JP2011172038A - Capacitor microphone and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a sensitivity from becoming instable in a capacitor microphone configured by cutting out a vibrating film sub-assembly, a spacer and an annular member from a layered aggregate sheet as a layering unit. <P>SOLUTION: Projections 30b, 24b are formed, respectively, in eight positions on an outer circumferential surface 30a of a support ring 30 and an outer circumferential surface 24a of a spacer 24 as an upper layering unit 14. The projections 30b and the projections 24b are formed in positions deviated from each other in a circumferential direction. When cutting out the upper layering unit 14, burrs are generated in distal end portions of the projections 30b, 24b, but because both the projections 30b, 24b are formed in the positions deviated from each other in the circumferential direction, peeling-off of a vibrating film 28 is prevented from occurring by forming a gap between both the projections like the case where both the projections are piled up in a laminating direction, and thereby the tension of the vibrating film 28 is prevented from being varied. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a small-sized condenser microphone, and more particularly to a condenser microphone in which a diaphragm subassembly, a spacer, and an annular member are cut out from a laminated assembly sheet as a laminated unit, and a manufacturing method thereof.

  In general, in a small condenser microphone, a diaphragm subassembly, in which a diaphragm is stretched and fixed to the lower surface of a support ring, and a back electrode plate, with a back electrode plate facing down, via an annular spacer The capacitor structure is configured by being disposed opposite to each other.

  In such a condenser microphone, as described in, for example, “Patent Document 1”, an annular member arranged so as to surround the back electrode plate fixes and supports the outer peripheral edge of the spacer from the lower side. Often composed.

As a method of manufacturing such a condenser microphone, as described in “Patent Document 1”, a large number of diaphragm subassemblies, spacers, and annular members are cut out from a laminated assembly sheet as a laminated unit. Things have been done.
JP 2007-208588 A

  As described above, when a plurality of stacked units are cut out from the stacked assembly sheet, a plurality of support ring assembly sheets in which a plurality of support rings are connected to each other via a plurality of first beam portions as the stacked assembly sheet; And a spacer assembly sheet in which the spacers are connected to each other via a plurality of second beam portions, and are laminated via the diaphragm assembly sheet for the diaphragm. If an annular member assembly sheet in which members are connected to each other via a strip plate portion is laminated, the laminated assembly sheet can be easily cut at the first beam portion, the second beam portion, and the strip plate portion. Is possible.

  However, when such a laminated assembly sheet is adopted, when each first beam portion of the support ring assembly sheet and each second beam portion of the spacer assembly sheet are formed at positions overlapping in the lamination direction, There are the following problems.

  That is, in each laminated unit cut out from the laminated assembly sheet, the front end surface is flush with the outer circumferential surface of the annular member at a plurality of locations on the outer circumferential surface of the support ring and the outer circumferential surface of the spacer of the diaphragm subassembly. Protrusions that protrude from the surface are respectively formed. At this time, since both the projecting portions are formed by cutting the first beam portion and the second beam portion, burrs are inevitably generated at the tip portions of these projecting portions, thereby overlapping in the stacking direction. As a result, a gap is formed between the two projecting portions at the above positions. If such a gap is formed, the vibration film is likely to be peeled off, resulting in variations in the tension of the vibration film, which causes the sensitivity of the condenser microphone to become unstable. is there.

  The present invention has been made in view of such circumstances. In the condenser microphone in which the diaphragm subassembly, the spacer, and the annular member are cut out from the laminated assembly sheet as a laminated unit, the sensitivity is unstable. It is an object of the present invention to provide a condenser microphone and a method for manufacturing the same that can prevent the occurrence of the phenomenon.

  The present invention is intended to achieve the above object by devising the structure of the support ring and spacer of the diaphragm subassembly.

That is, the condenser microphone according to the present invention is
A diaphragm sub-assembly in which the diaphragm is stretched and fixed to the lower surface of the support ring, an annular spacer joined to the lower surface of the diaphragm sub-assembly, and an annular structure for fixing and supporting the outer peripheral edge of the spacer from the lower side In a condenser microphone having a laminated unit composed of members,
The support ring and the spacer have a smaller outer shape than the annular member in plan view;
First protrusions are formed at a plurality of locations on the outer peripheral surface of the support ring so that the front end surface is flush with the outer peripheral surface of the annular member, and at the plurality of locations on the outer peripheral surface of the spacer A second protrusion is formed to protrude so that the surface is flush with the outer peripheral surface of the annular member;
Each said 1st projection part and each said 2nd projection part are formed in the position mutually shifted | deviated to the circumferential direction, It is characterized by the above-mentioned.

  In the above configuration, the terms indicating the direction such as “lower surface” and “lower side” are used for the sake of convenience in order to clarify the positional relationship between the members constituting the condenser microphone. The directionality when actually using the microphone is not limited.

  The specific outer peripheral shape of each of the “support ring”, “spacer”, and “annular member” is not particularly limited.

  The “first protrusions” are formed at a plurality of locations on the outer peripheral surface of the support ring, but the specific number and location of the formation are not particularly limited. The width and specific shape of the “part” are not particularly limited.

  The “second protrusions” are formed at a plurality of locations on the outer peripheral surface of the spacer. However, if the positions are shifted in the circumferential direction with respect to the first protrusions, the specific number of formations and formation locations are as follows. Is not particularly limited, and the width and specific shape of each “second protrusion” are not particularly limited.

On the other hand, a method of manufacturing a condenser microphone according to the present invention is a method of manufacturing the above condenser microphone,
A support ring assembly sheet in which a plurality of the support rings are connected to each other via a plurality of first beam portions, and a plurality of the spacers are positioned so as not to overlap each other in the stacking direction with each of the plurality of first beam portions. A spacer assembly sheet connected via a plurality of second beam portions formed respectively is laminated via the diaphragm assembly sheet for the diaphragm, and a plurality of the above-described spacer assembly sheets After producing the laminated assembly sheet by laminating the annular member assembly sheet in which the annular members are connected to each other through the band plate portion,
The laminated unit sheet is cut at the first beam portion, the second beam portion, and the strip plate portion to produce a plurality of the laminated units.

  The specific width and formation range of the “band plate portion” are not particularly limited as long as the “band plate portion” is wider and wider than each of the “beam portions”.

  As shown in the above configuration, in the condenser microphone according to the present invention, the support ring and the spacer constituting the laminated unit have a smaller outer shape than the annular member in plan view, and the support ring First protrusions that protrude so that the front end surface is flush with the outer peripheral surface of the annular member are formed at a plurality of locations on the outer peripheral surface, and the front end surface is the outer periphery of the annular member at a plurality of locations on the outer peripheral surface of the spacer. The second protrusions that protrude so as to be flush with the surface are formed. At this time, the first protrusions and the second protrusions are shifted from each other in the circumferential direction. Since it is formed, the following effects can be obtained.

  That is, when the laminated unit is cut out from the laminated assembly sheet, burrs are generated at the tip of each first protrusion in the support ring and the tip of each second protrusion in the spacer. Since the second protrusions are formed at positions shifted from each other in the circumferential direction, a gap is formed between each first protrusion and each second protrusion as in the case where they overlap in the stacking direction. It is possible to prevent the vibration film from being peeled off due to the formation of. As a result, it is possible to prevent the sensitivity of the condenser microphone from becoming unstable due to variations in the tension of the diaphragm.

  As described above, according to the present invention, in the condenser microphone in which the diaphragm subassembly, the spacer, and the annular member are cut out from the laminated assembly sheet as the laminated unit, the sensitivity is prevented from becoming unstable. be able to.

  In the above configuration, the outer peripheral shapes of the support ring and the spacer are not particularly limited as described above. However, when both the support ring and the spacer have a substantially rectangular outer shape, the support ring In each of at least two vertical plane portions of the four vertical plane portions constituting the outer peripheral surface, the first protrusion portion of the support ring is formed at a position deviated from the center position in the circumferential direction. And the second protrusion of the spacer at a position deviating from the center position in the circumferential direction in each of at least two of the four vertical plane portions constituting the outer peripheral surface of the spacer. If it is set as the structure in which the part was formed, the following effects can be acquired.

  That is, in order to set the sensitivity of the condenser microphone to a high value, it is preferable to make the outer peripheral edge shape of the vibration surface of the vibration membrane as close to a circle as possible. At this time, if the support ring has a substantially rectangular outer shape, the outer periphery of the vertical plane portion and the vibration surface are arranged at the center position in the circumferential direction of each vertical plane portion constituting the outer peripheral surface. The distance to the periphery is the shortest.

  Therefore, assuming that the first protrusion is formed at the center position in the circumferential direction of each vertical plane portion of the support ring, when the stacked unit is cut out from the stacked assembly sheet, the first protrusion is formed at the tip of each first protrusion. In addition to the occurrence of burrs, each of the first protrusions and their peripheral portions are bent and deformed, and this causes variations in the tension of the vibration film. Similarly, assuming that the second protrusion is formed at the center position in the circumferential direction of each vertical plane portion of the spacer, when the stacked unit is cut out from the stacked assembly sheet, it is formed at the tip of each of the second protrusions. In addition to the occurrence of burrs, each of the second projecting portions and the peripheral portions thereof are bent and deformed, which causes variations in the tension of the vibrating membrane.

  On the other hand, if each first protrusion is configured to be formed at a position that deviates from the center position in the circumferential direction in the vertical plane portion of the support ring where the first protrusion is formed, the bending deformation Can be effectively suppressed from reaching the peripheral portion of each first protrusion. Further, if each of the second protrusions is configured to be formed at a position deviated from the center position in the circumferential direction in the vertical plane portion of the spacer on which the second protrusion is formed, the bending deformation is caused by each of the second protrusions. It is possible to effectively suppress the peripheral portion of the two protrusions. As a result, it is possible to more reliably prevent variations in the tension of the vibration film.

  At this time, if the first protrusion is formed on each of at least two vertical planes among the four vertical planes constituting the outer peripheral surface of the support ring, the vertical plane to be formed is formed. The position and the number of the portions are not particularly limited, and the second protrusions are formed on each of at least two vertical plane portions among the four vertical plane portions constituting the outer peripheral surface of the spacer. If it is, the position and the number of the vertical plane portions to be formed are not particularly limited.

  In this case, if any one of the first protrusions and the second protrusions is formed in the vicinity of the corner portion on the outer peripheral surface of the support ring or the outer peripheral surface of the spacer, Such effects can be obtained.

  That is, when the laminated unit is cut out from the laminated assembly sheet, the outer peripheral edge portion of the vibration film is protruded from the support ring and the spacer to the outer peripheral side. Of these protruding portions, each of the first protrusions Except for the portion joined to the lower surface or the upper surface of each second protrusion, the state is free. And when the free part of this vibration film is located in the corner part of a lamination | stacking unit, this free part becomes easy to bend. For this reason, when the laminated unit is incorporated as a part of a condenser microphone, the free part of the vibrating membrane in the bent state is placed at an inappropriate position, for example, between the metal case housing the laminated unit and the support ring. There is a possibility of being pinched, which may cause an assembly failure.

  On the other hand, if any one of the first protrusions and the second protrusions is formed in the vicinity of the corner portion on the outer peripheral surface of the support ring or the outer peripheral surface of the spacer, the corner portion of the multilayer unit is formed. It is possible to reduce the size of the free portion of the vibration film formed on the substrate. As a result, it is possible to prevent the free portion from being caught and caught between inappropriate portions.

  On the other hand, in the method of manufacturing a condenser microphone according to the present invention, when the laminated assembly sheet is manufactured, the first beam portions of the support ring assembly sheet and the second beam portions of the spacer assembly sheet do not overlap each other in the stacking direction. Since it is formed at the position, the above-described effects can be reliably obtained also in terms of manufacturing.

The sectional side view shown in the state where the condenser microphone concerning one embodiment of the invention of this application was arranged upwards The perspective view which decomposes | disassembles the said capacitor | condenser microphone into main components and it sees from diagonally upward The perspective view which decomposes | disassembles the said condenser microphone into main components and sees it from diagonally downward The top view which shows the manufacturing process of the upper lamination | stacking unit of the said capacitor microphone 4A is a detailed cross-sectional view taken along the line Va-Va in FIG. 4, and FIG. FIG. 5A is a detailed view of the VIa portion of FIG. 5B, and FIG.

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

  FIG. 1 is a side cross-sectional view showing a condenser microphone 10 according to an embodiment of the present invention in an upwardly arranged state. FIGS. 2 and 3 are perspective views of the condenser microphone 10 which is disassembled into main components and viewed from obliquely above and obliquely below.

  As shown in these drawings, the condenser microphone 10 according to this embodiment is a small electret condenser microphone, and includes an upper laminated unit 14, a back electrode plate 16, a contact spring 18, and a lower laminated unit in a metal case 12. 20 is accommodated.

  First, the metal case 12 will be described.

  The metal case 12 is a cap-shaped member having a substantially rectangular outer shape of about 3 × 4 mm in plan view, and is formed by pressing a metal plate (for example, an aluminum plate).

  In the metal case 12, sound holes 12a are formed in the upper surface wall 12A, and the extension pieces 12b extending downward from the lower edge of the four vertical plane portions of the peripheral wall 12B. Are formed respectively. The metal case 12 is caulked and fixed to the lower laminated unit 20 at the four extension pieces 12b.

  Next, the upper laminated unit 14 will be described.

  The upper laminated unit 14 includes a diaphragm subassembly 22, an annular spacer 24 bonded and fixed to the lower surface of the diaphragm subassembly 22, and an annular member 26 bonded and fixed to the lower surface of the spacer 24. Yes.

  In the diaphragm sub-assembly 22, the diaphragm 28 is stretched and fixed to the lower surface of the support ring 30 (that is, fixed by adhesion or the like in a tensioned state). The vibration film 28 has a metal vapor deposition film formed on the upper surface of a polymer film having a thickness of about 1.5 to 3 μm.

  The support ring 30 is made of a thin metal plate having a thickness of about 50 μm. The outer peripheral surface shape of the support ring 30 is set to a substantially rectangular shape that is slightly smaller than the peripheral surface wall 12B of the metal case 12, and the inner peripheral surface shape is set to a substantially elliptical shape extending in the longitudinal direction of the metal case 12. Has been. And the protrusion part 30b which protrudes to an outer peripheral side is formed in eight places on the outer peripheral surface 30a of this support ring 30 (this is mentioned later). The support ring 30 is formed with circular small holes 30c for adjusting the atmospheric pressure in the vicinity of the two corners on the diagonal line.

  The spacer 24 is composed of a thin metal plate having a thickness of about 25 μm. The outer peripheral surface shape of the spacer 24 is set to the same shape as the outer peripheral surface shape of the support ring 30, and the inner peripheral surface shape is set to be substantially the same shape as the inner peripheral surface shape of the support ring 30. Yes. And, on the outer peripheral surface 24a of the spacer 24, protrusions 24b protruding to the outer peripheral side are formed at eight locations (this will also be described later). The spacer 24 is formed with oval small holes 24c for adjusting atmospheric pressure so as to overlap with the small holes 30c of the support ring 30 in the vicinity of the two corners on the diagonal line. Yes.

  The annular member 26 is a substantially rectangular annular member that supports the outer peripheral edge portion of the spacer 24 from the lower side around the back electrode plate 16, and is made of glass cloth base epoxy resin having a plate thickness of about 0.3 mm. It is configured as a substrate.

  The annular member 26 is formed such that an outer peripheral surface 26 a thereof is substantially inscribed in the peripheral wall 12 B of the metal case 12. Specifically, the outer peripheral surface 26a of the annular member 26 is formed such that the four vertical plane portions thereof extend along the four vertical plane portions in the peripheral wall 12B of the metal case 12, and The four corner portions are cut out in an arc shape in plan view.

  The inner peripheral surface 26b of the annular member 26 has a substantially oval shape extending in the longitudinal direction of the metal case 12 in plan view. At this time, the inner peripheral surface 26b of the annular member 26 substantially coincides with the position of the inner peripheral surface of the spacer at both end positions in the longitudinal direction and both end positions in the orthogonal direction, but at the four corner positions. The diameter is larger than the position of the inner peripheral surface of the spacer 24. A part of each small hole 24 c of the spacer 24 is exposed in a space on the inner peripheral side of the inner peripheral surface 26 b of the annular member 26.

  Next, the back electrode plate 16 will be described.

  The back electrode plate 16 includes an electrode plate body 16A made of a metal plate having a thickness of about 0.1 mm, and an electret layer 16B disposed on the upper surface of the electrode plate body 16A. A through hole 16a is formed. At that time, the electret layer 16B is generated by subjecting the insulating film formed on the upper surface of the electrode plate main body 16A to a thickness of about 10 to 30 μm by polarization treatment with a predetermined charge voltage. A potential is applied.

  The back electrode plate 16 has a substantially rectangular outer shape with corners R provided at the four corners in plan view, and the outer peripheral surface thereof is substantially internal at a plurality of locations with respect to the inner peripheral surface 26 b of the annular member 26. In a state of being in contact, the annular member 26 is disposed in the inner peripheral space. At this time, the back electrode plate 16 is in contact with the four corners of the lower surface of the spacer 24 at the four corners of the upper surface.

  The electret layer 16 </ b> B of the back electrode plate 16 and the vibration film 28 are disposed to face each other with the spacer 24 interposed therebetween, whereby the capacitor structure portion C is configured.

  Next, the lower laminated unit 20 will be described.

  The lower laminated unit 20 includes a circuit board 32 arranged in parallel with the electret layer 16B, an impedance conversion element 34 mounted substantially at the center of the upper surface of the circuit board 32, and a circuit board surrounding the impedance conversion element 34. And an annular substrate 36 mounted and fixed on the upper surface of 32.

  The lower laminated unit 20 is in contact with the lower surface of the annular member 26 in the upper laminated unit 14 on the upper surface of the annular substrate 36, and in this state, each extension piece of the metal case 12 is attached to each side portion of the circuit substrate 32. 12b is fixed by caulking.

  The circuit board 32 has a conductive layer formed in a predetermined pattern on the upper and lower surfaces and in the middle of an insulating substrate having a substantially same outer peripheral shape as the annular member 26 and a thickness of about 0.15 mm. It has a configuration. At this time, a part of the conductive layer formed on the upper surface of the circuit board 32 constitutes a first conductive layer 32 a that is electrically connected to the input terminal 34 a of the impedance conversion element 34.

  The impedance conversion element 34 is configured as an IC chip having a flat rectangular parallelepiped outer shape, and has a rectangular shape that is slightly longer in the longitudinal direction of the metal case 12 in plan view. The impedance conversion element 34 has an upper surface located at a height of about 0.4 mm from the upper surface of the circuit board 32.

  The annular substrate 36 has a configuration in which conductive layers are respectively formed in a predetermined pattern on both upper and lower surfaces of an insulating substrate having the same outer peripheral shape as the circuit substrate 32 and having a thickness of about 0.3 mm. Yes.

  The inner peripheral surface 36b of the annular substrate 36 has a substantially oval shape extending in the longitudinal direction of the metal case 12 in plan view. At this time, the substantially oval shape constituting the inner peripheral surface 36b is such that three cylinders having a diameter larger than the lateral width of the impedance conversion element 34 are partially connected to each other on the center of the annular substrate 36 and on both longitudinal sides thereof. It has a shape that is arranged in an overlapping state.

  A second conductive layer 36 c that is electrically connected to the first conductive layer 32 a of the circuit substrate 32 is formed on the inner peripheral surface 36 b of the annular substrate 36 so as to extend from the lower surface to the upper surface of the annular substrate 36.

  The second conductive layer 36 c is formed as a part of the conductive through hole so as to extend along the inner peripheral surface 36 b of the annular substrate 36 at two locations on both sides of the impedance conversion element 34. That is, the second conductive layer 36c is formed with a through hole having a diameter slightly larger than the conductive through hole on both sides in the longitudinal direction by drilling or the like after forming a conductive through hole in the center of the annular substrate 36. It is formed by partially cutting away the conductive through hole.

  Next, the contact spring 18 will be described.

  The contact spring 18 is disposed below the back electrode plate 16 and elastically presses the back electrode plate 16 upward.

  The contact spring 18 is a metal leaf spring, and is formed by pressing a leaf spring material having a plate thickness of about 50 μm.

  The contact spring 18 is formed in a substantially rectangular ring shape in a plan view in an unloaded state. At that time, the longitudinal central portion 18A of the contact spring 18 extends in the horizontal direction, but both longitudinal end portions 18B extend in a straight line obliquely upward. Then, four spherical convex portions 18a projecting downward are formed in the longitudinal direction central portion 18A of the contact spring 18 at a predetermined interval in the longitudinal direction. In addition, four spherical convex portions 18b projecting upward are formed at the four corners at both longitudinal ends 18B of the contact spring 18, respectively.

  When the contact spring 18 is incorporated as a part of the condenser microphone 10, the outer circumferential surface of the contact spring 18 is substantially inscribed to the inner circumferential surface 26 b of the annular member 26 at a plurality of locations, and the inner circumferential space of the annular member 26 is used. It is supposed to be arranged in. In this state, the contact spring 18 is in a state in which the longitudinal center portion 18A and the pair of longitudinal end portions 18B extend substantially along the same horizontal plane due to bending deformation in the vertical direction.

  At this time, the contact spring 18 is in contact with the lower surface of the back electrode plate 16 at the four spherical convex portions 18b located at the upper end portion thereof, and the four spherical convex portions 18a located at the lower end portion thereof. In this case, the pair of second conductive layers 36 c are in contact with the upper surface portion of the annular substrate 36. The contact spring 18 and the first and second conductive layers 32 a and 36 c are used to electrically connect the back electrode plate 16 and the input terminal 34 a of the impedance conversion element 34.

  In the contact spring 18, the formation positions of the respective spherical convex portions 18 a are set so that the four spherical convex portions 18 a are surely in contact with the pair of second conductive layers 36 c two by two. . Further, in the contact spring 18, the four spherical convex portions 18 b are in contact with the lower surface of the four corners of the back electrode plate 16 (that is, the portion where the back electrode plate 16 is in contact with the spacer 24). It has become.

  Next, the detailed structure of the upper laminated unit 14 will be described.

  In the upper laminated unit 14, the four vertical flat portions on the outer peripheral surfaces 30 a and 24 a of the support ring 30 and the spacer 24 are slightly on the inner peripheral side (4 on the outer peripheral surface 26 a of the annular member 26 ( Specifically, it is formed so as to extend in parallel with the vertical plane portion on the inner peripheral side of about 0.1 to 0.15 mm.

  The protrusions 30b and 24b formed at eight locations on the outer peripheral surfaces 30a and 24a of the support ring 30 and the spacer 24 protrude so that the front end surfaces thereof are flush with the outer peripheral surface 26a of the annular member 26. .

  At that time, the eight protrusions 30b of the support ring 30 are formed at two positions in each of the four vertical plane portions on the outer peripheral surface 30a at positions away from the center position in the circumferential direction, The eight protrusions 24b of the spacer 24 are formed in two positions at positions away from the center position in the circumferential direction in each of the four vertical plane portions on the outer peripheral surface 24a.

  Specifically, each protrusion 24b of the spacer 24 is formed with a width of about 0.15 mm in the vicinity of the corner portion on the outer peripheral surface 30a, and the support ring 30 is located slightly away from each of the protrusions 24b. Each protrusion 30b is formed with a width of about 0.15 mm.

  FIG. 4 is a plan view showing a manufacturing process of the upper laminated unit 14. 5A is a detailed cross-sectional view taken along the line Va-Va in FIG. 4, and FIG. 5B is a related diagram thereof.

  As shown in these drawings, the upper laminated unit 14 is manufactured as follows.

  First, as shown in FIGS. 4 and 5 (a), a support ring assembly sheet in which a plurality of support rings 30 (see FIG. 5 (b)) are connected to each other in two orthogonal directions via beam portions 130a. 130, a plurality of spacers 24 (see FIG. 5B) are connected to each other in two orthogonal directions via beam portions 124a, and a plurality of annular members 26 (FIG. 5B). Each of the annular member assembly sheets 126 connected to each other in two directions orthogonal to each other via the band plate portion 126a. At this time, small holes 130b to be the small holes 30c (see FIG. 2) for adjusting the atmospheric pressure of the support ring 30 are formed in the support ring assembly sheet 130 in advance. In the annular member assembly sheet 126, through holes 126b having a circular planar shape are formed in advance at the positions of the respective lattice points arranged in the two directions by drilling.

  Next, the diaphragm assembly sheet 128 for the diaphragm 28 (see FIG. 5B) is stretched and fixed to the lower surface of the support ring assembly sheet 130. Then, the spacer assembly sheet 124 and the annular member assembly sheet 126 are joined to the support ring assembly sheet 130 in which the diaphragm assembly sheet 128 is stretched and fixed to the lower surface in a state where the spacer assembly sheet 124 and the annular member assembly sheet 126 are laminated in this order. By doing so, an upper laminated assembly sheet 114 in which a plurality of upper laminated units 14 are connected to each other in two orthogonal directions is manufactured. And the part located in each through-hole 126b and each small hole 130b in the diaphragm assembly sheet 128 of this upper laminated assembly sheet 114 is removed by laser light irradiation or the like.

  Next, at the connecting position between the upper laminated units 14 in the upper laminated aggregate sheet 114, each beam portion 130a of the support ring aggregate sheet 130, each beam portion 124a of the spacer aggregate sheet 124, and each band of the annular member aggregate sheet 126. The plate part 126a is cut. In this cutting, the rotary blade 102 indicated by a two-dot chain line in FIG. 5A is used, and the rotary blade 102 is pressed against the upper laminated assembly sheet 114 from above the upper laminated assembly sheet 114. In FIG. 4, by moving along a path 114a indicated by a two-dot chain line, the cutting width is about 0.25 mm.

  As shown in FIG. 5B, the upper laminated units 14 cut out in this way are arranged so that the tip surfaces of the protrusions 30 b in the support ring 30 of the vibration membrane subassembly 22 and the protrusions 24 b of the spacer 24 are formed. The front end surface is formed flush with each vertical plane portion on the outer peripheral surface 26 a of the annular member 26.

  FIG. 6A is a detailed view of the VIa portion of FIG.

  As described above, the upper laminated unit 14 is cut out from the upper laminated sheet 114. At that time, the upper laminated sheet 114 is cut in a state where the rotary blade 102 is pressed from the upper side. As shown in FIG. 6A, downward burrs 30b1 and 24b1 are generated at the tips of the protrusions 30b and 24b in the support ring 30 and the spacer 24, and the protrusions 30b and 24b are formed. Is bent downward and deformed.

  At that time, since the spacer 24 is in surface contact with the upper surface of the annular member 26, each protrusion 24 b is bent and deformed so that the burr 24 b 1 bites into the annular member 26. However, the spacer 24 does not bend and deform to the peripheral portions of the protrusions 24b.

  On the other hand, the support ring 30 is separated from the upper surface of the annular member 26 by the thickness of the spacer 24, and each protrusion 30 b is shifted in the circumferential direction with respect to each protrusion 24 b of the spacer 24. Therefore, each of the protrusions 30b is bent and deformed downward as a cantilever, and the burr 30b1 hardly bites into the annular member 26. In addition, the support ring 30 is not bent and deformed to the peripheral portions of the protrusions 30b.

  Next, the effect of this embodiment is demonstrated.

  In the condenser microphone 10 according to the present embodiment, the support ring 30 and the spacer 24 constituting the upper laminated unit 14 as the laminated unit have an outer shape smaller than the annular member 26 in plan view, and The protrusions 30 b are formed as first protrusions that protrude so that the front end surface is flush with the outer peripheral surface 26 a of the annular member 26 at eight locations on the outer peripheral surface 30 a of the support ring 30. Protrusions 24b are formed at the eight locations on the surface 24a as second protrusions that protrude so that the tip surface is flush with the outer peripheral surface of the annular member 26. Since 30b and each protrusion part 24b are formed in the position which mutually shifted | deviated to the circumferential direction, the following effects can be acquired.

  That is, when the upper laminated unit 14 is cut out from the upper laminated sheet 114, burrs 30b1 and 24b1 are generated at the tip of each protrusion 30b in the support ring 30 and the tip of each protrusion 24b in the spacer 24. Each protrusion 30b and each protrusion 24b are formed at positions shifted from each other in the circumferential direction, so that each protrusion 30b and each protrusion 24b are in the same direction as when they overlap each other in the stacking direction. It is possible to prevent the vibration film 28 from being separated due to the formation of a gap therebetween. As a result, it is possible to prevent the sensitivity of the condenser microphone 10 from becoming unstable due to variations in the tension of the vibration film 28.

  This point will be specifically described below using a comparative example for the present embodiment.

  FIG. 6B is a view similar to FIG. 6A showing the configuration of the upper laminated unit 14 ′ according to this comparative example.

  In this upper laminated unit 14 ′, the annular member 26 ′ has the same configuration as the annular member 26 of the upper laminated unit 14, but the support ring 30 ′ and the spacer 24 ′ are the same as the support ring 30 and the upper laminated unit 14. The spacer 24 has a different configuration.

  That is, in the upper laminated unit 14 ′, the protrusions 30b ′ and 24b ′ of the support ring 30 ′ and the spacer 24 ′ are located at the center positions in the circumferential direction of the vertical plane portions of the outer peripheral surfaces 30a ′ and 24a ′. It is the structure formed in the state which overlapped in the lamination direction.

  Therefore, in this upper laminated unit 14 ′, the upper ring assembly sheet is cut out from the upper laminated assembly sheet, so that the protrusions 30b ′ and 24b ′ of the support ring 30 ′ and the spacer 24 ′ are respectively directed downward. Burrs 30b1 ′ and 24b1 ′ are generated, and the protrusions 30b ′ and 24b ′ are bent downward and deformed.

  For this reason, in this upper laminated unit 14 ', a gap is formed between the two protrusions 30b' and 24b 'located at the positions overlapping in the laminating direction. When such a gap is formed, the vibration film 28 ′ is easily peeled off from the support ring 30 ′ (FIG. 6B shows a state where peeling occurs). Accordingly, this may cause variations in the tension of the vibration film 28 ′, which may make the sensitivity of the condenser microphone unstable.

  On the other hand, in the upper laminated unit 14 of this embodiment shown in FIG. 6A, the protrusions 30b of the support ring 30 and the protrusions 24b of the spacer 24 are arranged at positions shifted from each other in the circumferential direction. Therefore, the vibration film 28 does not peel from the support ring 30 due to being cut out from the upper laminated sheet 114. For this reason, the tension of the vibration film 28 does not vary and the sensitivity of the condenser microphone 10 does not become unstable.

  As described above, according to the present embodiment, the sensitivity of the condenser microphone 10 in which the diaphragm subassembly 22, the spacer 24, and the annular member 26 are cut out from the upper laminated assembly sheet 114 as the upper laminated unit 14 is unstable. It can be prevented beforehand.

  At this time, in the condenser microphone 10 according to the present embodiment, the support ring 30 and the spacer 24 both have a substantially rectangular outer shape, but the protrusion 30b of the support ring 30 has an outer peripheral surface 30a. Are formed at positions deviating from the center position in the circumferential direction, and the protrusion 24b of the spacer 24 constitutes the outer peripheral surface 24a. Since each of the four vertical plane portions is formed at a position deviated from the center position in the circumferential direction, the following operational effects can be obtained.

  That is, in the condenser microphone 10 according to the present embodiment, the outer peripheral edge shape of the vibration surface of the vibration film 28 is set to a substantially elliptical shape in order to set the sensitivity to a high value. The distance between the vertical plane portion and the outer peripheral edge of the vibration surface is the shortest at the center position in the circumferential direction of each vertical plane portion constituting the.

  Therefore, as in the upper laminated unit 14 ′ shown in FIG. 6B, each protrusion 30b ′ of the support ring 30 ′ is formed at the center position in the circumferential direction of each vertical plane portion of the outer peripheral surface 30a ′. If the upper laminated unit 14 ′ is cut out, the burr 30b1 ′ is generated at the tip of each projection 30b ′ and not only the projection 30b ′ is bent and deformed, but also in the support ring 30 ′. Since the bending deformation also occurs in the peripheral portion of each protrusion 30b ', this causes variations in the tension of the vibration film 28'. Similarly, assuming that each protrusion 24b ′ of the spacer 24 ′ is formed at the center position in the circumferential direction of each vertical plane portion of the outer peripheral surface 24a, when the upper stacked unit 14 ′ is cut out, each protrusion Since the burr 24b1 'is generated at the tip of the portion 24b' and not only the deformation of each projection 24b 'is deformed, but also the deformation of the peripheral portion of each projection 24b' in the spacer 24 'is caused. This causes variations in the tension of the vibration film 28 '.

  On the other hand, in the upper laminated unit 14 of the present embodiment, each protrusion 30b of the support ring 30 is formed at a position deviated from the center position in the circumferential direction in each vertical plane portion of the outer peripheral surface 30a. In addition, it is possible to effectively suppress the bending deformation from reaching the peripheral portion of each protrusion 30b, and each protrusion 24b of the spacer 24 is circumferential in each vertical plane portion of the outer peripheral surface 24a. Therefore, it is possible to effectively suppress the bending deformation from reaching the peripheral portion of each projection 24b. As a result, it is possible to more reliably prevent the variation in the tension of the vibration film 28 from occurring.

  In addition, in the present embodiment, since each protrusion 24b of the spacer 24 is formed in the vicinity of the corner portion on the outer peripheral surface 30a, the following operational effects can be obtained.

  That is, when the upper laminated unit 14 is cut out from the upper laminated sheet 114, the outer peripheral edge portion of the vibration film 28 protrudes to the outer peripheral side from the support ring 30 and the spacer 24. The portions other than the portion joined to the lower surface of each protrusion 30b or the upper surface of each protrusion 24b are in a free state. And when the free part of this vibration film 28 is located in the corner part of the upper lamination | stacking unit 14, this free part becomes easy to bend. For this reason, when the upper laminated unit 14 is incorporated as a part of the condenser microphone 10, the free portion of the vibrating membrane 28 in the bent state is sandwiched between the metal case 12 and the support ring 30, resulting in poor assembly. May occur.

  On the other hand, in this embodiment, each protrusion 24b of the spacer 24 is formed in the vicinity of the corner portion on the outer peripheral surface 30a, so that the vibration film 28 formed in the corner portion of the upper laminated unit 14 is free. The size of the part can be reduced. As a result, it is possible to prevent the free portion from being curled and caught between the metal case 12 and the support ring 30 in advance.

  Further, in the method of manufacturing the condenser microphone 10 according to the present embodiment, when the upper laminated assembly sheet 114 is manufactured, each beam portion 130 a as each first beam portion of the support ring assembly sheet 130 and each spacer assembly sheet 124. Since the beam portions 124a as the two beam portions are formed at positions that do not overlap with each other in the stacking direction, the above-described effects can be reliably obtained also in terms of manufacturing.

  In the embodiment described above, the protrusions 30b and 24b of the support ring 30 and the spacer 24 have been described as being formed at eight locations on the outer peripheral surfaces 30a and 24a, but instead of doing so, for example, It is also possible to adopt a configuration in which one protrusion 30b, 24b is formed on each of the four vertical plane portions of the outer peripheral surfaces 30a, 24a.

  In the above embodiment, the case where the condenser microphone 10 is an electret condenser microphone has been described. However, even in the case where the condenser microphone is configured to be applied with a bias voltage, the same operation as in the above embodiment is performed. An effect can be obtained.

  In addition, the numerical value shown as a specification in the said embodiment is only an example, and of course, you may set these to a different value suitably.

DESCRIPTION OF SYMBOLS 10 Condenser microphone 12 Metal case 12A Upper surface wall 12B Perimeter wall 12a Sound hole 12b Extension piece 14 Upper laminated unit (laminated unit)
16 Back electrode plate 16A Electrode plate body 16B Electret layer 16a Through hole 18 Contact spring 18A Longitudinal center 18B Longitudinal both ends 18a, 18b Spherical convex 20 Lower laminated unit 22 Vibration membrane subassembly 24 Spacers 24a, 26a, 30a Outer peripheral surface 24b Projection (second projection)
24b1, 30b1 Burr 24c, 30c Small hole 26 Annular member 26b, 36b Inner peripheral surface 28 Vibration membrane 30 Support ring 30b Protrusion (first protrusion)
32 circuit board 32a first conductive layer 34 impedance conversion element 34a input terminal 36 annular substrate 36c second conductive layer 102 rotary blade 114 upper laminated aggregate sheet 114a path 124 spacer aggregate sheet 124a beam part (second beam part)
126 annular member assembly sheet 126a band plate portion 126b through hole 128 diaphragm assembly sheet 130 support ring assembly sheet 130a beam portion (first beam portion)
130b Small hole C Capacitor structure

Claims (4)

A diaphragm sub-assembly in which the diaphragm is stretched and fixed to the lower surface of the support ring, an annular spacer joined to the lower surface of the diaphragm sub-assembly, and an annular structure for fixing and supporting the outer peripheral edge of the spacer from the lower side In a condenser microphone having a laminated unit composed of members,
The support ring and the spacer have a smaller outer shape than the annular member in plan view;
First protrusions are formed at a plurality of locations on the outer peripheral surface of the support ring so that the front end surface is flush with the outer peripheral surface of the annular member, and at the plurality of locations on the outer peripheral surface of the spacer A second protrusion is formed to protrude so that the surface is flush with the outer peripheral surface of the annular member;
Each of the first protrusions and each of the second protrusions are formed at positions shifted from each other in the circumferential direction. Each of the support ring and the spacer has a substantially rectangular outer shape,
The first protrusion is out of the circumferential center of the vertical plane in each of at least two of the four vertical planes constituting the outer peripheral surface of the support ring. Formed in position,
The position where the second projecting portion deviates from the center position in the circumferential direction of the vertical plane portion in each of at least two of the four vertical plane portions constituting the outer peripheral surface of the spacer. The condenser microphone according to claim 1, wherein the condenser microphone is formed as follows.   3. One of the first protrusions and the second protrusions is formed in the vicinity of a corner portion on the outer peripheral surface of the support ring or the outer peripheral surface of the spacer. The condenser microphone described. A method of manufacturing the condenser microphone according to any one of claims 1 to 3,
A support ring assembly sheet in which a plurality of the support rings are connected to each other via a plurality of first beam portions, and a plurality of the spacers are positioned so as not to overlap each other in the stacking direction with each of the plurality of first beam portions. A spacer assembly sheet connected via a plurality of second beam portions formed respectively is laminated via the diaphragm assembly sheet for the diaphragm, and a plurality of the above-described spacer assembly sheets After producing the laminated assembly sheet by laminating the annular member assembly sheet in which the annular members are connected to each other through the band plate portion,
A method of manufacturing a condenser microphone, comprising: cutting the laminated assembly sheet at the first beam portion, the second beam portion, and the strip plate portion to produce a plurality of the laminated units.

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