permeable material portion 23 is disposed within the reach distance of the magnetic flux 41, a part of the magnetic flux 41 is generated. Will pass through the magnetically permeable material portion 23.

When part of the magnetic flux 41 passes through the magnetically permeable material part 23, the inductance of the coil part 32 increases, and the oscillation frequency of the LC oscillation circuit 31 becomes lower than when the magnetically permeable material part 23 is not disposed. When the vibrating membrane 21 comes closer to the coil portion 32 than the fixed position when there is no sound, that is, when the distance between the vibrating membrane 21 and the coil portion 32 becomes smaller, the inside of the magnetically permeable material portion 23 As a result, the inductance of the coil portion 32 is increased and the oscillation frequency of the LC oscillation circuit 31 is further lowered as compared with the case where the vibrating membrane 21 is in a fixed position. On the other hand, when the vibrating membrane 21 is further away from the coil portion 32 than the fixed position, that is, when the distance between the vibrating membrane 21 and the coil portion 32 is increased, the magnetic flux passing through the magnetically permeable material portion 23. As a result, the inductance of the coil portion 32 is reduced and the oscillation frequency of the LC oscillation circuit 31 is increased as compared with the case where the vibrating membrane 21 is in a fixed position.

Instead of the magnetically permeable material portion 23, it is also possible to provide a conductive material portion made of a conductive material (for example, copper or the like) having a sufficiently low electric resistance in the oscillation frequency band. In this case, when a part of the magnetic flux 41 reaches the conductive material part, an eddy current is generated in the conductive material part and a part of the magnetic flux 41 is consumed, thereby reducing the inductance of the coil part 32. The oscillation frequency of the LC oscillation circuit 31 is higher than when no conductive material portion is disposed. When the vibrating membrane 21 comes closer to the coil portion 32 than the fixed position when there is no sound, the magnetic flux 41 that reaches the conductive material portion increases, and thereby the vortex generated in the conductive material portion. As the current increases, the consumption of the magnetic flux 41 increases. As a result, the inductance of the coil section 32 decreases, and the oscillation frequency of the LC oscillation circuit 31 becomes higher. On the other hand, when the vibrating membrane 21 is further away from the coil portion 32 than the fixed position, the magnetic flux 41 passing through the conductive material portion is reduced, thereby reducing the eddy current generated in the conductive material portion, As a result, the consumption of the magnetic flux 41 is reduced, and as a result, the inductance of the coil section 32 is increased and the oscillation frequency of the LC oscillation circuit 31 is lowered.

As the magnetically permeable material, it is effective to select a material having as high an electrical resistance as possible from the viewpoint of preventing the influence of eddy current generated in the conductive material portion. In addition, if the magnetic permeable material portion 23 is too thin and magnetic saturation occurs, the change in inductance accompanying the change in the distance between the vibration film 21 and the coil portion 32 becomes small. It is preferable to use a material having a high saturation magnetic flux density and a thickness that does not cause the occurrence of magnetic field.

As the conductive material, it is effective to select a material having the smallest possible magnetic permeability because the high magnetic permeability lowers the oscillation frequency and inhibits the frequency increase due to the eddy current generated in the conductive material portion. . The thickness of the conductive material portion may be several μm to several tens of μm as in the case of the magnetically permeable material portion 23, but it is necessary to make the thickness such that an eddy current of about 100 MHz to about several 100 MHz flows. is there. When the conductive material is copper, the depth at which the high frequency current of 100 MHz flows is about 7 μm, and the depth at which the high frequency current of 500 MHz flows is about 3 μm, so the minimum value of the thickness of the conductive material portion is It is about 7 μm.

Next, a method for manufacturing the diaphragm unit 1 used in the semiconductor microphone M as described above will be described.

First, a film (for example, an imide film) to be the base material 22 of the vibration film 21 is prepared. This film has an area larger than the area predetermined as the vibration film 21. Then, a magnetically permeable material is sputtered on the entire film, and then unnecessary portions of the sputtered permeable material are removed by etching (dry etching or wet etching), thereby forming the permeable material portion 23. . Subsequently, by cutting the film into a predetermined area, the vibration film 21 including the base material 22 and the magnetically permeable material portion 23 provided at the approximate center of the base material 22 is completed. In addition, what is necessary is just to carry out similarly to the case where the magnetic permeability material part 23 is provided also when providing a conductive material part in the approximate center of the base material 22.

Note that the method of forming the magnetically permeable material portion 23 (or the conductive material portion) on the base material 22 is not limited to sputtering and etching, and a magnetically permeable material (or conductive material) is applied or a magnetically permeable material ( Alternatively, a sheet made of a conductive material) may be attached.

Next, the vibrating membrane 21 is fixed to the concave portion 13 of the first end surface 12 of the cylindrical supporting member 11 by molding the cylindrical supporting member 11 so as to be integrated with the produced vibrating membrane 21. To. That is, the cavity is filled with a molten resin in a state where the vibration film 21 thus prepared is set in a portion corresponding to the first end face 12 in the cavity of the mold for molding the cylindrical support member 11. The support member 11 is molded (injection molding). At the time of molding, the molten resin enters a minute concave portion on the surface of the base material 22 of the vibration film 21 that has become rough due to etching, so that the concave portion 13 of the first end surface 12 of the cylindrical support member 11 is vibrated after molding. The film 21 is firmly fixed.

After the molten resin is solidified, the molded cylindrical support member 11 (the cylindrical support member 11 integrated with the vibration film 21) is taken out from the mold. The temperature of the cylindrical support member 11 immediately after being taken out from the mold is considerably higher than room temperature (for example, about 200 ° C.).

And the temperature of the cylindrical support member 11 decreases from high temperature to room temperature by natural cooling. Along with this temperature decrease, each divided portion 17 of the cylindrical support member 11 tends to be deformed radially outward by the meat stealing portion 18 formed on the inner peripheral surface thereof. The amount of deformation of each divided portion 17 outward in the radial direction is larger toward the first end surface 12 side, and the amount of deformation of the portion constituting the first end surface 12 in each divided portion 17 of the cylindrical support member 11 outward in the radial direction is increased. Is the largest. The amount of deformation of the portion constituting the first end face 12 in each divided portion 17 (the portion to which the vibration film 21 is fixed) radially outward is mainly the thickness of each divided portion 17 in the cylindrical support member 11, The number and depth of the groove portions 16, the amount of recess in the inner peripheral surface by the meat stealing portion 18, and the resin material and molding conditions of the cylindrical support member 11 are determined, and these are given the predetermined tension to the vibration film 21. Therefore, when the temperature of the cylindrical support member 11 reaches room temperature, the predetermined tension is applied to the vibrating membrane 21. In this way, the diaphragm unit 1 including the diaphragm 21 to which a predetermined tension is applied is completed.

In order to manufacture the semiconductor microphone M using the diaphragm unit 1 manufactured as described above, the semiconductor unit 3 is placed on the second end face 14 side of the cylindrical support member 11 of the diaphragm unit 1 with the substrate 2 interposed therebetween. And fix. Specifically, the substrate 2 on which the semiconductor unit 3 is mounted in advance is fitted and fixed in the recess 15 of the second end surface 14 of the cylindrical support member 11 in the diaphragm unit 1 by press fitting. When the substrate 2 is fixed to the recess 15 by bonding, the substrate 2 is fitted into the recess 15 after applying a predetermined amount of adhesive to the recess 15. Thus, the semiconductor microphone M is completed.

When the semiconductor microphone M is attached to the main substrate 25, the cylindrical support member 11 of the semiconductor microphone M may be positioned at the center of the conductive pattern 26 on the main substrate 25. For this purpose, for example, a positioning hole may be formed at the center position of the conductive pattern 26 in the main substrate 25 and a positioning pin that fits into the positioning hole may be provided on the substrate 2.

Therefore, in this embodiment, the cylindrical support member 11 is molded so as to be integrated with the vibration film 21 produced in advance, so that the vibration film 21 is formed in the concave portion 13 of the first end surface 12 of the cylindrical support member 11. Is fixed, and then the diaphragm 21 is deformed outwardly in the radial direction of the divided portions 17 in the cylindrical support member 11 which occurs as the temperature of the cylindrical support member 11 after the molding decreases. Since the vibrating membrane unit 1 is manufactured so as to apply a predetermined tension, the predetermined tension can be easily applied to the vibrating membrane 21 by using the deformation of each divided portion 17 outward in the radial direction. At the same time, unlike the method of applying tension to the vibrating membrane 21 by pressing the vibrating membrane 21 in the thickness direction, the vibrating membrane 21 is attached to the vibrating membrane 21 so that the position of the vibrating membrane 21 in the axial direction on the cylindrical support member 11 does not change. Deployment can be imparted. As a result, the diaphragm unit 1 manufactured as described above can be suitably used for the semiconductor microphone M in which the distance between the semiconductor unit 3 and the diaphragm 21 is important for acoustic detection.

Further, since the cylindrical support member 11 is integrated with the vibration film 21 in the process of molding, an adhesive for fixing the vibration film 21 to the cylindrical support member 11 is not necessary. Thereby, the vibration film 21 can be firmly fixed to the cylindrical support member 11 without using an adhesive, and management of the application amount of the adhesive becomes unnecessary. In addition, since no adhesive is present, the position of the vibrating membrane 21 in the axial direction of the cylindrical support member 11 is determined more accurately. From this point also, the vibrating membrane unit 1 manufactured as described above is a semiconductor microphone. It can be suitably used for M. Therefore, the semiconductor microphone M that can accurately detect the acoustic signal can be manufactured at low cost.

(Embodiment 2)
In the present embodiment, the manufacturing method of the diaphragm unit 1 is different from that of the first embodiment. In this connection, in the present embodiment, the meat stealing portion 18 as in the first embodiment is not formed on the inner peripheral surface of each divided portion 17 of the cylindrical support member 11. Other configurations are the same as those of the first embodiment.

A method for manufacturing the diaphragm unit 1 of the present embodiment will be described.

The vibrating membrane 21 is produced in the same manner as in the first embodiment. In addition, the cylindrical support member 11 is molded separately from the production of the vibration film 21. In the present embodiment, the cylindrical support member 11 is not limited to molding, and can be manufactured by cutting, for example. However, molding is advantageous in that many cylindrical support members 11 can be manufactured at low cost.

Subsequently, as shown in FIGS. 9 and 10, the cylindrical support member 11 is fitted into the annular jig 51. The inner peripheral surface of the annular jig has an inner diameter that is substantially the same as the outer diameter of the cylindrical support member 11 (an inner diameter that is slightly larger than the outer diameter of the cylindrical support member 11), and in the axial direction of the annular jig 51. A straight portion 51a having a constant inner diameter, and a tapered portion 51b that is continuously located on one side in the axial direction of the annular jig 51 with respect to the straight portion 51a and whose diameter decreases toward the opposite side of the straight portion 51a. And have. The tapered portion 51b is configured to uniformly press all the divided portions 17 of the cylindrical support member 11 radially inward when the entire cylindrical support member 11 is fitted inside the annular jig 51.

The cylindrical support member 11 is inserted into the annular jig 51 from the opening on the straight portion 51a side of the annular jig 51 with the first end face 12 side being the front side, and finally the cylindrical support member. 11 is fitted inside the annular jig 51. Thereby, each division part 17 of the cylindrical support member 11 is pressed radially inward by the taper part 51b, and is in a state of being elastically deformed radially inward.

Next, in the state of elastic deformation, the produced vibration membrane 21 is fixed to the recess 13 of the first end face 12 of the produced cylindrical support member 11 by welding. By this welding, the vibration film 21 is firmly fixed to the recess 13 of the first end surface 12 of the cylindrical support member 11.

Next, the cylindrical support member 11 to which the vibration film 21 is fixed is removed from the annular jig 51, and the pressure on the radially inner side of each divided portion 17 is released. By this release, each divided portion 17 tries to deform outward (in an attempt to return to its original state) by its elastic restoring force. A predetermined tension is applied to the vibrating membrane 21 by the deformation of each divided portion 17 outward in the radial direction by the elastic restoring force. Thus, the diaphragm unit 1 is completed.

In the present embodiment, the magnitude of the tension applied to the vibrating membrane 21 is the amount of elastic deformation inward in the radial direction of the portion constituting the first end face 12 in each divided portion 17 (elastic restoring force outward in the radial direction). The amount of elastic deformation (which varies depending on the thickness of each divided portion 17, the number and depth of the groove portions, and the resin material) can be set in advance by experiments or the like so as to obtain the predetermined tension. That's fine.

In addition, as long as at least the end portion on the first end face 12 side of the cylindrical support member 11 can be elastically deformed radially inward so as to obtain an elastic restoring force capable of applying the predetermined tension, The groove part 16 (dividing part 17) may not be present. However, since the groove portion 16 also has a role of preventing the vibration characteristics of the vibration film 21 from deteriorating by communicating the inside and the outside of the cylindrical support member 11, when the groove portion 16 is eliminated, The tubular support member 11 is preferably provided with a communication hole that communicates the inside and the outside.

In addition to the annular jig 51 as described above, any jig can be used as long as it can press at least the end portion on the first end face side of the cylindrical support member 11 and release the press. Also good.

The method of manufacturing the semiconductor microphone M using the manufactured diaphragm unit 1 is the same as that of the first embodiment.

Therefore, in the present embodiment, the cylindrical support is performed with the annular jig 51 pressing each divided portion 17 of the cylindrical support member 11 radially inward to elastically deform each divided portion 17 radially inward. The vibration film 21 is fixed to the concave portion 13 of the first end surface 12 of the member 11 by welding, and then the pressure is released, and the elastic restoring force of each divided portion 17 of the cylindrical support member 11 generated by the release. Since the diaphragm unit 1 is manufactured so as to apply a predetermined tension to the diaphragm 21 by deformation to the outside in the radial direction, as in the first embodiment, radially outward of each divided portion 17. By utilizing this deformation, a predetermined tension can be easily applied to the vibration film 21 and tension is applied to the vibration film 21 so that the axial position of the vibration film 21 in the cylindrical support member 11 does not change. With It can be. Further, since the vibration film 21 is fixed to the cylindrical support member 11 by welding, an adhesive is not necessary, and the axial position of the vibration film 21 in the tubular support member 11 is determined more accurately. And the semiconductor microphone M which can detect an acoustic signal accurately can be manufactured cheaply using the vibration membrane unit 1 manufactured in this way.

In this embodiment, the vibration film 21 is fixed to the cylindrical support member 11 by welding. However, the vibration film 21 may be fixed to the cylindrical support member 11 with an adhesive. In this case, it is necessary to manage the application amount of the adhesive, but compared with the method of applying tension to the vibration film 21 by pressing the vibration film 21 in the thickness direction, the vibration film 21 in the cylindrical support member 11 is controlled. The axial position is determined accurately.

(Embodiment 3)
In the present embodiment, the manufacturing method of the diaphragm unit 1 is different from those of the first and second embodiments. In this regard, in the present embodiment, the meat stealing portion 18 as in the first embodiment is not formed on the inner peripheral surface of each divided portion 17 of the cylindrical support member 11, but is shown in FIG. 11. As described above, the recessed groove portion 19 into which a tension ring 55 described later is fitted is formed so as to extend in the circumferential direction of the cylindrical support member 11. The concave groove portion 19 of each divided portion 17 is arranged at the same position in the axial direction of the cylindrical support member 11 (the end portion on the first end surface 12 side on the inner peripheral surface of the cylindrical support member 11). It is formed to be continuous in the direction (however, it is interrupted at the groove 16). Other configurations are the same as those of the first embodiment.

A method for manufacturing the diaphragm unit 1 of the present embodiment will be described.

In the same manner as in the second embodiment, the vibrating membrane 21 and the cylindrical support member 11 are separately manufactured. Also in this embodiment, similarly to the second embodiment, the cylindrical support member 11 is not limited to molding, and can be manufactured by, for example, cutting.

Subsequently, the produced vibration membrane 21 is fixed to the recess 13 of the first end surface 12 of the produced cylindrical support member 11 by welding. At the time of this welding, each divided portion 17 of the cylindrical support member 11 is prevented from being deformed in the radial direction. By this welding, the vibration film 21 is firmly fixed to the recess 13 of the first end surface 12 of the cylindrical support member 11.

Next, the tension ring 55 is inserted from the opening of the second end face 14 of the cylindrical support member 11. The outer diameter of the tension ring 55 is larger than the inner diameter of the cylindrical support member 11 including the concave groove portion 19. In the present embodiment, the tension ring 55 has a substantially C shape with a part in the circumferential direction cut off, and thus the tension ring 55 is contracted to be smaller than the inner diameter of the cylindrical support member 11. The tension ring 55 can be easily inserted into the cylindrical support member 11. Then, the tension ring 55 is inserted into the cylindrical support member 11 with the diameter reduced, and the tension ring 55 is fitted into the concave groove portion 19. Then, since the tension ring 55 tries to expand its diameter by its elastic restoring force, the end portion on the first end face 12 side of the cylindrical support member 11 is deformed radially outward by the tension ring 55. Due to this deformation, a predetermined tension is applied to the vibration film 21. Thus, the diaphragm unit 1 is completed.

In the present embodiment, the magnitude of the tension applied to the vibration film 21 is determined by the inner diameter of the concave groove portion 19 in the cylindrical support member 11, the outer diameter of the tension ring 55, and the resin material. It may be set in advance by experiments or the like so as to obtain the tension.

The concave groove portion 19 is not necessarily required. If the concave groove portion 19 is not provided, the amount of diameter reduction of the tension ring 55 may be small. As a result, even if the tension ring 55 is a complete ring shape, the cylindrical support member 11 can be inserted. On the other hand, by providing the recessed groove portion 19, it is possible to prevent the tension ring 55 from being displaced in the axial direction of the cylindrical support member 11, and it is possible to prevent a change in the tension of the vibration film 21 due to this deviation.

Further, not limited to the tension ring 55 as described above, any member can be used as long as at least the end portion on the first end face 12 side of the cylindrical support member 11 can be deformed radially outward. May be.

The method of manufacturing the semiconductor microphone M using the manufactured diaphragm unit 1 is the same as that of the first embodiment.

Therefore, in this embodiment, the diaphragm 21 is fixed to the recess 13 of the first end surface 12 of the cylindrical support member 11 by welding, and then the outer diameter is from the opening of the second end surface 14 of the cylindrical support member 11. A tension ring 55 larger than the inner diameter of the cylindrical support member 11 (including the concave groove portion 19) is inserted into the cylindrical support member 11, and the first end surface 12 of the cylindrical support member 11 is inserted by the tension ring 55. Since the vibrating membrane unit 1 is manufactured by deforming the end portion on the side radially outward and applying a predetermined tension to the vibrating membrane 21 by the deformation, the same as in the first and second embodiments. A predetermined tension can be easily applied to the vibrating membrane 21 by utilizing the deformation of each divided portion 17 in the radial direction, and the axial position of the vibrating membrane 21 in the cylindrical support member 11 is determined. Change It is possible to impart tension to the oddly vibrating membrane 21. Further, since the vibration film 21 is fixed to the cylindrical support member 11 by welding, an adhesive is not necessary, and the axial position of the vibration film 21 in the tubular support member 11 is determined more accurately. And the semiconductor microphone M which can detect an acoustic signal accurately can be manufactured cheaply using the vibration membrane unit 1 manufactured in this way.

In the present embodiment, the vibration film 21 is fixed to the cylindrical support member 11 by welding. However, as described in the second embodiment, the vibration film 21 may be fixed to the cylindrical support member 11 with an adhesive. Good.

(Embodiment 4)
As shown in FIG. 12, in this embodiment, the semiconductor part 3 is directly fixed to the second end face 14 side of the cylindrical support member 11 without the substrate 2 interposed therebetween. The substrate 2 does not exist, and the input / output terminal 4 is supported by the sealing resin of the semiconductor unit 3. Further, the shape of the cylindrical support member 11 on the second end face 14 side is different from that of the second embodiment. Other configurations are the same as those of the second embodiment.

That is, in the present embodiment, the end portion on the second end surface 14 side of the inner peripheral surface of the cylindrical support member 11 of the vibration membrane unit 1 protrudes inward, and the area of the opening of the second end surface 14 is the first end surface. It is smaller than the area of 12 openings. A recess 61 is formed in the opening peripheral edge of the second end face 14, and the semiconductor part 3 is fixed in the recess 61 to cover the opening of the second end face 14. The depth of the recess 61 is substantially the same as the thickness of the semiconductor portion 3. The semiconductor part 3 is fixed by press-fitting the semiconductor part 3 into the recess 61, but may be fixed by bonding or fixed by both press-fitting and bonding.

The manufacturing method of the diaphragm unit 1 of the present embodiment is the same as that of the second embodiment. In addition, since the area of the opening of the 2nd end surface 14 of the cylindrical support member 11 is smaller than the area of the opening of the 1st end surface 12, the method of the said Embodiment 1 and 3 is not practical.

To manufacture the semiconductor microphone M using the completed diaphragm unit 1, the semiconductor unit 3 is directly fixed to the second end face 14 side of the tubular support member 11 of the diaphragm unit 1. Specifically, the semiconductor portion 3 is fitted and fixed in the recess 61 of the second end surface 14 of the cylindrical support member 11 in the vibration membrane unit 1 by press-fitting. In addition, when fixing the semiconductor part 3 to the recessed part 61 by adhesion | attachment, after apply | coating the predetermined amount of adhesives to the recessed part 61, the semiconductor part 3 is engage | inserted in the recessed part 61. FIG. In this way, the semiconductor microphone M that can accurately detect the acoustic signal can be manufactured at low cost.

(Embodiment 5)
As shown in FIG. 13, also in the present embodiment, the semiconductor unit 3 is directly fixed to the second end face 14 side of the cylindrical support member 11 without using the substrate 2 as in the fourth embodiment. It is a thing. However, the shape of the cylindrical support member 11 on the second end face 14 side is different from that of the fourth embodiment. Other configurations are the same as those in the fourth embodiment.

That is, in the present embodiment, the cylindrical support member 11 of the diaphragm unit 1 has a bottomed cylindrical shape in which only the first end face 12 side is open. A recess 62 is formed at the center of the second end surface 14 where no opening exists in the cylindrical support member 11, and the semiconductor portion 3 is fixed in the recess 62. The depth of the recess 62 is substantially the same as the thickness of the semiconductor portion 3. The semiconductor part 3 is fixed by press-fitting the semiconductor part 3 into the recess 62, but may be fixed by adhesion or by both press-fitting and adhesion.

The manufacturing method of the diaphragm unit 1 of the present embodiment is the same as that of the second embodiment. In addition, since there is no opening in the 2nd end surface 14, it is impossible to perform the method of the said Embodiment 1 and 3. FIG.

To manufacture the semiconductor microphone M using the completed diaphragm unit 1, the semiconductor unit 3 is directly fixed to the second end face 14 side of the tubular support member 11 of the diaphragm unit 1. This fixing method is the same as that in the fourth embodiment. In this way, the semiconductor microphone M that can accurately detect the acoustic signal can be manufactured at low cost.

(Embodiment 6)
As shown in FIG. 14, in the present embodiment, the semiconductor unit 3 is fixed to the second end surface 14 side of the cylindrical support member 11 via the auxiliary resin 65 instead of the substrate 2 of the first embodiment. It is a thing. Also in this embodiment, the input / output terminal 4 is supported by the sealing resin of the semiconductor unit 3 as in the fourth embodiment. Other configurations are the same as those of the first embodiment (however, no recess is formed in the opening peripheral edge of the second end surface 14 of the cylindrical support member 11).

In other words, in the present embodiment, the auxiliary resin 65 has a ring shape having a through hole 66 penetrating in the thickness direction of the auxiliary resin 65 in the center thereof, and is a cylindrical support that has the same shape as in the first embodiment. The member 11 is fixed by being press-fitted into the opening of the second end surface 14 of the member 11. Note that the auxiliary resin 65 may be fixed by press-fitting into a recessed portion formed in the opening peripheral edge portion of the second end surface 14 of the cylindrical support member 11, similarly to the substrate 2 of the first embodiment. Further, instead of press-fitting, the auxiliary resin 65 may be fixed to the cylindrical support member 11 by bonding, or by both press-fitting and bonding.

A concave portion 67 is formed in the opening peripheral edge portion of the through-hole 66 on the surface on one side in the thickness direction of the auxiliary resin 65 (the surface on the side opposite to the vibration film 21 when fixed to the cylindrical support member 11). The semiconductor portion 3 is fixed in the recess 67 by press-fitting (or bonding, or both press-fitting and bonding), and covers the opening of the through-hole 66. The auxiliary resin 65 may be the same material as the cylindrical support member 11 or a different material.

The manufacturing method of the diaphragm unit 1 of the present embodiment is the same as that of the first embodiment. The diaphragm support unit 11 may be manufactured in the same manner as in the second or third embodiment, with the cylindrical support member 11 having the same shape as in the second or third embodiment. That is, before the auxiliary resin 65 is fixed, the area of the opening of the second end face 14 is the same as the area of the opening of the first end face 12, and therefore, unlike the fourth and fifth embodiments, only the method of the second embodiment. In addition, the methods of Embodiments 1 and 3 can be performed, and the degree of freedom in manufacturing the diaphragm unit 1 is increased.

To manufacture the semiconductor microphone M using the completed diaphragm unit 1, the semiconductor unit 3 is fixed to the second end face 14 side of the tubular support member 11 of the diaphragm unit 1 with an auxiliary resin 65. Specifically, the auxiliary resin 65 is produced separately from the manufacture of the diaphragm unit 1. The auxiliary resin 65 is preferably produced by molding, but can also be produced by cutting. Subsequently, the semiconductor part 3 is fixed to the concave part 67 of the auxiliary resin 65 by press-fitting. Thereafter, the auxiliary resin 65 to which the semiconductor portion 3 is fixed is fixed to the opening of the second end surface 14 of the cylindrical support member 11 by press fitting. In this way, the semiconductor microphone M that can accurately detect the acoustic signal can be manufactured at low cost.

The present invention is not limited to the above embodiment, and can be substituted without departing from the spirit of the claims.

For example, in the above embodiment, the vibrating membrane 21 and the coil portion 32 are held at a predetermined interval so that the inductance of the coil portion 32 of the LC oscillation circuit 31 changes when the vibrating membrane 21 of the vibrating membrane unit 1 vibrates. An example in which the present invention is applied to the method of manufacturing the vibrating membrane unit 1 used in the semiconductor microphone M that demodulates the change in the oscillation frequency of the LC oscillation circuit 31 that changes according to the change in the inductance is shown. The present invention can also be applied to a method of manufacturing the diaphragm unit 1 used for other microphones (for example, condenser microphones).

The above-described embodiment is merely an example, and the scope of the present invention should not be interpreted in a limited manner. The scope of the present invention is defined by the scope of the claims, and all modifications and changes belonging to the equivalent scope of the claims are within the scope of the present invention.

The present invention is useful for a method of manufacturing a diaphragm unit used in a microphone, and in particular, the diaphragm and the coil so that the inductance of the coil of the LC oscillation circuit changes when the diaphragm of the diaphragm unit vibrates. Is useful for a method of manufacturing a diaphragm unit used in a semiconductor microphone that demodulates a change in oscillation frequency of an LC oscillation circuit that changes depending on the change in inductance.

DESCRIPTION OF SYMBOLS 1 Vibration membrane unit 11 Cylindrical support member 12 1st end surface 14 2nd end surface 16 Groove part 17 Dividing part 18 Meat stealing part 21 Vibration film 51 Annular jig | tool 55 Tension ring M Semiconductor microphone

Claims (5)

A resin-made cylindrical support member having at least one side opening in the axial direction and an opening peripheral edge of the first end surface that is the end surface on the one side in the axial direction of the cylindrical support member cover the opening of the first end surface. A vibration membrane unit for use in a microphone having a vibration membrane fixed as described above,
A fixing step in which the vibrating membrane is fixed to the opening peripheral edge of the first end surface of the cylindrical support member;
A method of manufacturing a diaphragm unit including a tension applying step of applying a predetermined tension to the diaphragm using the deformation of the cylindrical support member radially outward after the fixing step. In the manufacturing method of the diaphragm unit according to claim 1,
The cylindrical support member has a plurality of grooves having a predetermined depth extending radially from the inner peripheral surface to the outer peripheral surface of the cylindrical support member at a first end surface thereof, spaced apart from each other in the circumferential direction. The portion on the first end face side of the cylindrical support member is divided into a plurality of divided portions arranged in the circumferential direction,
In the fixing step, the vibrating membrane is fixed to the opening peripheral portion of the first end surface of the cylindrical supporting member by molding the cylindrical supporting member so as to be integrated with the previously prepared vibrating membrane. Is the process
In the tension applying step, a predetermined tension is applied to the vibrating membrane by deformation of the cylindrical support member in the radial direction that occurs as the temperature of the cylindrical support member after molding decreases. A method of manufacturing a diaphragm unit, which is a step of In the manufacturing method of the diaphragm unit according to claim 2,
The said cylindrical support member is a manufacturing method of a diaphragm unit in which the meat stealing part which dents this internal peripheral surface is formed in the internal peripheral surface of each said division | segmentation part. In the manufacturing method of the diaphragm unit according to claim 1,
In the fixing step, at least the first end surface side end portion of the cylindrical support member is elastically deformed radially inward by pressing, and the opening peripheral portion of the first end surface of the cylindrical support member is It is a step of fixing the vibration membrane by welding or adhesive,
The tension applying step is a step of applying a predetermined tension to the vibrating membrane by releasing the pressure and deforming the cylindrical support member radially outward due to an elastic restoring force generated by the release. Manufacturing method of vibration membrane unit. In the manufacturing method of the diaphragm unit according to claim 1,
The cylindrical support member is opened on both axial sides thereof,
The fixing step is a step of fixing the vibrating membrane to the opening peripheral edge portion of the first end surface of the cylindrical support member by welding or an adhesive,
In the tension applying step, a tension ring whose outer diameter is larger than the inner diameter of the cylindrical support member is formed from the opening of the second end surface that is the end surface opposite to the first end surface of the cylindrical support member. And inserting at least a first end face side end of the cylindrical support member with the tension ring so as to be deformed radially outward and applying a predetermined tension to the vibrating membrane by the deformation. A method for manufacturing a diaphragm unit.

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