JP2007036386A - Method of manufacturing condenser microphone - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a condenser microphone and a manufacturing method thereof which can improve productivity and prevent the occurrence of a thermal failure caused by soldering. <P>SOLUTION: A circuit board forming member 31, a casing forming member 30, a spacer forming member 32, a diaphragm sheet 33 and a diaphragm plate forming member 34 are laminated, thereby forming a plurality of portions other than a back plate 15 and a contact spring 14 into a laminate in the condenser microphone. Also, the back plate 15 and the contact spring 14 are arranged in an air chamber formed of each of the forming members, thereby forming a plurality of condenser microphone constituents on the laminate. Next, the laminate is cut to separate the condenser microphone constituents, thereby manufacturing each of the condenser microphones. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method of manufacturing a condenser microphone used in a mobile phone, a video camera, a personal computer, and the like.

Conventionally, as this type of condenser microphone and its manufacturing method, for example, there is one described in Patent Document 1. In Patent Document 1, first, an assembly electrode substrate composed of a plurality of electrode substrates, an assembly back electrode substrate on which a plurality of back plates are fixed, an assembly spacer composed of a plurality of spacers, and a plurality of diaphragm support frames are provided. At the same time, a collective diaphragm support frame on which the diaphragms are bonded together is laminated. Thereby, the laminated body which consists of a several capacitor | condenser microphone structure is formed. Next, this laminated body is cut to separate each capacitor microphone component, and each separated capacitor microphone component is used as a capacitor microphone.
JP 2002-345092 A

  Unlike the conventional general condenser microphone manufacturing method, the condenser microphone manufactured by the manufacturing method of Patent Document 1 does not require the work of assembling the microphone assembly in the housing for each product, so that productivity is improved. To do.

  In general, a condenser microphone is mounted on a circuit board such as a mobile phone by reflow soldering. At this time, each component of the condenser microphone is thermally expanded by heat from reflow soldering. The condenser microphone manufactured by the manufacturing method of Patent Document 1 is configured using a collective back electrode substrate in which a back plate is integrated with a frame-shaped substrate body. In practice, this condenser microphone is used in a state of being housed in a metal shield case. For this reason, when heat is applied to the condenser microphone housed in the shield case, if the thermal expansion coefficient of each component of the condenser microphone is greater than the thermal expansion coefficient of the shield case, the condenser microphone is tightened to the shield case, and the spacer May be deformed to reduce its thickness. As a result, the distance between the back plate and the diaphragm becomes smaller than the set value, and the sensitivity characteristic may be deteriorated.

  An object of the present invention is to provide a method of manufacturing a condenser microphone that can improve productivity and can suppress the occurrence of thermal failure due to soldering or the like in a product.

  In order to achieve the above object, according to the first aspect of the present invention, there is provided a housing forming member having a plurality of holes for forming air chambers, and a plurality of impedance conversion circuits corresponding to the air chambers. A circuit board forming member provided, a spacer forming member for forming a plurality of spacers corresponding to each air chamber, a diaphragm sheet for forming a plurality of diaphragms corresponding to each spacer, and corresponding to each diaphragm The circuit board forming member, the casing forming member, the spacer forming member, the diaphragm sheet, and the diaphragm plate forming member are stacked using a diaphragm plate forming member for forming a plurality of diaphragm plates, and the air gap formed by stacking is used. For each chamber, the back plate and the back plate are elastically biased to contact the spacer forming member. A contact spring that is held in a closed state and is electrically connected to the impedance conversion circuit, and a laminated body composed of a plurality of condenser microphones is formed by integrally joining the laminated members, and then It is characterized in that each condenser microphone component is separated by cutting the body.

  According to a second aspect of the invention, in addition to the first aspect of the invention, the spacer forming member has a plurality of through holes that partition the spacer. It is characterized by being cut at the part.

  According to a third aspect of the present invention, in the second aspect of the present invention, the housing forming member has a plurality of through holes around the hole, and each of the through holes is cut when the laminate is cut. It is characterized by being cut at the part.

  According to a fourth aspect of the invention, in addition to the third aspect of the invention, the through hole of the spacer forming member and the through hole of the housing forming member are provided at positions corresponding to each other in the laminated body. It is characterized by being.

  According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects of the present invention, a through hole that communicates with each other is provided in the groove forming member, the diaphragm sheet, and the spacer forming member. The diaphragm plate forming member and the impedance conversion circuit are electrically connected to each other through each through hole.

  The invention according to claim 6 is the diaphragm according to any one of claims 1 to 5, wherein the spacer forming member, the diaphragm sheet, and the diaphragm plate forming member are laminated and integrated, and then the diaphragm. The assembly and the housing forming member are integrated.

  The invention according to claim 7 is the invention according to any one of claims 1 to 6, wherein a cover forming member for forming a cover that covers the diaphragm is a diaphragm plate forming member side of the laminate. After further laminating and integrating, the laminate is cut.

  According to the present invention, the circuit board forming member, the housing forming member, the spacer forming member, the diaphragm sheet, and the diaphragm plate forming member are stacked, and the back plate and the contact spring are disposed in the air chamber formed by each forming member. As a result, a laminate composed of a plurality of condenser microphone components is formed. The laminated body is cut to separate each capacitor microphone component, and each capacitor microphone component is used as a capacitor microphone. For this reason, productivity improves compared with the conventional manufacturing method which manufactures a condenser microphone one by one. Further, the back plate elastically urged by the contact spring is held in the air chamber of each condenser microphone component in contact with the spacer forming member. For this reason, heat is applied to the condenser microphone housed in the metal shield case due to reflow soldering, etc., and no force is applied to the spacer even if the condenser microphone is fastened to the shield case due to the difference in thermal expansion coefficient. . Therefore, the spacer is not deformed and its thickness is not reduced, and the distance between the back plate and the spacer is not reduced from the set value, so that the sensitivity characteristic is not deteriorated. Therefore, productivity can be improved and the occurrence of thermal failure due to soldering or the like in the product can be suppressed. In addition, the back plate is made up of independent parts and is covered with the microphone exterior parts, so heat during reflow soldering is not directly transmitted, and the back plate is heated by heat during reflow soldering. Charge attenuation can be suppressed.

  Further, if the spacer forming member has a plurality of through holes for partitioning the spacer and is cut at the portion of each through hole at the time of cutting the laminated body, the cutting resistance in cutting the laminated body is reduced. Cutting becomes easy. For this reason, the productivity of the condenser microphone is further improved.

  Further, if the casing forming member has a plurality of through holes around the hole portion and is cut at the portion of each through hole when the laminated body is cut, the cutting resistance in cutting the laminated body is reduced. It is reduced and cutting becomes easy. For this reason, the productivity of the condenser microphone is further improved.

  In addition, if the through holes of the spacer forming member and the through holes of the housing forming member are provided at positions corresponding to each other in the laminate, the laminate can be cut more easily. Productivity is further improved.

  In addition, after stacking and integrating the spacer forming member, diaphragm sheet, and diaphragm plate forming member, the diaphragm assembly and the housing forming member are integrated, and these members are stacked and integrated at once. It is easier to adjust the tension of the diaphragm. This makes it easier to manufacture a condenser microphone.

Next, an embodiment embodying the present invention will be described with reference to FIGS.
As shown in FIG. 1, the condenser microphone 10 of this embodiment has a flat box shape with a substantially square shape in plan view. As shown in FIGS. 2 and 3, the condenser microphone includes a frame-shaped casing 12, a circuit board 13, a contact spring 14, a back plate 15, a spacer 16, a diaphragm 17, a diaphragm plate 18, and a cover 19.

  The casing 12 is made of an electrical insulator such as epoxy resin, liquid crystal polymer, and ceramic, and forms a skeleton of the condenser microphone 10 and has a substantially cylindrical hole portion 22 for forming an air chamber 23. Yes. As shown in part in FIG. 5, conductive patterns 13a and 13b for grounding are provided on the upper surface and the lower surface of the housing 12, respectively. In addition, a conductive pattern 13 c that connects the conductive patterns 13 a and 13 b is provided on the side surface of the housing 12. On the circuit board 13, an impedance conversion circuit including a field effect transistor 20, a capacitor 21 and the like is configured. Although not shown, the circuit board 13 is provided with an electrical configuration such as an electrode pattern and a through hole. The circuit board 13 is bonded and fixed to the lower surface of the housing 12 in FIG. 1, and the impedance conversion circuit is disposed in each hole 22. The contact spring 14 is disposed on the circuit board 13 in the hole 22. The contact spring 14 is integrally formed of a stainless steel plate and includes a substantially annular plate-like support portion 14a and three leg portions 14b extending obliquely outward from the support portion 14a downward. Each leg portion 14b abuts on a land (not shown) on the circuit board 13, and is electrically connected to the gate side of the field effect transistor 20 through the land. The back plate 15 is supported on the upper surface of the support portion 14a.

  The back plate 15 has a disk shape with an outer diameter slightly smaller than the inner diameter of the hole portion 22 of the housing 12, and is held in the hole portion 22 so as to be movable up and down. The back plate 15 includes a plate body 15a made of a stainless steel plate, and an electret layer 15b made of a film such as FEP (Fluorinated Ethylene Propylene) is provided on the upper surface of the plate body 15a. The electret layer 15b has been subjected to polarization treatment by corona discharge or the like. Further, the back plate 15 includes a plurality of through holes 15c. The plate body 15 a is connected to the gate of the field effect transistor 20 through the contact spring 14. The spacer 16 is bonded and fixed to the upper surface of the housing 12. The spacer 16 has a hole 16 a having an inner diameter smaller than the inner diameter of the hole 22 of the housing 12, and the upper surface of the outer peripheral edge of the back plate 15 is in contact with the lower surface of the edge of the hole 16 a. The contact spring 14 is sandwiched between the circuit board 13 and the back plate 15 in an elastically deformed state. On the other hand, the back plate 15 is elastically pressed against the lower surface of the inner peripheral edge of the spacer 16 by the elastic biasing force of the contact spring 14. The spacer 16 is made of a resin film such as PET (PolyEthylene Terephthalate) or a metal plate such as stainless steel.

  The diaphragm 17 is bonded and fixed to the upper surface of the spacer 16. The circuit chamber 13, the housing 12, the spacer 16, and the diaphragm 17 form the air chamber (shown in FIG. 2) partitioned from the outside. The diaphragm plate 18 is bonded and fixed to the upper surface of the diaphragm 17. The diaphragm plate 18 has a hole 18 a having an inner diameter substantially the same as the hole 16 a of the spacer 16. The diaphragm 17 is sandwiched between the spacer 16 and the diaphragm plate 18 at portions excluding the holes 18a, and the spacer 16 sets a distance from the diaphragm 17 to a predetermined value. That is, the back plate 15 and the diaphragm 17 constitute a capacitor having a predetermined impedance. The diaphragm 17 can vibrate a portion of the diaphragm plate 18 in the hole 18a. The cover 19 is bonded and fixed to the upper surface of the diaphragm plate 18. The cover 19 includes a sound hole 19 a that covers the diaphragm 17 from the outside in the hole 18 a of the diaphragm plate 18 and communicates the outside with the diaphragm 17.

  The spacer 16, the diaphragm 17 and the diaphragm plate 18 have through holes 16b, 17a and 18b communicating with each other. As shown in FIG. 5, the diaphragm plate 18 has a housing 12 in contact with the conductive portion 25 via a conductive portion 25 made of a conductive adhesive or the like filled in each of the through holes 18b, 17a, and 16b. The conductive pattern 13a is electrically connected. Further, the diaphragm plate 18 is electrically connected to the ground on the circuit board 13 through the conductive patterns 13a, 13c, and 13b.

  In the condenser microphone 10 configured as described above, the diaphragm 17 vibrates through the sound hole 19a of the cover 19 due to the sound wave from the sound source. At this time, as the diaphragm 17 vibrates, the air freely moves between the upper side and the lower side of the back plate 15 through the through hole 15c, so that the diaphragm 17 is allowed to vibrate. Then, the distance between the diaphragm 17 and the back plate 15 changes from the set value, and the impedance of the capacitor changes according to the frequency, amplitude and waveform of the sound. This change in impedance is converted into a voltage signal by an impedance conversion circuit and output.

Next, a method for manufacturing the condenser microphone 10 will be described.
In this manufacturing method, as shown in FIG. 4, a housing forming member 30, a circuit board forming member 31, a spacer forming member 32, a diaphragm sheet 33, a diaphragm plate forming member 34, a cover forming member 35, a back plate 15 and contacts. A plurality of condenser microphones 10 are manufactured using springs 14 and the like.

  The housing forming member 30 is a plate material for forming a plurality of the housings 12, and a plurality of the hole portions 22 are formed at a predetermined pitch vertically and horizontally. The housing forming member 30 is formed with a plurality of holes 30 a, long holes 30 b, and long holes 30 c at a predetermined pitch so as to be positioned around each hole 22. The hole 30a is a through hole, and a part of the hole 30a becomes the conductive pattern 13c. The holes 30a and the long holes 30b and 30c are through holes, and are provided at positions to be cut by dicing described later. The circuit board forming member 31 is an insulating board for forming a plurality of the circuit boards 13, and a plurality of the impedance conversion circuits are formed at predetermined pitches in the vertical and horizontal directions. The circuit board forming member 31 is provided with a hole 31a having the same diameter at each position corresponding to the hole 30a of the housing forming member 30. The spacer forming member 32 is a sheet material for forming a plurality of the spacers 16, and a plurality of the holes 16 a are formed at a predetermined pitch vertically and horizontally. As shown in FIG. 6, the spacer forming member 32 has a plurality of through holes 32a, 32b, and 32c that divide each spacer 16, and the adjacent spacers 16 are connected to each other via a bridging portion 32d. I have. The through holes 32a, 32b, and 32c are provided at positions corresponding to the holes 30a, 30b, and 30c of the housing forming member 30, respectively. The diaphragm sheet 33 is a sheet material for forming a plurality of the diaphragms 17. Further, the diaphragm sheet 33 is provided with holes 33a having the same diameter at each position corresponding to each hole 30a of the housing forming member 30. The diaphragm plate forming member 34 is a sheet material for forming a plurality of the diaphragm plates 18, and a plurality of the holes 18a are formed at a predetermined pitch vertically and horizontally. The diaphragm plate forming member 34 is provided with holes 34a having the same diameter for each position corresponding to each hole 33a of the diaphragm sheet 33.

  In order to manufacture the condenser microphone 10, first, the spacer forming member 32 and the diaphragm plate forming member 34 are stacked with the diaphragm sheet 33 interposed therebetween, and the three stacked members are integrated by bonding, and this is combined with the diaphragm assembly. To do. At this time, the tension of the diaphragm sheet 33 is appropriately set between the hole 16a of the spacer forming member 32 and 18a of the diaphragm plate forming member 34. On the other hand, the circuit board forming member 31 is bonded to the housing forming member 30 to integrate them, and this is used as the housing assembly. Next, the contact spring 14 and the back plate 15 are assembled in this order into the hole 22 of the housing forming member 30 in the housing assembly. Next, the diaphragm assembly is bonded to the upper surface of the casing assembly to integrate them, and this is used as a microphone assembly. Next, the cover forming member 35 is bonded to the upper surface of the microphone assembly to integrate them. As shown in FIG. 7, the laminated body 40 formed in this way is composed of a plurality of the condenser microphone constituting bodies 11. Finally, as shown in FIG. 8, the laminated body 40 is diced (cut) with a diamond blade, and each condenser microphone constituting body 11 is separated into a condenser microphone 10. At this time, in the thickest casing forming member 30 made of epoxy resin, liquid crystal polymer, ceramic, or the like, it is cut at the portions of the holes 30a and the long holes 30b, 30c arranged in parallel around the hole portion 22, Cutting resistance in dicing is reduced. Moreover, since the spacer formation member 32 which consists of resin films, such as PET, or metal plates, such as stainless steel, is cut | disconnected in the part of each through-hole 32a-32c, cutting resistance is further reduced.

  For convenience of explanation, FIG. 4, FIG. 7 and FIG. 8 show a state in which 3 × 4 = 12 condenser microphone constituent bodies 11 are formed. A body 11 is formed.

  In this embodiment, the conductive portion 25 is formed by filling each through hole 18b, 17a, 16b with a conductive adhesive. However, each through hole 18b, 17a, 16b is internally provided with a metal pin or a spring. You may comprise by doing.

  Therefore, according to the method for manufacturing the condenser microphone 10 of this embodiment, the circuit board forming member 31, the housing forming member 30, the spacer forming member 32, the diaphragm sheet 33, and the diaphragm plate forming member 34 are laminated in this order. Further, by arranging the back plate 15 and the contact spring 14 in the air chamber 23 formed by each forming member, a laminated body 40 including a plurality of condenser microphone constituent bodies 11 is formed. The laminated body 40 is diced to separate the condenser microphone constituent bodies 11, and the condenser microphone constituent bodies 11 are used as the condenser microphones 10. For this reason, productivity improves compared with the conventional manufacturing method which manufactures a condenser microphone one by one.

  Further, in the air chamber 23 of each condenser microphone constituting body 11, the back plate 15 is held in contact with the spacer 16 by being elastically biased by the contact spring 14. For this reason, when heat is applied to the condenser microphone 10 housed in the metal shield case due to reflow soldering or the like, the force applied to the condenser microphone 10 from the shield case due to the difference in thermal expansion coefficient is a contact spring. 14 is absorbed by the elastic deformation 14 and does not join the spacer 16. Therefore, the spacer 16 is not deformed and its thickness is not reduced, and the distance between the back plate 15 and the spacer 16 is not reduced from the set value, so that the sensitivity characteristic is not deteriorated.

  The spacer forming member 32 has a plurality of through holes 32 a to 32 c that partition the spacers 16, and is cut at the portions of the through holes 32 a to 32 c when the stacked body 40 is diced. Therefore, the cutting resistance at the time of dicing of the laminated body 40 is reduced and the dicing becomes easy, so that the productivity of the condenser microphone 10 is further improved.

  The thickest casing forming member 30 has a plurality of holes 30 a to 30 c around the hole portion 22, and is cut at each hole 30 a to 30 c when the laminated body 40 is diced. Therefore, the cutting resistance at the time of dicing of the laminated body 40 is reduced and the dicing becomes easy, so that the productivity of the condenser microphone 10 is further improved.

  Further, the through holes 32 a to 32 c of the spacer forming member 32 and the holes 30 a to 30 c of the housing forming member 30 are provided at positions corresponding to each other in the stacked body 40. For this reason, since the dicing of the laminate 40 is further facilitated, the productivity is further improved.

  Further, after the diaphragm sheet 33 is sandwiched and laminated between the spacer forming member 32 and the diaphragm plate forming member 34, the diaphragm assembly and the housing forming member 30 are bonded and integrated. For this reason, it is easier to adjust the tension of the diaphragm sheet 33 than when these members are laminated and integrated at a time. Therefore, the condenser microphone 10 can be manufactured more easily.

  Further, by forming all of the housing 12, the circuit board 13, the spacer 16, the diaphragm plate 18, and the cover 19 from a metal member other than an epoxy resin, a liquid crystal polymer, or a ceramic, the cutting resistance when the laminated body 40 is diced can be reduced. Is reduced, dicing is facilitated, and productivity is further improved.

In addition, this embodiment can also be changed and embodied as follows.
When the condenser microphone 10 is manufactured, the microphone assembly without the cover forming member 35 is diced to obtain the condenser microphone 10 without the cover 19. Next, the cover 19 is adhered and fixed to the condenser microphone 10 to complete.

  As shown in FIG. 9, a condenser microphone is configured using a back plate 15 having a substantially bowl shape in plan view and a housing 12 having a substantially bowl-shaped hole 22. In this case, the contact spring 14 is composed of a substantially rectangular support portion 14a and four leg portions 14b provided at the four corners of the support portion 14a.

  The present invention is embodied in a foil electret type electret condenser microphone in which the diaphragm 17 has an electret function instead of the back plate 15.

  The present invention is embodied in a charge pump type condenser microphone in which neither the electret function is given to the back plate 15 and the diaphragm 17 but the voltage is applied to the back plate 15 and the diaphragm 17 by the charge pump circuit.

The technical idea that can be grasped from the embodiment will be described below.
A housing forming member having a plurality of holes for forming air chambers, a circuit board forming member provided with a plurality of impedance conversion circuits corresponding to each air chamber, and a plurality of spacers corresponding to each air chamber Using a spacer forming member for forming a plurality of diaphragm sheets corresponding to each spacer, and a diaphragm plate forming member for forming a plurality of diaphragm plates corresponding to each diaphragm, A circuit board forming member, a housing forming member, a spacer forming member, a diaphragm sheet, and a diaphragm plate forming member are laminated, and a back plate and the back plate are elastically biased for each of the air chambers formed by the lamination. Holding the spacer in contact with the spacer forming member and And a contact spring that is electrically connected to each other, and the laminated members are joined together to form a laminated body composed of a plurality of condenser microphone constituting bodies, and then the laminated body is cut to obtain each condenser microphone constituting body. A condenser microphone formed by separating.

The perspective view which shows the condenser microphone of one Embodiment. The longitudinal cross-sectional view which shows a condenser microphone. Similarly disassembled perspective view. The perspective view which shows the member used for manufacture of a condenser microphone. The partial longitudinal cross-sectional view of the capacitor | condenser microphone which shows a through hole. The top view which shows a part of spacer formation member. The perspective view which shows a 2nd microphone assembly. The perspective view which shows the 2nd microphone assembly after dicing. The partially exploded perspective view in the condenser microphone of other embodiments.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Condenser microphone array, 11 ... Condenser microphone structure, 12 ... Housing, 13 ... Circuit board, 14 ... Contact spring, 15 ... Back plate, 16 ... Spacer, 16b ... Through hole, 17 ... Diaphragm, 17a ... Through hole , 18 ... Diaphragm plate, 18b ... Through hole, 19 ... Cover, 20 ... Field effect transistor constituting impedance conversion circuit, 21 ... Similarly capacitor, 22 ... Hole, 23 ... Air chamber, 30 ... Housing forming member, 30a ... holes as through holes, 30b, 30c ... same long holes, 31 ... circuit board forming members, 32 ... spacer forming members, 32a to 32c ... through holes, 32d ... bridge portions, 33 ... diaphragm sheets, 34 ... diaphragm plate formation Member, 35 ... cover forming member, 40 ... laminate.

Claims (7)

A housing forming member having a plurality of holes each for forming an air chamber;
A circuit board forming member provided with a plurality of impedance conversion circuits corresponding to each air chamber;
A spacer forming member for forming a plurality of spacers corresponding to each air chamber;
A diaphragm sheet for forming a plurality of diaphragms corresponding to each spacer;
Using a diaphragm plate forming member for forming a plurality of diaphragm plates corresponding to each diaphragm,
The circuit board forming member, the housing forming member, the spacer forming member, the diaphragm sheet and the diaphragm plate forming member are laminated, and a back plate and an elastic biasing of the back plate are provided for each of the air chambers formed by the lamination. Then, a contact spring that is held in contact with the spacer forming member and is electrically connected to the impedance conversion circuit is disposed, and the laminated members are integrally joined to form a plurality of condenser microphone components. A method of manufacturing a condenser microphone, comprising: forming a multilayer body, and then cutting the multilayer body to separate each capacitor microphone component.   2. The condenser microphone according to claim 1, wherein the spacer forming member has a plurality of through holes that divide the spacer, and is cut at the through holes when the laminated body is cut. Method.   3. The condenser microphone according to claim 2, wherein the casing forming member has a plurality of through holes around the hole portion, and is cut at a portion of each through hole when the laminated body is cut. Manufacturing method.   4. The method of manufacturing a condenser microphone according to claim 3, wherein the through hole of the spacer forming member and the through hole of the housing forming member are provided at positions corresponding to each other in the laminated body.   The diaphragm plate forming member, the diaphragm sheet, and the spacer forming member are provided with through holes communicating with each other, and the diaphragm plate forming member and the impedance conversion circuit are electrically connected to each other through the through holes. The manufacturing method of the capacitor | condenser microphone as described in any one of Claims 1-4.   The diaphragm assembly and the casing forming member are integrated after the spacer forming member, the diaphragm sheet, and the diaphragm plate forming member are laminated and integrated. A method for manufacturing a condenser microphone according to one item.   A cover forming member for forming a cover that covers the diaphragm is further laminated and integrated on the diaphragm plate forming member side of the laminate, and then the laminate is cut. Item 7. A method for manufacturing a condenser microphone according to any one of Items 6 to 6.

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