JP2009100425A - Condenser microphone device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress impulse sound from generating, when impulse is given to a microphone. <P>SOLUTION: Two containers 15, 16 are fixed and disposed on the same side of a device substrate 11. Inside the containers 15, 16, condenser microphone devices 12, 14 are fixed and disposed, while turning the same side to the same direction. An acoustic hole 18 is formed on a ceiling plate 15a of the container 15. An acoustic hole 24 is formed, coaxially with the condenser microphone device 14, from a floor plate 16b of the container 16 to the device substrate 11. Sonic waves are made incident from the acoustic holes 18, 24 and diaphragms 32, 40 of the condenser microphone devices 12, 14 are made vibrate with phases opposite to each other. The impulse makes the diaphragms 32, 40 vibrate mutually in an in-phase manner. Output signals of the condenser microphone devices 12, 14 are subtracted each other and are outputted. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an improvement of a condenser microphone device (including an electret condenser microphone device), and suppresses the generation of impact sound when the condenser microphone device is impacted by hitting the condenser microphone device against an object.

  If the microphone device is accidentally bumped into an object or the like during use, the diaphragm of the microphone device may vibrate and pick up (pick up) an unnecessary impact sound. As a conventional technique for suppressing the generation of such an impact sound, there are methods described in Patent Documents 1 and 2 below. In the technique described in Patent Document 1, the microphone unit is moved with respect to the housing, and when the microphone device is subjected to an impact or vibration, the unit moves to absorb the vibration. As a result, diaphragm vibration is suppressed and noise is reduced. In the technique described in Patent Document 2, a shock sensor is built in the microphone device, and an operation such as attenuating the microphone output according to the output from the shock sensor is added.

JP 2006-217003 A Japanese Patent Laid-Open No. 11-331987

  If a structure that moves the microphone unit relative to the housing is newly provided as in the method described in Patent Document 1, the size of the entire microphone device is increased. Further, the methods described in Patent Documents 1 and 2 cannot cope with thermal noise and electrical noise. The present invention has been made in view of the above-described points, and is a condenser microphone device that can suppress the generation of an impact sound with respect to an impact with a relatively small configuration and can also be configured to suppress thermal noise and electrical noise. Is to provide.

  In the first invention of this application, a diaphragm and a back plate are arranged opposite to each other with an appropriate gap, and the first and second condenser microphone elements having the same characteristics are arranged in separate housing spaces with the same surface facing the same direction. Each housing space is partitioned by the first and second capacitor microphone elements into a space facing the diaphragm and a space facing the back plate, respectively, and the housing of the first capacitor microphone element The partition wall that partitions the space from the external space is formed with an acoustic hole that communicates with the space facing the back plate of the storage space, and the partition wall that partitions the storage space of the second condenser microphone element from the external space Forming an acoustic hole communicating with the space of the housing space facing the diaphragm, and taking a difference between outputs of the first and second condenser microphone elements. Outputs Te, or first to a difference in subsequent circuit, in which the outputs of the second microphone chip respectively output.

  According to the first invention, since the diaphragms of the first and second condenser microphone elements vibrate in opposite phases with respect to the sound, each element is used alone by taking the difference in output between the two elements. A larger output than the case can be obtained. On the other hand, since the diaphragms of both elements vibrate in the same phase in response to an impact, by taking the difference between the outputs of both elements, signals due to the impact cancel each other and the generation of an impact sound can be suppressed. Further, by taking the difference between the outputs of the two elements, signals due to thermal noise and electrical noise that are generated in common to both elements cancel each other, and the generation of the noise can be suppressed.

  Specifically, in the first invention, for example, the accommodation spaces of the first and second condenser microphone elements are respectively configured by individual containers, and the containers are respectively fixed on the same surface side of the apparatus substrate, The first and second condenser microphone elements are fixed to the floor plate in each container in a posture with the diaphragm side facing the floor board, and the acoustic hole on the first condenser microphone element side is the ceiling plate of the container The acoustic hole on the second condenser microphone element side is formed from the floor plate of the container to the device substrate. In this case, the containers and the apparatus substrate are further accommodated in one housing, and acoustic holes communicating with the acoustic holes on the first and second condenser microphone elements are formed in the housing. Can be configured.

  According to a second aspect of the present application, the diaphragm and the back plate are arranged to face each other with an appropriate gap, and the first and second condenser microphone elements having the same characteristics are separated from each other with the same surfaces facing in opposite directions. The first and second capacitor microphone elements are divided into a space on the side facing the diaphragm and a space on the side facing the back plate by the first and second capacitor microphone elements, respectively. The partition walls that partition the housing space from the external space are both formed with acoustic holes communicating with the space on the side facing the back plate of the housing space, or both on the space on the side facing the diaphragm of the housing space. An acoustic hole that communicates with each other is formed, and the sum of the outputs of the first and second condenser microphone elements is output. First, in which the outputs of the second microphone chip respectively output in order.

  According to the second invention, since the diaphragms of the first and second condenser microphone elements vibrate in phase with each other with respect to sound, the sum of the outputs of both elements can be used to obtain a higher than that when each element is used alone. Can produce a large output. On the other hand, since the diaphragms of both elements vibrate in antiphase with respect to the impact, by taking the sum of the outputs of both elements, signals due to the impact cancel each other, and the generation of impact sound can be suppressed.

  Specifically, in the second invention, for example, the accommodation spaces of the first and second condenser microphone elements are respectively configured by individual containers, and the containers are respectively fixed on the same surface side of the apparatus substrate, The first condenser microphone element is fixed to the floor plate in the container with the diaphragm side facing the floor plate, and the second condenser microphone element is on the ceiling plate in the container and the diaphragm side is on the ceiling plate. The acoustic hole on the first condenser microphone element side is fixed in a facing posture, and the acoustic hole on the second condenser microphone element side is formed from the floor plate of the container to the device. It can be configured to be formed over the substrate. In this case, the containers and the apparatus substrate are further accommodated in one housing, and acoustic holes communicating with the acoustic holes on the first and second condenser microphone elements are formed in the housing. Can be configured.

  The first and second capacitor microphone elements of the present invention can be constituted by, for example, MEMS (Micro Electro Mechanical Systems) elements, or can be constituted by assembling individual parts.

Embodiment 1
Embodiment 1 of the present invention is shown in FIG. 1A is an elevation view showing the internal structure, and is a diagram showing the entire condenser microphone device in half along the longitudinal direction (a cross-sectional view taken along the line B-B in FIG. 1B), and FIG. It is a top view which shows an internal structure, and is AA arrow sectional drawing of (a), (c) is a top view, (d) is a bottom view. In the capacitor microphone device 10, two containers 15 and 16 are fixedly arranged on the same surface side of one device substrate 11. In each of the containers 15 and 16, condenser microphone devices 12 and 14 are accommodated and fixedly arranged. That is, the two capacitor microphone elements 12 and 14 are fixed on the floor plates 15b and 16b of the containers 15 and 16 with an adhesive or the like with the same surface facing the same direction. An acoustic hole 18 is formed in the ceiling plate 15 a of the container 15. The internal space 20 and the external space 22 of the container 15 communicate only through the acoustic hole 18. An acoustic hole 24 (having the acoustic hole 24a on the container 16 side and the acoustic hole 24b on the apparatus substrate 11 side coaxially) is formed coaxially with the capacitor microphone element 14 from the floor plate 16b of the container 16 to the device substrate 11. . The internal space 26 and the external space 22 of the container 16 communicate with each other only through the acoustic hole 24. When the condenser microphone device 10 is mounted on a device such as a mobile phone terminal, it is mounted so that the acoustic holes 18 and 24 are not blocked. Further, an impedance converter (not shown) is attached to the device substrate 11 (or the impedance converter can be arranged at a place other than the device substrate 11).

  The capacitor microphone elements 12 and 14 have structures and characteristics that are equal to each other, and can be configured by, for example, well-known silicon microphones using MEMS elements. FIG. 1 also shows a case where the capacitor microphone elements 12 and 14 are formed of silicon microphones. The capacitor microphone element 12 includes a substrate 28 made of silicon or the like. The lower end of the substrate 28 is fixed on the floor plate 15b of the container 15 with an adhesive or the like. An opening 30 in the vertical direction (axial direction) is formed in the substrate 28. The lower end of the opening 30 is closed with a floor plate 15 b of the container 15. A diaphragm 32 on the lower side and a back plate 34 on the upper side of the upper end portion of the substrate 28 are opposed to each other with an appropriate gap so as to close the opening 30. A minute through hole 32 a for adjusting the atmospheric pressure is formed at the peripheral edge of the diaphragm 32. A plurality of through holes 34 a are formed in the surface of the back plate 34. The acoustic hole 18 of the container 15 is formed coaxially with the capacitor microphone element 12 or at a position shifted from the axis of the capacitor microphone element 12. Sound waves in the external space 22 are incident from the acoustic holes 18 and pass through the through holes 34 a of the back plate 34 to vibrate the diaphragm 32. The internal space 20 is partitioned by the capacitor microphone element 12 into a space 20a facing the diaphragm 32 and a space 20b facing the back plate 34. The acoustic hole 18 communicates with the space 20b on the side where the back plate 34 faces.

  The capacitor microphone element 14 includes a substrate 36 made of silicon or the like. The lower end of the substrate 36 is fixed on the floor plate 16b of the container 16 with an adhesive or the like. An opening 38 in the vertical direction (axial direction) is formed in the substrate 36. The lower end of the opening 38 communicates with the acoustic hole 24 coaxially. A diaphragm 40 on the lower side and a back plate 42 on the upper side of the upper end portion of the substrate 36 are opposed to each other with an appropriate gap so as to close the opening 38. A minute through hole 40 a for adjusting the atmospheric pressure is formed at the peripheral edge of the diaphragm 40. A plurality of through holes 42 a are formed in the surface of the back plate 42. Sound waves in the external space 22 are incident from the acoustic hole 24 and vibrate the diaphragm 40. The internal space 26 is partitioned by the condenser microphone element 14 into a space 26a facing the diaphragm 40 and a space 26b facing the back plate 42. The acoustic hole 24 communicates with the space 26a on the side where the diaphragm 40 faces.

  The operation of the capacitor microphone device 10 having the above configuration will be described. FIG. 2 shows the operation when the sound wave S1 is incident from the outside. At this time, the sound wave S1 from the outside enters the condenser microphone element 12 from the acoustic hole 18 and enters the condenser microphone element 14 from the acoustic hole 24 to vibrate the diaphragms 32 and 40 in opposite phases. . FIG. 3 shows output signal waveforms of the capacitor microphone elements 12 and 14 at this time. Since the diaphragms 32 and 40 vibrate in opposite phases, the output signal waveforms are in opposite phases.

  FIG. 4 shows the operation when an impact is applied from the outside. At this time, an impact is applied to the diaphragms 32 and 40 of the capacitor microphone elements 12 and 14 in the same direction, so that the diaphragms 32 and 40 are displaced in the same direction by the inertia due to the impact and vibrate in phase with each other. FIG. 5 shows output signal waveforms of the capacitor microphone elements 12 and 14 at this time. Since the diaphragms 32 and 40 vibrate in phase with each other due to the impact, the output signal waveforms are in phase with each other.

FIG. 6 shows an equivalent circuit of the signal processing circuit of the capacitor microphone device 10 (impedance converter is not shown). The output signals of the capacitor microphone elements 12 and 14 are subtracted from each other by the subtractor 44 via the impedance converter and output. Of the outputs of the capacitor microphone elements 12 and 14, a component due to sound waves is S, a component due to impact is N, and a component due to thermal noise or electrical noise is n. In the capacitor microphone elements 12 and 14, the components S are out of phase with each other, and the components N and n are in phase with each other, so the outputs of the capacitor microphone elements 12 and 14 are as follows.
・ Output of condenser microphone element 12 = + S + N + n
Output of condenser microphone element 14 = −S + N + n
Therefore, the output of the subtracter 44 = + 2S
It becomes. In other words, the output of the sound is twice that when the elements 12 and 14 are used alone, and the impact sound, thermal noise and electrical noise are canceled out.

  The subtracter 44 can be mounted on the device substrate 11 or disposed outside the condenser microphone device 10. When the subtractor 44 is mounted on the device substrate 11, the subtraction result is output from the capacitor microphone device 10. When the subtractor 44 is arranged outside the capacitor microphone device 10, the output signals of the capacitor microphone elements 12 and 14 subjected to impedance conversion are output from the capacitor microphone device 10, respectively.

<< Embodiment 2 >>
A second embodiment of the present invention is shown in FIG. 7A is an elevation view showing the internal structure, and is a diagram showing the entire condenser microphone device in half along the longitudinal direction (cross-sectional view taken along the line CC in FIG. 7B), and FIG. A top view and (c) are bottom views. The same reference numerals are used for portions common to the first embodiment in FIG. In the capacitor microphone device 50, two containers 15 and 16 are fixedly arranged on the same surface side of one device substrate 11. In each of the containers 15 and 16, condenser microphone devices 12 and 14 are accommodated and fixedly arranged. That is, the capacitor microphone element 12 is fixed on the floor plate 15b of the container 15 with an adhesive or the like. An acoustic hole 18 is formed in the ceiling plate 15 a of the container 15. The internal space 20 and the external space 22 of the container 15 communicate only through the acoustic hole 18. In the container 16, the capacitor microphone element 14 is fixed to the ceiling plate 16 a of the container 16 with an adhesive or the like with the capacitor microphone element 12 turned upside down (that is, with the same surface directed in the opposite direction). From the floor plate 16b of the container 16 to the device substrate 11, an acoustic hole 24 (an acoustic hole 24a on the container 16 side and an acoustic hole 24b on the device substrate 11 side) is positioned coaxially with the capacitor microphone element 14 or offset from the axis of the capacitor microphone element 14. Are arranged coaxially). The internal space 26 and the external space 22 of the container 16 communicate with each other only through the acoustic hole 24. When the condenser microphone device 50 is mounted on a device such as a mobile phone terminal, it is mounted so that the acoustic holes 18 and 24 are not blocked. Further, an impedance converter (not shown) is attached to the device substrate 11 (or the impedance converter can be arranged at a place other than the device substrate 11). The capacitor microphone elements 12 and 14 are the same as the capacitor microphone elements 12 and 14 in FIG. The internal space 20 is partitioned by the capacitor microphone element 12 into a space 20a facing the diaphragm 32 and a space 20b facing the back plate 34. The acoustic hole 18 communicates with the space 20b on the side where the back plate 34 faces. The internal space 26 is partitioned by the condenser microphone element 14 into a space 26a on the side facing the diaphragm 40 and a space 26b on the side facing the back plate 42. The acoustic hole 24 communicates with the space 26b on the side where the back plate 42 faces.

  The operation of the condenser microphone device 50 having the above configuration will be described. FIG. 8 shows the operation when the sound wave S1 is incident from the outside. At this time, the sound wave S1 from the outside enters the condenser microphone element 12 from the acoustic hole 18 and enters the condenser microphone element 14 from the acoustic hole 24, and causes the diaphragms 32 and 40 to vibrate in the same phase. The output signal waveforms of the capacitor microphone elements 12 and 14 at this time are the same as the waveforms (a) and (b) of FIG.

  FIG. 9 shows the operation when an impact is applied from the outside. At this time, shocks are applied to the diaphragms 32 and 40 of the capacitor microphone elements 12 and 14 in the same direction, so that the diaphragms 32 and 40 are displaced in the same direction by the inertia due to the shocks and vibrate in opposite phases. The output signal waveforms of the capacitor microphone elements 12 and 14 at this time are the same as the waveforms (a) and (b) of FIG.

FIG. 10 shows an equivalent circuit of the signal processing circuit of the capacitor microphone device 50. The output signals of the capacitor microphone elements 12 and 14 are added together by the adder 52 and output. When the component due to the sound wave is S, the component due to the impact is N, and the component due to thermal noise or electrical noise is n among the outputs of the capacitor microphone elements 12 and 14, the components S are in phase with each other in the capacitor microphone elements 12 and 14. Since the components N are out of phase with each other and the components n are in phase with each other, the outputs of the capacitor microphone elements 12 and 14 are as follows.
・ Output of condenser microphone element 12 = + S + N + n
・ Output of condenser microphone element 14 = + S−N + n
Therefore, the output of the adder 52 = + 2S + 2n
It becomes. That is, the output of the voice is twice that when the elements 12 and 14 are used alone. Thermal noise and electrical noise remain, but the impact sound is canceled out.

  The adder 52 can be mounted on the device substrate 11 or disposed outside the condenser microphone device 10. When the adder 52 is mounted on the device substrate 11, the addition result is output from the capacitor microphone device 10. When the adder 52 is disposed outside the condenser microphone device 10, the output signals of the condenser microphone elements 12 and 14 subjected to impedance conversion are output from the condenser microphone device 10, respectively.

<< Embodiment 3 >>
A third embodiment of the present invention is shown in FIG. The same reference numerals are used for parts common to the first and second embodiments in FIGS. In this condenser microphone device 60, both condenser microphone elements 12 and 14 are fixedly arranged on the ceiling plates 15 a and 16 a of the containers 15 and 16 with the same surface facing the same direction. The acoustic hole 18 on the condenser microphone element 12 side (the acoustic hole 18 a on the container 15 side and the acoustic hole 18 b on the apparatus substrate 11 side arranged coaxially) is formed from the floor plate 15 b of the container 15 to the apparatus substrate 11. The acoustic hole 18 communicates with the space 20b on the side where the back plate 34 faces. The acoustic hole 24 on the condenser microphone element 14 side is formed coaxially with the condenser microphone element 14 at the center of the ceiling plate 16 a of the container 16. According to the capacitor microphone device 60, the diaphragms 32 and 40 of the capacitor microphone elements 12 and 14 vibrate in opposite phases with respect to sound waves and vibrate in phase with respect to impacts. Therefore, the outputs of the capacitor microphone elements 12 and 14 are the same as those in the first embodiment (the waveforms in FIGS. 3 and 5) and can be processed by the circuit in FIG. The acoustic hole 24 communicates with the space 26a on the side where the diaphragm 40 faces.

<< Embodiment 4 >>
A fourth embodiment of the present invention is shown in FIG. The same reference numerals are used for parts common to the first, second, and third embodiments of FIGS. In this condenser microphone device 70, the condenser microphone element 12 is fixedly arranged on the floor plate 15 b in the container 15, and the condenser microphone element 14 is fixedly arranged on the ceiling board 16 a in the container 16. That is, the capacitor microphone elements 12 and 14 are arranged with the same surfaces facing in opposite directions. The acoustic hole 18 on the condenser microphone element 12 side (the acoustic hole 18a on the container 15 side and the acoustic hole 18b on the apparatus substrate 11 side arranged coaxially) is coaxial with the condenser microphone element 12 from the floor plate 15b of the container 15 to the apparatus substrate 11. Is formed. The acoustic hole 18 communicates with the space 20a on the side where the diaphragm 32 faces. The acoustic hole 24 on the condenser microphone element 14 side is formed coaxially with the condenser microphone element 14 at the center of the ceiling plate 16 a of the container 16. The acoustic hole 24 communicates with the space 26a on the side where the diaphragm 40 faces. According to the capacitor microphone device 70, the diaphragms 32 and 40 of the capacitor microphone elements 12 and 14 vibrate in the same phase with respect to the sound wave, and vibrate in opposite phases with respect to the impact. Therefore, the outputs of the capacitor microphone elements 12 and 14 are the same as those in the second embodiment, and can be processed by the circuit shown in FIG.

<Example of implementation>
An example of mounting the condenser microphone device of the present invention is shown in FIG. This is a condenser microphone device of the type of the second embodiment (FIG. 7). (A) is a sectional elevation view showing the internal structure, (b) is a plan view. The same reference numerals are used for parts common to FIG. In this condenser microphone device 80, the device substrate 11 is fixedly supported on a support leg 84 installed on a floor plate 82 b in the housing 82. On the substrate 11, the container 15 is attached and fixed by solder 86, and the container 16 is attached and fixed by solder 88. The solder 86 constitutes a wiring that connects the capacitor microphone element 12 housed and fixed in the container 15 and a wiring (not shown) formed on the device substrate 11. The solder 88 constitutes a wiring that connects the capacitor microphone element 14 accommodated and fixed in the container 16 and a wiring (not shown) formed on the device substrate 11. The wiring of the device substrate 11 is connected to wiring (not shown) outside the housing 82. The impedance converter can be disposed on the device substrate 11 as long as it is within the housing 82. Alternatively, the impedance converter can be disposed outside the housing 82.

  An acoustic hole 90 is formed in the ceiling plate 82 a of the housing 82 coaxially with the acoustic hole 18 formed in the ceiling plate 15 a of the container 15. A rubber O-ring 92 is sandwiched between the ceiling plate 82 a of the casing 82 and the ceiling plate 15 a of the container 15 so as to surround the acoustic holes 18 and 90. As a result, the acoustic holes 18 and 90 communicate with each other, and sound waves in the external space 22 entering from the acoustic hole 90 enter the internal space 20 of the container 15 through the acoustic holes 18 to vibrate the diaphragm 32 of the condenser microphone element 12. .

  The floor plate 82b of the casing 82 is coaxial with the acoustic hole 24 formed from the floor plate 16b of the container 16 to the device substrate 11 (the acoustic hole 24a on the container 16 side and the acoustic hole 24b on the device substrate 11 side are arranged coaxially). An acoustic hole 94 is formed in the bottom. Between the floor plate 16a of the container 16 and the apparatus substrate 11, a seal 96 made of solder is attached so as to surround the acoustic holes 24a and 24b. A rubber O-ring 98 is sandwiched between the device substrate 11 and the floor plate 82 b of the housing 82 so as to surround the acoustic holes 24 b and 94. As a result, the acoustic holes 24a, 24b, and 94 communicate with each other, and the sound wave in the external space 22 that enters from the acoustic hole 94 enters the internal space 26 of the container 16 through the acoustic holes 24b and 24a, and the diaphragm of the condenser microphone element 14 40 is vibrated.

  In each of the embodiments, the capacitor microphone elements 12 and 14 are disposed on the same surface side of the device substrate 11, but may be disposed on the opposite surfaces of the device substrate 11. Also in this case, the capacitor microphone elements 12 and 14 are fixed to the ceiling plates 15a and 16a side of the containers 15 and 16 or fixed to the floor plates 15b and 16b side of the containers 15 and 16, and the acoustic holes 18 and 24 are connected to the containers 15 and 16 respectively. Various combinations such as forming from the floor plates 15b, 16b to the apparatus substrate 11 or forming the containers 15 and 16 on the ceiling plates 15a, 16a side are possible. In each of the above embodiments, the containers 15 and 16 are provided separately for each of the capacitor microphone elements 12 and 14, but the container is provided as one and a partition is provided therein to form two internal spaces. The capacitor microphone elements 12 and 14 can be accommodated respectively.

  In each of the above embodiments, the accommodating spaces 20 and 26 of the capacitor microphone elements 12 and 14 are configured by only the containers 15 and 16, but the present invention is not limited to this. For example, the floor plates 15b and 16b of the containers 15 and 16 are eliminated, and the openings are opened, and the opened lower end surfaces of the containers 15 and 16 are hermetically joined to the apparatus substrate 11 so that the containers 15 and 16 and the apparatus substrate 11 are opened. The accommodating spaces 20 and 26 can also be configured. In this case, the capacitor microphone element that is adhered and fixed to the floor plates 15b and 16b of the containers 15 and 16 in each of the above embodiments (FIG. 1 shows both elements 12 and 14, FIG. 7 shows the element 12, FIG. 11 shows no corresponding element, In FIG. 12, the element 12) is directly bonded and fixed on the device substrate 11.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows Embodiment 1 of this invention, (a) is a sectional elevational view which shows an internal structure, (b) is a sectional plan view which shows an internal structure, (c) is a top view, (d) is a bottom view. It is. It is a schematic diagram which shows operation | movement of a diaphragm when the sound wave S1 injects into the capacitor | condenser microphone apparatus 10 of FIG. 1 from the outside. FIG. 3 is an output signal waveform diagram of capacitor microphone elements 12 and 14 by the operation of FIG. 2. It is a schematic diagram which shows the operation | movement of a diaphragm when an external impact is added to the capacitor | condenser microphone apparatus 10 of FIG. FIG. 5 is an output signal waveform diagram of the capacitor microphone elements 12 and 14 by the operation of FIG. 4. FIG. 2 is an equivalent circuit diagram of a signal processing circuit of the capacitor microphone device 10 of FIG. 1. It is a figure which shows Embodiment 2 of this invention, (a) is a sectional elevation view which shows an internal structure, (b) is a top view, (c) is a bottom view. It is a schematic diagram which shows operation | movement of a diaphragm when the sound wave S1 injects into the condenser microphone apparatus 50 of FIG. 7 from the outside. It is a schematic diagram which shows the operation | movement of a diaphragm when an external impact is applied to the capacitor | condenser microphone apparatus 50 of FIG. FIG. 8 is an equivalent circuit diagram of a signal processing circuit of the capacitor microphone device 50 of FIG. 7. It is a section elevation showing the internal structure of Embodiment 3 of this invention. It is a section elevation showing the internal structure of Embodiment 4 of this invention. It is a figure which shows the example of mounting of the capacitor | condenser microphone apparatus of the type of Embodiment 2 (FIG. 7), (a) is a sectional elevation view which shows an internal structure, (b) is a top view.

Explanation of symbols

  10, 50, 60, 70, 80 ... condenser microphone device, 11 ... device substrate, 12, 14 ... capacitor microphone element, 15, 16 ... container, 15a, 16a ... container ceiling plate, 15b, 16b ... container floor plate, 18, 24 (24a, 24b) ... acoustic holes, 20, 26 ... accommodating space (internal space), 20a, 26a ... space on the side facing the diaphragm, 20b, 26b ... space on the side facing the back plate, 22 ... external space 32, 40 ... Diaphragm, 34, 42 ... Back plate, 44 ... Subtractor, 52 ... Adder, 82 ... Housing, 90, 92 ... Acoustic hole in housing

Claims (5)

The diaphragm and the back plate are arranged opposite to each other with an appropriate gap, and the first and second capacitor microphone elements having the same characteristics are accommodated in separate accommodation spaces with the same surface facing the same direction,
Each housing space is partitioned by the first and second condenser microphone elements into a space facing the diaphragm and a space facing the back plate, respectively.
The partition wall that partitions the housing space of the first capacitor microphone element from the external space is formed with an acoustic hole communicating with the space on the side of the housing space facing the back plate,
The partition wall that partitions the housing space of the second capacitor microphone element from the external space is formed with an acoustic hole communicating with the space on the side of the housing space where the diaphragm faces,
A condenser microphone device that outputs a difference between outputs of the first and second condenser microphone elements, or outputs each output of the first and second condenser microphone elements to obtain a difference in a subsequent circuit. The accommodation spaces of the first and second condenser microphone elements are respectively constituted by individual containers,
Each container is fixed to the same surface side of the device substrate,
The first and second condenser microphone elements are respectively fixed to the floor plate in each container in a posture in which the diaphragm side faces the floor plate,
The acoustic hole on the first condenser microphone element side is formed in the ceiling plate of the container,
The condenser microphone device according to claim 1, wherein the acoustic hole on the second capacitor microphone element side is formed from a floor plate of the container to the device substrate. The diaphragm and the back plate are arranged opposite to each other with an appropriate gap, and the first and second capacitor microphone elements having the same characteristics are accommodated in separate accommodation spaces with the same surfaces facing in opposite directions.
Each housing space is partitioned by the first and second condenser microphone elements into a space facing the diaphragm and a space facing the back plate, respectively.
The partition walls that partition the housing spaces of the first and second condenser microphone elements from the external space are each formed with an acoustic hole communicating with the space on the side of the housing space facing the back plate, or both of the housing spaces. Acoustic holes communicating with the space on the side facing the diaphragm are respectively formed,
A condenser microphone device that outputs a sum of outputs of the first and second condenser microphone elements, or outputs each output of the first and second condenser microphone elements for summation in a subsequent circuit. The accommodation spaces of the first and second condenser microphone elements are respectively constituted by individual containers,
Each container is fixed to the same surface side of the device substrate,
The first condenser microphone element is fixed to the floor plate in the container in a posture in which the diaphragm side faces the floor plate,
The second condenser microphone element is fixed to the ceiling plate in the container in a posture in which the diaphragm side faces the ceiling plate,
The acoustic hole on the first condenser microphone element side is formed in the ceiling plate of the container,
4. The condenser microphone device according to claim 3, wherein the acoustic hole on the second capacitor microphone element side is formed from a floor plate of the container to the device substrate.   The container and the apparatus substrate are accommodated in a single housing, and acoustic holes communicating with the acoustic holes on the first and second condenser microphone elements are formed in the housing. 2. The condenser microphone device according to 2 or 4.

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