JP2011120097A - Microphone unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high quality microphone unit capable of attaining thinning while suppressing deterioration of microphone characteristics. <P>SOLUTION: A microphone unit 1 includes: an electric/acoustic converting section 12 having a diaphragm 122, that is displaced by sound pressure, for converting a sound signal into an electric signal; and a packaging member 11 on which the electric/acoustic converting section 12 is packaged. On a packaging surface 11a of the packaging member 11 to package the electric/acoustic converting section 12 a first opening 21 and a second opening 22 are included. The electric/acoustic converting section 12 is packaged on the packaging member such that surfaces 122a, 122b of the diaphragm 122 to apply sound pressure thereto become substantially parallel with the packaging surface 11a and the first opening 21 is covered. The packaging member 11 includes an internal space 23 communicating the first opening 21 and the second opening 22 and in the internal space 23, there is provided a supporting part 14 held between two confronted inner walls 23a and 23b which are substantially in parallel with the packaging surface 11a. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a microphone unit having a function of converting input sound into an electric signal and outputting the electric signal.

  Conventionally, for example, a microphone unit is applied to a voice input device such as a voice communication device such as a mobile phone or a transceiver, an information processing system using a technique for analyzing input voice such as a voice authentication system, or a recording device. Yes.

  In recent years, electronic devices have been miniaturized, and a microphone unit applied to an audio input device is also desired to be small and thin. Further, it is preferable to pick up only the target voice (user's voice) during telephone calls, voice recognition, and voice recording. For this reason, it is desirable that the performance of the microphone unit be such that the target voice can be accurately extracted and noise (background noise, etc.) other than the target voice can be removed.

  Under the background as described above, the present applicants are formed so that sound pressure is applied from both surfaces of the diaphragm, and are small-sized to convert a sound signal into an electrical signal based on vibration of the diaphragm based on the sound pressure difference. Development of a microphone unit (hereinafter sometimes referred to as a differential microphone unit) is underway (see, for example, Patent Documents 1 and 2).

  In the differential microphone unit disclosed in Patent Documents 1 and 2, user voices that are generated near the microphone unit and are incident on both sides of the diaphragm are louder on one side and the other side of the diaphragm. A pressure difference is generated to vibrate the diaphragm. On the other hand, noises incident on both surfaces of the diaphragm from a distance become almost the same sound pressure and cancel each other out so that the diaphragm hardly vibrates. Therefore, the sound pressure that vibrates the diaphragm can be regarded as the sound pressure indicating the user voice, and the electric signal obtained based on the vibration of the diaphragm is an electric signal indicating the user voice from which noise has been removed. It can be considered as a signal. That is, according to the differential microphone unit disclosed in Patent Documents 1 and 2, only the target sound from which noise has been removed can be converted into an electrical signal and output.

JP 2008-258904 A JP 2009-135777 A

  By the way, the present applicants have improved the differential microphone unit as shown in Patent Documents 1 and 2, and have developed a microphone unit 100 that can be made thin as shown in FIG. 8, for example. A microphone unit 100 shown in FIG. 8 includes a microphone substrate 101 and a MEMS (Micro Electro Mechanical System) chip 102 that has a diaphragm 103 that is displaced by sound pressure and converts sound signals into electric signals.

  A first opening 104 and a second opening 105 are provided on the upper surface 101 a of the microphone substrate 101. The first opening 104 and the second opening 105 communicate with each other through a substrate internal space 106 provided inside the microphone substrate 101. The MEMS chip 102 is disposed so as to cover the first opening 104.

  By configuring the microphone unit 100 in this way, sound pressure is applied to the diaphragm 103 of the MEMS chip 102 from the upper surface 103a side and the lower surface 103b side, and the diaphragm 103 is caused by the difference in sound pressure applied to the both surfaces 103a and 103b. Vibrates. Note that sound pressure is applied to the lower surface 103 a of the diaphragm 103 by the sound wave passing through the second opening 105, the substrate internal space 106, and the first opening 104 in this order to the diaphragm 103.

  In the newly developed microphone unit 100, the diaphragm 103 and the microphone substrate 101 are arranged so as to be substantially parallel, and the substrate internal space 106 provided in the microphone substrate 10 is used as a sound path. In addition, the differential microphone unit can be thinned. However, it has been found that the newly developed microphone unit 100 has the following problems.

  That is, when the microphone substrate 101 is thinned due to a demand for thinning the microphone unit 100, the substantial thickness of the portion where the substrate internal space 106 is provided becomes very thin (for example, about 0.2 mm thick). Becomes easy to bend. Then, the substrate internal space 106 may become narrow due to this bending. As described above, the substrate internal space 106 is used as a sound path. When the substrate internal space 106 becomes narrow, the acoustic resistance increases, and as a result, the microphone characteristics may be deteriorated.

  Further, when the MEMS chip 102 is die-bonded on the microphone substrate 101 or when wire bonding is performed for wiring formation, a force is applied to press the MEMS chip 102 toward the microphone substrate 101. When the thin microphone substrate 101 is used, the portion in which the substrate internal space 106 is provided is likely to be bent by such a force, which may cause die bonding failure or wire connection failure. In addition, the substrate internal space 106 is narrowed due to the bending generated by die bonding or wire bonding, which may cause deterioration of the microphone characteristics. In addition, when the microphonin unit 100 is mounted on the mounting substrate of the voice input device, force is applied to the microphone substrate 101, and the substrate internal space 106 similar to the above is narrowed, which may cause deterioration of the microphone characteristics. .

  In view of the above points, an object of the present invention is to provide a high-quality microphone unit that can be reduced in thickness while suppressing deterioration of microphone characteristics.

  In order to achieve the above object, a microphone unit of the present invention includes an electroacoustic conversion unit that has a diaphragm that is displaced by sound pressure and converts a sound signal into an electric signal, and a mounting member on which the electroacoustic conversion unit is mounted. A mounting surface on which the electroacoustic conversion unit of the mounting member is mounted is provided with a first opening and a second opening, and the electroacoustic conversion unit is The surface on which the sound pressure of the diaphragm is applied and the mounting surface are substantially parallel and are mounted on the mounting member so as to cover the first opening. The mounting member includes the first opening and the first mounting surface. An internal space that communicates with the two openings is provided, and a support portion that is sandwiched between two opposing inner walls that are substantially parallel to the mounting surface is provided in the internal space.

  According to this configuration, it is possible to apply sound pressure from both surfaces of the diaphragm included in the electroacoustic conversion unit, and a differential microphone unit can be obtained. The surface to which the sound pressure of the diaphragm is applied and the mounting surface of the mounting member on which the electroacoustic conversion unit is mounted (the above-described microphone substrate is an example of this mounting member) are substantially parallel to the mounting member. Since the internal space provided is used as a sound path, the differential microphone unit can be thinned. In addition, since the internal space formed in the mounting member is provided with a support portion sandwiched between two opposing inner walls substantially parallel to the mounting surface on which the electroacoustic conversion unit is mounted, the thickness of the mounting member Even when the thickness of the mounting member is reduced, the bending of the mounting member can be suppressed. That is, according to this configuration, it is possible to suppress the narrowing of the internal space due to the bending of the mounting member, and it is possible to reduce the thickness of the microphone unit while suppressing the deterioration of the microphone characteristics.

  In the microphone unit having the above configuration, it is preferable that the support portion is provided so as to overlap the electroacoustic conversion portion in plan view in a direction substantially orthogonal to the mounting surface.

  According to this configuration, since the support portion is provided in the vicinity of a portion where force is easily applied to the mounting member when the microphone unit is manufactured, the internal space is prevented from being narrowed due to the bending of the mounting member during manufacturing. It's easy to do.

  In the microphone unit configured as described above, the mounting member may be composed of a plurality of members. In this way, it is easy to form a mounting member having an internal space. In this case, the mounting member may be formed from a plurality of types of members, for example, the mounting member is formed by combining a substrate and a resin.

  The mounting member may be formed by bonding a plurality of substrates. And in this structure, it is preferable that the said support part is integrally formed in one of the said several board | substrates. When the microphone unit is made thin, the internal space formed in the mounting member becomes very thin. Therefore, it is better to provide the support part integrally with the substrate than to provide the support part as a separate member from the substrate. The microphone unit can be easily manufactured.

  The microphone unit having the above-described configuration further includes a lid provided with a first space and a second space separated from the first space, and the lid has the first space formed by the electroacoustic transducer. The diaphragm is mounted on the mounting member so that the second space communicates with the internal space through the second opening, and one surface of the diaphragm is formed on the first space and the lid. The other surface of the diaphragm is connected to the first opening, the internal space, the second opening, the second space, and the lid. It is good also as communicating with the exterior via the 2nd sound hole provided in a body.

  According to this configuration, it is possible to reduce the thickness of the differential microphone unit having the lid while suppressing the deterioration of the microphone characteristics.

  According to the present invention, it is possible to provide a high-quality microphone unit that can be reduced in thickness while suppressing deterioration of microphone characteristics.

Schematic which shows the structure of the microphone unit of this embodiment. Schematic plan view when two substrates constituting the mounting member included in the microphone unit of this embodiment are viewed from above Schematic sectional view showing the configuration of a MEMS chip provided in the microphone unit of the present embodiment Schematic plan view for explaining another form of the support portion provided in the internal space Schematic plan view for explaining another form of the support portion provided in the internal space The figure which shows the structural example of the resin molding member in the case of comprising a mounting member using a board | substrate and a resin molding member. The figure which shows the modification of the microphone unit of this embodiment, and is a figure which shows a structure in case a microphone unit is provided with a cover body Schematic sectional view showing the configuration of a differential microphone unit developed previously by the present applicant

  Hereinafter, embodiments of a microphone unit to which the present invention is applied will be described in detail with reference to the drawings.

  First, the configuration of the microphone unit of the present embodiment will be described.

  FIG. 1 is a schematic diagram illustrating a configuration of a microphone unit according to the present embodiment, in which an upper part is a schematic sectional view and a lower part is a schematic plan view when the microphone unit is viewed from above. As shown in FIG. 1, the microphone unit 1 of this embodiment includes a mounting member 11, a MEMS (Micro Electro Mechanical System) chip 12 having a diaphragm 122, and an ASIC (Application Specific Integrated Circuit) 13. Yes. The MEMS chip is an embodiment of the electroacoustic conversion unit of the present invention.

  The mounting member 11 is a member on which the MEMS chip 12 and the ASIC 13 are mounted. In the present embodiment, the mounting member 11 is formed by bonding two substrates (members), and the mounting member 11 corresponds to the microphone substrate 101 shown in FIG. FIG. 2 is a schematic plan view when two substrates constituting the mounting member included in the microphone unit of the present embodiment are viewed from above, and FIG. 2A is a diagram of the first substrate disposed on the upper side. It is a figure of the 2nd board | substrate arrange | positioned 2 (b) below.

  The first substrate 111 and the second substrate 112 constituting the mounting member 11 may be formed using a substrate made of a known substrate material, and the material is not particularly limited. However, those that can be obtained at low cost and that have high rigidity are preferable. For example, FR-4, BT resin (registered trademark), or the like is preferably used. Further, the first substrate 111 and the second substrate 112 may be substrates made of different materials, but are preferably made of the same material having the same linear expansion coefficient.

  As shown in FIG. 2A, the first substrate 111 constituting the mounting member 11 is formed with two through holes, a first through hole 111a and a second through hole 111b. In the microphone unit 1 of the present embodiment, the through hole 111a has a substantially circular shape in a plan view, and the through hole 111b has a substantially rectangular shape in a plan view. You may change the shape.

  As shown in FIG. 2B, a groove 112a having a substantially rectangular shape in plan view is formed in the second substrate 112 constituting the mounting member 11. The groove 112a is provided at a position so as to overlap the first through hole 111a and the second through hole 111b when the first substrate 111 and the second substrate 112 are bonded together.

  Further, in the groove 112a formed in the second substrate 112, two support portions 14 having a height substantially the same as the depth of the groove 112a are provided. Both of these two support portions 14 are provided so as to protrude with respect to the side wall of the groove 112a. The two support portions 14 are provided so as to face each other along the width direction W.

  In the present embodiment, the support portion 14 is formed integrally with the second substrate 112. For example, the groove 112a and the support portion 14 (two) can be formed by scraping the hatched portion in FIG. 2B of the second substrate 112 to a predetermined depth with a router. However, the support portion 14 may be a separate member from the substrate constituting the mounting member 11, and may be formed by, for example, bonding an epoxy resin or the like to the bottom surface of the groove 112a.

  The first substrate 111 and the second substrate 112 are bonded together by, for example, an epoxy resin adhesive, an epoxy resin adhesive sheet, or the like. As a result, as shown in FIG. 1, the first opening 21 and the second opening 22 are provided in the mounting surface 11 a, and an internal space that communicates the first opening 21 and the second opening 22 ( The mounting member 11 provided with the substrate internal space 23 is obtained.

  When the first substrate 111 and the second substrate 112 are bonded together, the two support portions 14 come into contact with the lower surface of the first substrate 111. In other words, in the microphone unit 1, the two support portions 14 are sandwiched between the upper wall 23 a and the lower wall 23 b (two inner walls facing each other substantially parallel to the mounting surface 11 a) of the internal space 23 of the mounting member 11. Is provided.

  In the microphone unit 1 of the present embodiment, the first substrate 111 and the second substrate are arranged so that the entire two through holes 111a and 111b overlap the groove 112a in plan view in a direction substantially orthogonal to the mounting surface 11a. 112 is configured. Further, the support portion 14 is provided so as to overlap the MEMS chip 12 in plan view in a direction substantially orthogonal to the mounting surface 11a.

  In addition, although not shown, the first substrate 111 and the second substrate 112 are formed with various wirings necessary for exhibiting the function of the microphone unit 1 (the function of converting the input sound into an electrical signal and outputting it). Has been. On the lower surface 11a of the mounting member 11 (more specifically, the lower surface of the second substrate 112), electrodes 15 that are electrically connected to these wirings are provided. The electrode 15 is used when the microphone unit 1 is surface-mounted on a mounting substrate of a voice input device (for example, a mobile phone), thereby supplying power to the microphone unit 1 and voice input from the microphone unit 1. The signal can be output to the device.

  FIG. 3 is a schematic cross-sectional view showing the configuration of the MEMS chip provided in the microphone unit of the present embodiment. As shown in FIG. 3, the MEMS chip 12 made of a silicon chip includes an insulating base substrate 121, a diaphragm 122, an insulating layer 123, and a fixed electrode 124, and constitutes a condenser microphone. ing.

  The base substrate 121 has an opening 121a having a substantially circular shape in plan view. The diaphragm 122 provided on the base substrate 121 is a thin film that vibrates (vibrates in the vertical direction) by receiving sound pressure, and has conductivity and forms one end of an electrode. The fixed electrode 124 is disposed so as to face the diaphragm 122 with the insulating layer 123 interposed therebetween. Thereby, a capacitance is formed between the diaphragm 122 and the fixed electrode 124. The fixed electrode 124 is formed with a plurality of sound holes 124a so that sound waves can pass through.

  The MEMS chip 12 is configured such that sound pressure is applied from the upper surface 122 a and the lower surface 122 b of the diaphragm 122. For this reason, the diaphragm 122 vibrates according to the difference between the sound pressure pf applied from the upper surface 122a and the sound pressure pb applied from the lower surface 122b. When the diaphragm 123 vibrates, the gap Gp between the diaphragm 122 and the fixed electrode 124 changes, and the electrostatic capacitance between the diaphragm 122 and the fixed electrode 124 changes. As a result, the sound wave (sound signal) incident on the MEMS chip 12 can be extracted as an electric signal.

  Note that the configuration of the MEMS chip as the electroacoustic conversion unit is not limited to the configuration of the present embodiment. For example, in the present embodiment, the diaphragm 122 is below the fixed electrode 124, but is configured to have an opposite relationship (relationship in which the diaphragm is on and the fixed electrode is on the bottom). It doesn't matter.

  In the microphone unit 1, the MEMS chip 12 is mounted on the mounting member 11 such that the upper surface 122 a and the lower surface 122 b of the diaphragm 122 are substantially parallel to the mounting surface 11 a of the mounting member 11 and cover the first opening 21. (See FIG. 1). Note that the MEMS chip 12 is mounted by wire bonding in this embodiment. Specifically, the bottom surface of the MEMS chip 12 that faces the mounting surface 11 a of the mounting member 11 is joined by a die bond material (for example, an epoxy resin-based or silicone resin-based adhesive) 16. By joining in this way, the sound does not leak from a gap formed between the mounting surface 11a of the mounting member 11 and the lower surface of the MEMS chip 12. Further, the MEMS chip 12 is electrically connected to the ASIC 13 by a wire 17.

  The ASIC 13 mounted on the mounting surface 11 a of the mounting member 11 is an integrated circuit that amplifies an electrical signal that is extracted based on a change in capacitance of the MEMS chip 12. The ASIC 13 functioning as the signal processing unit may include a charge pump circuit and an operational amplifier so that a change in capacitance in the MEMS chip 12 can be accurately acquired.

  The bottom surface of the ASIC 13 that faces the mounting surface 11 a of the mounting member 11 is bonded by a die bonding material 18. The electric signal amplified by the ASIC 13 is electrically connected to an electrode formed on the mounting surface 11 a of the mounting member 11 by a wire 19. Then, the electric signal amplified by the ASIC 13 can be output to the outside of the microphone unit 1 through wiring (including through wiring) formed on the first substrate 111 and the second substrate 112 constituting the mounting member 11. ing.

  In the above description, the MEMS chip 12 and the ASIC 13 are mounted by wire bonding, but the MEMS 12 and the ASIC 13 may of course be flip-chip mounted. When flip chip mounting is performed, the MEMS chip 12 is, for example, a frame-shaped connection pad (not shown) formed so as to surround the first opening 21 of the mounting surface 11a, and its lower surface (lower surface of the MEMS chip 12). Are joined by solder or the like, for example. This prevents sound from leaking from a gap formed between the mounting surface 11a of the mounting member 11 and the lower surface of the MEMS chip 12. Further, the MEMS chip 12 and the ASIC 13 are electrically connected by a wiring formed inside the mounting member 11.

  Next, the effect of the microphone unit 1 configured as described above will be described.

  In the microphone unit 1, sound waves that have passed through the sound holes 124 a of the fixed electrode 124 from the upper side of the MEMS chip 12 are applied to the upper surface 122 a of the diaphragm 122 as sound pressure. On the other hand, a sound wave input from the second opening 22 and passing through the inner space 23 and the first opening 21 in this order is applied to the lower surface 122b of the diaphragm 122 as a sound pressure.

  The sound pressure of sound waves (the amplitude of sound waves) is inversely proportional to the distance from the sound source. The sound pressure attenuates rapidly at a position close to the sound source, and gradually decreases as the distance from the sound source increases. For this reason, in the case of the configuration of the present embodiment, the user sound that is generated near the microphone unit 1 and is incident on the both surfaces 122a and 122b of the diaphragm 122 is loudly generated on the upper surface 122a and the lower surface 122b of the diaphragm 122. A pressure difference is generated to vibrate the diaphragm. On the other hand, noise incident on both surfaces 122a and 122b of the diaphragm 122 from a distance becomes almost the same sound pressure, so that they cancel each other and hardly vibrate the diaphragm.

  For this reason, the sound pressure that vibrates the diaphragm 122 can be regarded as the sound pressure indicating the user voice, and the electric signal obtained based on the vibration of the diaphragm 122 is the user voice from which noise is removed. It can be considered that the electrical signal is shown. That is, the microphone unit 1 of the present embodiment can convert only the target sound from which noise has been removed into an electrical signal and output it, and can be said to be a high-quality microphone unit.

  Further, in the microphone unit 1 of the present embodiment, the surfaces 122a and 122b to which the sound pressure of the diaphragm 122 is applied and the mounting surface 11a on which the MEMS chip 12 is mounted are substantially parallel to each other, and the inside provided in the mounting member 11 The space 23 is used as a sound path. For this reason, it is possible to reduce the thickness of the microphone unit that is surface-mounted on a mounting substrate of a voice input device (for example, a mobile phone).

  Furthermore, in the microphone unit 1 of the present embodiment, the support portion 14 that is sandwiched between the upper wall 23a and the lower wall 23b of the internal space 23 is provided in the internal space 23 that is used as the above-described sound path. For this reason, even when the first substrate 111 constituting the mounting member 11 is thin (for example, about 0.2 mm), the support portion 14 can suppress the bending of the first substrate 111.

  When the microphone unit 1 is manufactured, for example, when the MEMS chip 12 is mounted on the mounting member 11 or when wire bonding is performed, a large force may be applied from the MEMS chip 12 to the mounting member 11. In the microphone unit 1 of the present embodiment, even when such a force is applied, the support portion 14 can suppress the bending of the first substrate 111.

  That is, according to the microphone unit 1 of the present embodiment, it is possible to prevent the internal space 23 formed in the mounting member 11 from being narrowed due to the bending generated in a part of the mounting member 11, thereby preventing defects in die bonding and wire bonding. Can be suppressed. Therefore, according to the microphone unit 1 of the present embodiment, it is possible to reduce the thickness of the microphone unit while suppressing deterioration of the microphone characteristics.

  The microphone unit 1 described above shows an example of the embodiment of the present invention, and the scope of application of the present invention is not limited to the above-described embodiment. That is, various modifications may be made to the above-described embodiment without departing from the object of the present invention.

  For example, in the embodiment described above, the two support portions 14 are provided in the internal space 23 formed in the mounting member 11. However, the number, shape, and arrangement of the support portions 14 are the same as those of the present embodiment. It is not limited to this configuration, and it may be changed as appropriate. The support part 14 should just be arrange | positioned so that the internal space 23 may become narrow by the deformation | transformation of the mounting member 11. FIG. That is, for example, as shown in FIG. 4, the support portions 14 may be arranged at four locations. FIG. 4 is a schematic plan view for explaining another form of the support portion provided in the internal space, and is a view similar to the lower view of FIG.

  Further, unlike the embodiment described above, for example, as shown in FIG. 5A, the support portion 14 is formed at a position away from two side walls facing the width direction W of the groove 112a. I do not care. 5A, the groove 112a has a configuration in which two rows of support portions 14 each having a substantially rectangular shape in plan view arranged in the width direction W are provided in two rows. Further, for example, as shown in FIG. 5B, the size of the support portion 14 is made larger than that in the embodiment shown above, and the width of the groove 112a becomes narrow in the portion corresponding to the lower portion of the MEMS chip 12. The support portion 14 may be provided so as to be wide at a portion corresponding to the lower portion of the second opening 22. According to this configuration, the expectation of the following effects can be increased while ensuring the wide cross-sectional area of the sound path from the lower part of the MEMS chip 12 to the lower part of the second opening 22 as much as possible. That is, when the MEMS chip 12 is die-bonded on the mounting member 11 or when wire bonding is performed, the MEMS chip 12 is pressed downward, and the portion immediately below the MEMS chip 12 of the mounting member 11 is bent, thereby causing the die to die. It is possible to effectively prevent the occurrence of a bonding failure or a wire bonding failure. In addition, since the portion directly below the MEMS chip 12 of the mounting member 11 bends, the internal space 23 is compressed and narrowed, and the situation where the acoustic resistance increases and the microphone characteristics of the microphone unit 1 deteriorate can be effectively prevented. .

  In the embodiment described above, the mounting member 11 on which the MEMS chip 12 is mounted is configured by bonding the two substrates 111 and 112 together. However, the configuration of the mounting member is not limited to this configuration. For example, the mounting member may be formed of three or more substrates, and in some cases, the mounting member may be formed of one substrate. Further, the mounting member may be configured by combining a plurality of members having different properties, such as a combination of a substrate and a resin molded member.

  FIG. 6 is a diagram illustrating a configuration example of a resin molded member when the mounting member is configured using a substrate and a resin molded member. FIG. 6A is a schematic plan view when the resin molded member is viewed from above. FIG. 6 and FIG. 6B are schematic cross-sectional views at the position AA in FIG. In this case, the substrate constituting the mounting member has the same configuration as the first substrate 111 in the above-described embodiment.

  The resin molding member 113 constituting the mounting member is formed in a box shape having an accommodation recess 113a. The mounting member is formed by fitting the first substrate 111 (see FIG. 2A) into the accommodation recess 113a. On the bottom surface of the housing recess 113a of the resin molding member 113, a groove 113b having a substantially rectangular shape in plan view is formed. Thus, as in the case where the first substrate 111 and the second substrate 112 are bonded together, the first substrate 111 is fitted into the resin forming member 113 so that the first opening and the second opening communicate with each other. An internal space is obtained.

  Further, in the groove 113b of the resin forming member 113, a support portion 14 formed integrally with the resin forming member 113 or bonded to another member is formed, which is the same as the embodiment described above. An effect is obtained. Moreover, although not shown in figure, the electrode connected to the connection terminal of a mounting board is formed in the resin molding member 113 by insert molding, for example.

  In addition, although the material which comprises the resin molding member 113 is not specifically limited, For example, resin, such as LCP (Liquid Crystal Polymer; liquid crystal polymer) and PPS (polyphenylene sulfide), is used.

  In the embodiment described above, the microphone unit is not provided with a lid, but the present invention can be applied to a case where the microphone unit is provided with a lid. FIG. 7 is a diagram illustrating a modification of the microphone unit according to the present embodiment, and is a diagram illustrating a configuration when the microphone unit includes a lid. The microphone unit 2 shown in FIG. 7 is the same as the microphone unit 1 shown in FIG. 1 except that a lid 30 is provided. For this reason, the same code | symbol is attached | subjected to the part which overlaps the structure of FIG.

  The lid body 30 is provided with a substantially rectangular parallelepiped shape, and includes a first space 301 and a second space 302 isolated from the first space 301. The lid 30 is mounted on the mounting member 11 such that the first space 301 is partitioned from the internal space 23 (a space formed in the mounting member 11) by the MEMS chip 12. The lid 30 is mounted on the mounting member 11 so that the second space 302 communicates with the internal space 23 via the second opening 22.

  The upper surface 122 a of the diaphragm 122 communicates with the outside through the first sound holes 31 provided in the first space 301 and the lid body 30. In addition, the lower surface 122 b of the diaphragm 122 communicates with the outside through the first opening 21, the internal space 23, the second opening 22, the second space 302, and the second sound hole 32 provided in the lid body 30. . That is, the microphone unit 2 has a sound path that guides external sound to the upper surface 122a of the diaphragm 122 and a sound path that guides external sound to the lower surface 122b of the diaphragm 122, as shown in FIG. Similarly to the microphone unit 1 shown in FIG. 1, the microphone unit 2 is also a differential microphone unit.

  In the embodiment described above, the MEMS chip 12 and the ASIC 13 are configured as separate chips. However, the integrated circuit mounted on the ASIC 13 is formed monolithically on the silicon substrate on which the MEMS chip 12 is formed. It doesn't matter.

  In the above-described embodiment, the electroacoustic conversion unit that converts sound pressure into an electric signal is the MEMS chip 12 formed by using a semiconductor manufacturing technique. However, the present invention is limited to this configuration. Not the purpose. For example, the electroacoustic conversion unit may be a condenser microphone using an electret film.

  Moreover, in the above embodiment, what was called a capacitor | condenser microphone was employ | adopted as a structure of the electroacoustic conversion part (the MEMS chip 12 of this embodiment corresponds) with which a microphone unit is provided. However, the present invention can also be applied to a microphone unit that employs a configuration other than a condenser microphone. For example, the present invention can also be applied to a microphone unit employing an electrodynamic (dynamic), electromagnetic (magnetic), or piezoelectric microphone.

  The microphone unit of the present invention includes a voice communication device such as a mobile phone and a transceiver, and a voice processing system (a voice authentication system, a voice recognition system, a command generation system, an electronic dictionary, a translation system) that employs a technique for analyzing input voice. Suitable for recording equipment, amplifier systems (loudspeakers), microphone systems, etc.

1, 2 Microphone unit 11 Mounting member 11a Mounting surface 12 MEMS chip (electroacoustic transducer)
14 support part 21 1st opening 22 2nd opening 23 Internal space 23a Upper wall (inner wall of internal space)
23b Lower wall (inner wall of internal space)
30 Lid 31 First sound hole 32 Second sound hole 111 First substrate (part of mounting member)
112 Second substrate (part of mounting member)
113 Resin molding member (part of mounting member)
122 Diaphragm 122a Upper surface of diaphragm (one surface of diaphragm)
122b Lower surface of the diaphragm (the other surface of the diaphragm)
301 1st space 302 2nd space

Claims (6)

An electroacoustic transducer having a diaphragm that is displaced by sound pressure and converting a sound signal into an electrical signal;
A mounting member on which the electroacoustic conversion unit is mounted;
A microphone unit comprising:
A mounting surface on which the electroacoustic conversion unit of the mounting member is mounted is provided with a first opening and a second opening,
The electroacoustic converter is mounted on the mounting member so that the surface to which the sound pressure of the diaphragm is applied is substantially parallel to the mounting surface, and covers the first opening.
The mounting member is provided with an internal space that communicates the first opening and the second opening,
The microphone unit according to claim 1, wherein a support portion that is sandwiched between two opposing inner walls that are substantially parallel to the mounting surface is provided in the internal space.   2. The microphone unit according to claim 1, wherein the support unit is provided so as to overlap the electroacoustic conversion unit in a plan view in a direction substantially orthogonal to the mounting surface.   The microphone unit according to claim 1, wherein the mounting member includes a plurality of members.   The microphone unit according to claim 3, wherein the mounting member is formed by bonding a plurality of substrates.   The microphone unit according to claim 4, wherein the support portion is formed integrally with one of the plurality of substrates. A lid provided with a first space and a second space isolated from the first space;
The lid is mounted on the mounting member such that the first space is partitioned from the internal space by the electroacoustic conversion unit, and the second space communicates with the internal space through the second opening. And
One surface of the diaphragm communicates with the outside through the first space and a first sound hole provided in the lid,
The other surface of the diaphragm communicates with the outside through the first opening, the internal space, the second opening, the second space, and a second sound hole provided in the lid. The microphone unit according to any one of claims 1 to 5, wherein:

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