JP2007104582A - Microphone device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable directive sound collection and stereo sound collection which are highly accurate and stable with a sole small microphone device. <P>SOLUTION: MEMS sound collection elements 11a, 11b excellent in high accuracy and stability which are manufactured using a MEMS technique are arranged in parallel, mounted on a mounting substrate 65 and housed in a capsule 64. The capsule 64 has a structure capable of preventing leak-out of diffraction acoustic sounds. For example, a capsule 90 has a mesh structure of acoustic transmittivity. With this configuration, acoustic paths (P1, P2) are integrated, and directive sound collection can be executed by appropriate operation processing. <P>COPYRIGHT: (C)2007,JPO&amp;INPIT

Description

  The present invention relates to a microphone device, and more particularly to a microphone device capable of directional sound collection (including stereo sound collection).

A conventional example in which a pair of electret condenser microphones (ECM) capable of directional sound collection is mounted is described in Patent Document 1 (see FIG. 1B of Patent Document 1).
Hereinafter, the structure of the conventional example described in FIG. 1B of Patent Document 1 will be briefly described with reference to FIG.
FIG. 7 is a cross-sectional view showing a structure of a conventional example (an example in which a pair of electret condenser microphones are housed in a common capsule) described in FIG.

  As shown in the figure, the microphone device of Patent Document 1 is configured by arranging a pair of acoustic transducer units symmetrically in a common capsule 84. The acoustic transducer unit is formed by a diaphragm 76, a spacer 77, and a back pole 78. The acoustic transducer unit performs acoustic-electric signal conversion, and an acoustic signal input is converted into an electrical signal output via an impedance conversion circuit 82. Convert.

  In FIG. 7, reference numeral 75 is a diaphragm ring, reference numeral 79 is a sound hole, reference numeral 80 is a back electrode holder, reference numeral 81 is a conversion circuit housing portion, and reference numeral 83 is a shielding plate. It is.

In the microphone device of FIG. 7, an impedance conversion circuit 82 is mounted at the center of the shielding plate 83, a back electrode holder 80, a conversion circuit housing portion 81 are formed, a transducer portion is formed, and a capsule 84 is covered. The capsule 84 is manufactured through a mechanical assembly process in which the lower end of the capsule 84 is bent inward by a caulking method.
In addition, the sensitivity of an array microphone composed of multiple microphones arranged at a predetermined position can be obtained by appropriately delaying and adding / subtracting the output of each microphone by utilizing the fact that the acoustic path from the sound source to each microphone is different. It is known to have directivity when applied (see, for example, JP-A-7-131886).

  For example, a sound coming from a predetermined direction is received by the first and second sound collecting elements, and the second sound collecting element receives sound after a delay of Δt after the first sound collecting element receives the sound. Assume a case. In this case, if the output signal from the second sound collection element is delayed by Δt and then added to the signal obtained from the first sound collection element, the same signals are superimposed on each other, but the sound from the other direction is superimposed. Since no superposition effect is obtained, the sound receiving sensitivity is improved with respect to the sound from the predetermined direction, and directional sound reception is possible.

  In other words, the difference in the acoustic path from the sound source to each sound collecting element that makes up the array microphone is a prerequisite for directivity formation, but there are multiple acoustic paths from one sound source to one sound collecting element. Then (for example, there may be a plurality of acoustic paths due to the sound diffraction phenomenon), it is impossible to appropriately set the delay amount and coefficient for directivity formation, and it is impossible to form good directivity. Become.

JP 2000-165998 A JP-A-7-131886

  However, in the conventional microphone device described in Patent Literature 1, when the microphone is mechanically assembled using the caulking method, if the capsule (reference numeral 84) is caulked, the diaphragm ring (reference numeral 75) and the spine It is difficult to apply a load equally to the poles (reference numeral 78), and the tension of each diaphragm 76 changes, so that the sensitivity of each transducer section is difficult to be uniform. That is, the sensitivity of the plurality of sound collection elements (transducers) varies. This point hinders the realization of highly accurate and stable directivity.

  The present invention has been made in view of the above circumstances, and an object thereof is to realize highly accurate and stable directivity using one microphone module in which at least two sound pickup elements are housed in a capsule. .

  The microphone device of the present invention performs predetermined arithmetic processing based on the first and second sound collecting elements manufactured by using a semiconductor manufacturing process and the output signals of the first and second sound collecting elements. A signal processing unit, a microphone capsule that is disposed so as to cover the first and second sound collecting elements and the signal processing unit, and at least a part of which constitutes an acoustically permeable mesh structure unit; A part of the sound from one sound source to the first sound collecting element is prevented from diffracting to reach the second sound collecting element, and the sound from one sound source to the second sound collecting element is prevented. A part is prevented from reaching the first sound collecting element by diffraction.

  Capacitive sound pickup elements (MEMS sound pickup elements) manufactured using silicon LSI microfabrication technology (MEMS technology) have higher processing accuracy than sound pickup elements manufactured by assembling mechanical parts. The accuracy of electroacoustic conversion is high and stable. Using this advantage, at least two sound pickup elements manufactured by using a semiconductor manufacturing process are housed in a common microphone capsule to constitute one microphone device (microphone module). However, if there are multiple acoustic paths from the sound source to each sound collection element due to sound diffraction, it becomes difficult to form directivity, so a capsule (casing) with a structure that can prevent the generation of acoustic paths due to diffraction is provided. Adopted. Thereby, it is possible to realize highly accurate and stable directivity using one microphone module in which at least two sound pickup elements are housed in a capsule.

In the microphone device according to the present invention, at least a part of the microphone capsule has an acoustically permeable mesh structure.
Sound is inherently straight, and no diffraction phenomenon occurs unless there is a path obstruction under predetermined conditions. Therefore, at least a part of the capsule (especially, a portion necessary for sound to reach the vibrating membrane of each sound collecting element) has an acoustically transparent (acoustic transmission) mesh structure (this mesh is In this structure, the sound arriving from the sound source goes straight and reaches each sound collecting element. The sound from the sound source goes straight without reaching the sound collection elements without being blocked by the casing (capsule) of the microphone device. That is, an acoustic path to one sound collection element is uniquely determined without causing an adverse effect due to acoustic diffraction. Accordingly, it is possible to appropriately set the delay amount and coefficient for directivity formation, and it is possible to form good directivity.

According to the present invention, in the microphone device, the acoustically transparent mesh structure includes a conductive material.
Since the mesh portion forms a part of the casing (capsule), it is desirable not only to guide the sound from the sound source to the sound collecting element but also to have an electromagnetic noise shielding effect. Therefore, a mesh is formed from a conductive material (metal) to obtain an electromagnetic shielding effect.

Further, according to the present invention, in the microphone device, the signal processing unit performs delay processing and addition / subtraction processing on the output signals of the first and second sound collection elements, thereby realizing directional sound collection. Including things.
According to the above configuration, the signal processing unit that performs signal processing necessary for directional sound collection (including stereo sound collection) is also housed in the casing (capsule). As a result, a one-module microphone device capable of highly accurate and stable directional sound collection (including stereo sound collection) is obtained.

In the microphone device according to the present invention, the first and second sound collecting elements and the signal processing unit are mounted on a common substrate.
According to the above configuration, the sound collection element and the signal processing unit are mounted on the common substrate, and the capsule is placed on the substrate to form one module. For example, the signal processing unit is made into an LSI, the LSI is mounted between a pair of adjacent sound collecting elements, and the LSI and each sound collecting element on both sides are connected by a bonding wire or the like for electrical conduction. Therefore, a useless space can be reduced, and a very compact module (microphone device) having a directional sound collecting function can be obtained.

Further, the present invention includes the microphone device in which the first and second sound collection elements and the signal processing unit are integrated on the same substrate.
According to the above configuration, the sound collecting element and the signal processing unit are integrated and formed on the same substrate, and the capsule is placed on the substrate to form one module. Desirably, the first and second sound collection elements and the signal processing unit are made into LSI, and the LSI is covered with a microcapsule having a partition wall having an opening formed by a MEMS process. A module (microphone device) having a directional sound collection function can be obtained.

Further, the present invention includes the above microphone device in which the microphone capsule is formed by processing a substrate by a MEMS process.
According to the above configuration, it is possible to further reduce the size and thickness.

  According to the present invention, MEMS sound pickup elements manufactured using MEMS technology and having high accuracy and excellent stability are accommodated in a capsule in a state of being arranged in parallel, and the capsule leaks diffractive sound. By using a compact microphone module in which at least two sound pickup elements are housed in a capsule by unifying the acoustic path as a structure (a structure having a partition wall that airtightly separates the sound pickup elements), High precision and stable directivity can be easily realized.

  In other words, the mesh structure provided in the capsule prevents the sound that has passed through the sound hole for one sound collecting element from wrapping around and reaching the other sound collecting element due to diffraction. Can be Accordingly, it is possible to appropriately set the delay amount and coefficient for directivity formation, and it is possible to form good directivity.

In addition, by accommodating the signal processing unit in the capsule, a microphone device in a single module capable of highly accurate and stable directional sound collection (including stereo sound collection) can be obtained.
Moreover, the shielding effect of electromagnetic noise can be obtained by using a conductive mesh.

  Further, by mounting the sound collecting element and the signal processing unit on a common substrate and covering the substrate with a capsule to form one module, a compact one-module microphone device can be obtained. For example, the signal processing unit is made into an LSI, the LSI is mounted between a pair of adjacent sound collecting elements, and the LSI and each sound collecting element on both sides are connected by a bonding wire or the like for electrical conduction. Therefore, a wasteful space can be reduced, and a very compact microphone device having a directional sound collecting function can be realized.

  According to the present invention, it is possible to provide a microphone device having an effect that directional sound collection and stereo sound collection can be performed with a small microphone device alone.

Next, embodiments of the present invention will be described with reference to the drawings.
(Embodiment 1)
FIG. 1 is a cross-sectional view showing an internal configuration of an embodiment of the microphone device of the present invention (an example in which at least a part of a microcapsule has an acoustically transparent mesh structure), and FIG. 2 is a MEMS used here. It is sectional drawing which shows the sound collection element of a structure.

  As shown in FIG. 1, the microphone device has first and second sound pickup elements manufactured by using a semiconductor manufacturing process, and predetermined signals based on output signals of the first and second sound pickup elements. A signal processing unit that performs arithmetic processing, the first and second sound collecting elements, and the signal processing unit are housed, and a part of the sound from one sound source toward the first sound collecting element is caused by diffraction. A structure that prevents the second sound collecting element from reaching the second sound collecting element and prevents a part of the sound traveling from one sound source toward the second sound collecting element from reaching the first sound collecting element by diffraction. And a microphone capsule having a mesh structure that is at least partially acoustically transparent (acoustic transmission).

  As described above, the microphone device of the present embodiment employs an acoustically transparent (acoustic transmissive) mesh structure as the microphone capsule 90, and is a highly accurate and stable MEMS sound pickup element. Are placed in a capsule in parallel, and the capsule has an acoustically transparent (acoustic transmission) mesh structure for at least part of the capsule to prevent leakage of diffractive sound. This is a feature.

  Sound is inherently straight, and no diffraction phenomenon occurs unless there is a path obstruction under predetermined conditions. Therefore, the entire capsule 90 has an acoustically transparent (acoustic transmission) mesh structure (this mesh has a structure having a large number of holes having a diameter that does not cause adverse effects due to acoustic diffraction). The sound arriving from is straight ahead and reaches each sound collecting element.

  Thereby, the sound from the sound source goes straight as it is and is not blocked by the capsule (casing) 90 of the microphone device and reaches each sound collecting element. In other words, the acoustic paths reaching one sound collecting element are P1 and P2 and are unified without adverse effects due to acoustic diffraction. Accordingly, it is possible to appropriately set the delay amount and coefficient for directivity formation, and it is possible to form good directivity.

  In addition, since a mesh structure is formed by processing a material having conductivity such as metal, an electromagnetic noise shielding effect (shielding) can be obtained. Therefore, no problem arises with electromagnetic noise shielding.

  In addition, two sound pickups manufactured using a silicon manufacturing process (MEMS technology) provided on the common mounting substrate 65, the microcapsule 90 configured with an acoustically permeable mesh structure, the mounting substrate 65, and the mounting substrate 65. Elements (capacitive acoustoelectric conversion elements for converting sound into electric signals) 11a and 11b (the specific structure will be described with reference to FIG. 2) and output signals of the sound collecting elements 11a and 11b A signal processing unit (signal processing LSI) 62 that performs appropriate delay and addition / subtraction after conversion, and bonding wires 63a to 63d for electrically connecting the sound collection elements 11a and 11b and the signal processing unit 62, Have.

  Capacitive sound pickup elements (MEMS sound pickup elements) 11a and 11b manufactured using a silicon LSI microfabrication technique (MEMS technique) are processed in comparison with sound pickup elements manufactured by assembling mechanical parts. The accuracy is high, and the acoustoelectric conversion accuracy is high and stable. Utilizing this advantage, a microphone device (microphone module) is configured by housing sound pickup elements manufactured using two semiconductor manufacturing processes in a microphone capsule 90. However, if there are a plurality of acoustic paths from the sound source to each sound collecting element due to sound diffraction, it becomes difficult to form directivity, and therefore a micro-wall having a partition wall 68 for preventing the generation of acoustic paths due to diffraction. Capsule (casing) is adopted. Thereby, it is possible to realize highly accurate and stable directivity using one microphone module in which at least two sound pickup elements are housed in a capsule.

  Since the microcapsule is configured with an acoustically permeable mesh structure, the microphone device of the present invention has only P1 and P2 acoustic paths from the sound source 68 to the sound collection elements 11a and 11b, and a plurality of acoustic paths are provided. Does not occur. Therefore, an electric signal suitable for signal processing for providing directivity can be obtained from each sound collection element (11a, 11b).

According to the present invention, it is possible to obtain a small microphone module (microphone device) capable of collecting directional sound and stereo sound.
FIG. 2 is a cross-sectional view of the device for explaining the structure of the sound pickup element (MEMS sound pickup element) manufactured by the silicon LSI manufacturing process shown in FIG.

A configuration of the microphone device of the present embodiment will be described with reference to FIGS. 1 and 2 are cross-sectional views of the microphone device of the present embodiment.
The sound collection element 11a (the same applies to 11b) includes a semiconductor substrate 12 including a vibration plate 33 that vibrates according to a change in sound pressure due to sound waves, a back plate 13 that is disposed to face the vibration plate 33 with a gap 16 between them, A spacer (electrical insulating film) 14 provided between the semiconductor substrate 12 and the back plate 13, an electrode 17 provided on the semiconductor substrate 12, and an electrode 18 provided on the back plate 13 are provided. The back plate 13 is provided with a plurality of through holes 15.

  By using a conductive material (silicon) as the semiconductor substrate 12, electrical conduction between the electrode 17 provided on the semiconductor substrate 12 and the diaphragm 33 is ensured. Similarly, by using a conductive material (silicon) as the back plate 13, electrical continuity with the electrode 18 provided on the back plate 13 is ensured.

  The back plate 13 is made of conductive silicon (for example, silicon that has been subjected to a process for reducing resistance by ion implantation or the like). A silicon electret film (not shown) formed by electrically charging a silicon oxide film is provided on the surface of the back plate 13, thereby providing a DC bias circuit for biasing the capacitive transducer. It becomes unnecessary.

In order to relieve pressure generated by vibration of the silicon diaphragm 33, the back plate 13 is intentionally provided with a plurality of gaps for pressure relief, and has a net-like structure.
The silicon diaphragm 33 is formed, for example, by etching a part of the bottom of the silicon substrate 12 having a predetermined thickness to provide a recess. However, the present invention is not limited to this manufacturing method. For example, a new thin silicon film can be grown on the back surface of the silicon substrate 12 provided with the depressions to form the diaphragm 33.

  The silicon diaphragm 33 and the back plate 13 are arranged to face each other with a predetermined distance separated by a spacer 14 made of an electrically insulating film such as a silicon oxide film, and a gap is formed between the silicon diaphragm 33 and the back plate 13. Thus, a capacitive transducer for converting mechanical vibrations due to pressure waves and sound waves into electrical signals is formed.

  Capacitive sound pickup elements (MEMS sound pickup elements) 11a and 11b manufactured using a silicon LSI microfabrication technique (MEMS technique) are processed in comparison with sound pickup elements manufactured by assembling mechanical parts. The accuracy is high, and the acoustoelectric conversion accuracy is high and stable. Therefore, variation in sound collection accuracy between the two sound collection elements can be minimized, and good and stable directivity can be formed.

Next, a process until the structure of the microphone device of the present embodiment shown in FIG. 1 is found will be described with reference to FIGS.
FIG. 4 is a cross-sectional view of an example of the microphone device for explaining a process until the structure of the microphone device of the present embodiment shown in FIG. 1 is found. In FIG. 4, the same reference numerals are given to the portions common to FIGS. 1 and 2.
As shown in FIG. 4, the MEMS sound collecting elements 11a and 11b are mounted on a common mounting board 65, and each sound collecting element 11a and 11b has a microphone capsule 64 provided with one sound hole 71 in the center. It is covered in.

  FIGS. 5A and 5B are diagrams for explaining the process until the structure of the microphone device of the present embodiment shown in FIG. 1 is conceived (particularly, different acoustic paths are required for directional sound collection). It is sectional drawing which shows the positional relationship of a microphone apparatus and a sound source. In FIG. 5, the same reference numerals are given to portions common to FIGS. 1 and 2.

  As shown in FIGS. 5A and 5B, when there is one sound hole 71, acoustic paths (P3, P4) from any sound source 68a, 68b to each of the sound collection elements 11a, 11b. ) Cannot be given directivity to the sensitivity.

  FIGS. 6A and 6B are diagrams for explaining the process until the structure of the microphone device of the present embodiment shown in FIG. 1 is conceived (especially when an acoustic path is provided with a plurality of sound holes). FIG. 6 is a cross-sectional view showing the positional relationship between a microphone device and a sound source for explaining that it becomes difficult to collect directional sound due to complication of the sound. In FIG. 6, the same reference numerals are given to portions common to FIGS. 1 and 2.

  As shown in the figure, when a plurality of sound holes (73a, 73b) are provided in the microcapsule 64, there are a plurality of acoustic paths for reaching from the sound source 68 to each of the sound collecting elements 11a, 11b. That is, in the case of FIG. 6A, there are two acoustic paths P5 and P6, and in the case of FIG. 6B, there are two acoustic paths P7 and P8.

  Since different acoustic paths have different frequency characteristics and delay characteristics, the electrical signals output by the sound collection elements 11a and 11b are complicated, and an electrical signal suitable for signal processing for giving sensitivity directivity is collected. It cannot be obtained from the elements 11a and 11b.

  Under such consideration, returning to FIG. 1 again and analyzing the structure, the space in which each of the sound pickup elements 1a and 11b is located is hermetically separated by the partition wall 68 provided at the center of the microphone capsule 64. It can be seen that one sound hole 67a, 67b is provided for each space.

  With this structure, the sound that has passed through the sound holes (67a, 67b) for one sound collecting element is prevented from wrapping around and reaching the other sound collecting element due to diffraction, and the acoustic path (P1, P2). Can be unified. Accordingly, it is possible to appropriately set the delay amount and coefficient for directivity formation, and it is possible to form good directivity. The point that only one sound hole is provided for each space is advantageous in terms of maintaining the strength of the microcapsule 64 as a housing, maintaining a high electromagnetic shielding effect and a dustproof effect.

  As described above, in the microphone device of the present embodiment, the MEMS sound pickup elements manufactured using the MEMS technology and having high accuracy and excellent stability are accommodated in the capsule and arranged in parallel. By using a compact microphone module in which at least two sound pickup elements are housed in a capsule by unifying the acoustic path as a structure (acoustic transmission mesh structure) that prevents leakage of diffracted sound, High precision and stable directivity can be easily realized.

(Embodiment 2)
3A and 3B are a cross-sectional view and a process explanatory view showing another example of the microphone device of the present invention. In FIG. 3, parts that are the same as those described in the first embodiment are given the same reference numerals.
3 (a) and 3 (b) show an opening (particularly, a place necessary for making sound arrive at the diaphragms of the sound pickup elements 11a and 11b) of a metal microcapsule (housing) 64 ( 67c, 67d, 67e), and mesh sheets 91 and 92a, 92b are provided only at the openings. For example, the mesh sheets 91 and 92a and 92b are bonded to a metal microcapsule (housing) 64 using an adhesive.

  As the mesh sheets 91 and 92a, 92b, for example, coarse mesh sheets (fabrics) are used. As the coarse mesh sheet, a knitted mesh with stitches knitted with a conductive thread-like material, or a punching mesh sheet with fine small holes in a thin metal sheet can be used. As for roughness, 1 pitch width of about 0.5 mm to 5.0 mm is appropriate.

  In this way, by making at least a part of the microcapsule an acoustically transparent (acoustic transmission) mesh structure, the sound from the sound source goes straight as it is without being disturbed by the capsule of the microphone device. The sound collecting element is reached, and the acoustic path to one sound collecting element is unified.

  That is, also in the microphone device of the present embodiment, the acoustic path from the sound source 68 to each of the sound collection elements (11a, 11b) is a single straight line (P9, P10), as in the above-described embodiment. An electric signal suitable for signal processing for providing directivity can be obtained from the sound collection element, and the same effect as in the first embodiment can be obtained. That is, it is possible to appropriately set the delay amount and the coefficient for directivity formation, and it is possible to form good directivity. Moreover, the shielding effect of electromagnetic noise can be obtained by using a conductive mesh.

  In the above-described embodiment, the example in which the microphone device capable of directional sound collection and stereo sound collection is described using two sound collection elements is not limited to this. It is also possible to achieve higher directivity using the above sound pickup elements.

  In the microphone device using three or more sound pickup elements, the use of the mesh structure microphone capsule described in the first embodiment can simplify the structure and can be manufactured at low cost.

  As described above, according to the present invention, the MEMS sound pickup elements manufactured using the MEMS technology and having high accuracy and excellent stability are stored in the capsule in parallel, and the capsule is stored in the capsule. By using a compact microphone module in which at least two sound pickup elements are housed in a capsule by unifying the acoustic path as a structure that prevents diffracted sound from leaking (structure having an acoustically transparent mesh) Therefore, it is possible to easily realize highly accurate and stable directivity.

  In other words, the partition wall provided in the capsule hermetically separates the space where each of the first sound collection element and the second sound collection element is located, so that the sound that has passed through the sound hole for one of the sound collection elements. However, it is possible to prevent the sound collecting element from wrapping around and reaching the other sound collecting element by diffraction, and to integrate the acoustic path. Accordingly, it is possible to appropriately set the delay amount and coefficient for directivity formation, and it is possible to form good directivity.

Further, by making at least a part of the capsule an acoustically transparent (acoustic transmissive) mesh structure, the sound from the sound source goes straight as it is without being disturbed by the capsule of the microphone device, and each sound collecting element Therefore, the acoustic path to one sound collecting element is unified. Accordingly, it is possible to appropriately set the delay amount and coefficient for directivity formation, and it is possible to form good directivity.
Moreover, the shielding effect of electromagnetic noise can be obtained by using a conductive mesh.

  In the above embodiment, the sound pickup element chip and the signal processing circuit chip are formed by mounting on the substrate 65. However, in a state where the MEMS sound pickup elements having high precision and stability are arranged in parallel. LSI may be used. Furthermore, the acoustic path may be integrated as a structure that is housed in a microcapsule formed by the MEMS process and that the microcapsule prevents leakage of diffracted sound. In other words, as a structure to prevent leakage of diffractive sound, a silicon microcapsule formed by a MEMS process starting from the same silicon substrate as the LSI chip on which the first and second sound pickup elements and the signal processing circuit are mounted is adopted. May be.

In the above embodiment, an example in which a microphone device capable of directional sound collection and stereo sound collection using two sound collection elements has been described. However, the present invention is not limited to this. It is also possible to achieve higher directivity using the above sound pickup elements.
In the microphone device using three or more sound collection elements, the use of the microcapsule described in Embodiment 2 can simplify the structure and can be manufactured at low cost.

  As described above, according to the present invention, the MEMS sound pickup elements manufactured using the MEMS technology and having high accuracy and excellent stability are stored in the capsule in parallel, and the capsule is stored in the capsule. A compact structure in which at least two sound collecting elements are housed in a capsule by unifying the acoustic path as a structure that prevents leakage of diffracted sound (a structure having a partition wall that airtightly separates the sound collecting elements). Using the microphone module, highly accurate and stable directivity can be easily realized.

In addition, by accommodating the signal processing unit in the capsule, a microphone device in a single module capable of highly accurate and stable directional sound collection (including stereo sound collection) can be obtained.
Further, by mounting the sound collecting element and the signal processing unit on a common substrate and covering the substrate with a capsule to form one module, a compact one-module microphone device can be obtained.

  According to the present invention, it is possible to provide a microphone device capable of high-accuracy and stable directional sound collection and stereo sound collection with a small microphone device alone.

  The present invention has the effect of enabling highly accurate and stable directional sound collection and stereo sound collection with a small microphone device alone, and therefore, an ultra-small microphone device (for example, an ultra-small electret condenser microphone array). Module).

Sectional drawing which shows the microphone apparatus of Embodiment 1 of this invention. Sectional drawing of the device for demonstrating the structure of the sound collection element (MEMS sound collection element) manufactured by the manufacturing process of the silicon LSI shown by FIG. It is a figure which shows the microphone apparatus of Embodiment 2 of this invention, (a) (b) shows the variation (modification) of the structure of a microcapsule. Sectional drawing of an example of a microphone apparatus for demonstrating the process until the structure of the microphone apparatus of this Embodiment shown by FIG. 1 is devised. (A), (b) is for demonstrating the process until the structure of the microphone apparatus of this Embodiment shown in FIG. 1 is conceived (especially a different acoustic path is required for directional sound collection). Cross-sectional view showing the positional relationship between the microphone device and the sound source (A), (b) is a diagram for explaining the process until the structure of the microphone device of the present embodiment shown in FIG. 1 is conceived (particularly, when a plurality of sound holes are provided, the acoustic path is complicated). For explaining that it becomes difficult to collect directional sound), a sectional view showing the positional relationship between the microphone device and the sound source Sectional view showing the structure of a conventional example

Explanation of symbols

11a, 11b Sound collecting element 12 Silicon semiconductor substrate 13 Back plate 14 Spacer (electrical insulating film)
15 Air escape through hole 16 Gap 17, 18 Electrodes 32 a, 32 b First and second sound collecting elements 32 LSI
34 Silicon microcapsule 33 Diaphragm (for example, silicon diaphragm made of doped silicon)
63a to 63d Bonding wire 64 Microphone capsule (casing, casing)
67a, 67b Sound hole 68 Sound source

Claims (6)

First and second sound pickup elements manufactured using a semiconductor manufacturing process;
A signal processing unit that performs predetermined arithmetic processing based on output signals of the first and second sound pickup elements;
A microphone capsule disposed so as to cover the first and second sound collecting elements and the signal processing unit, and at least a part of which constitutes a sound-transmitting mesh structure unit;
A part of the sound from one sound source to the first sound collecting element is prevented from reaching the second sound collecting element by diffraction, and the sound from one sound source to the second sound collecting element A microphone device that prevents a part of the microphone from reaching the first sound collecting element due to diffraction. The microphone device according to claim 1, wherein
The acoustically permeable mesh structure is a microphone device made of a conductive material. The microphone device according to claim 1 or 2,
The microphone device in which the signal processing unit performs delay processing and addition / subtraction processing on the output signals of the first and second sound collection elements to realize directional sound collection. A microphone device according to any one of claims 1 to 3,
A microphone device in which the first and second sound collection elements and the signal processing unit are mounted on a common substrate. A microphone device according to any one of claims 1 to 3,
A microphone device in which the first and second sound collection elements and the signal processing unit are integrated on the same substrate. A microphone device according to any one of claims 1 to 5,
A microphone device in which the microphone capsule is formed by processing a semiconductor substrate by a MEMS process.

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