JP2003102097A - Sound processing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sound processing apparatus at a low cost with uniformized characteristics and enhanced reliability while attaining downsizing/ weight reduction and mass-productivity of a sound input section. SOLUTION: A chip microphone 10 with a layered structure by a semiconductor manufacturing technology and comprising a diaphragm 12 vibrated by a sound pressure, a rear plate 14 facing the diaphragm 12, and a joining support 13 joining the diaphragm 12 and the rear plate 14 to ensure a vibration space S of the diaphragm 12 and whose major component is silicon oxide powder is mounted on a sound recording device for performing recording processing of recording sound information such as picked up voice to a recording section 25.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sound processing device, and more particularly, to a device capable of miniaturizing a sound information input unit.

[0002]

2. Description of the Related Art Conventionally, sound processing devices such as portable recorders and mobile phones have been reduced in size and weight like other electronic devices. The microphone used in such a small sound processing device is mainly a condenser type,
It is composed of two plates, a diaphragm and a back plate.

This type of microphone is excellent in performance such as sensitivity and noise and is suitable for miniaturization. For example, a spacer (support portion) is interposed between the diaphragm and the back plate, and the microphone is attached to the case. It is mounted on a circuit board by mounting it on a circuit board and making it a module.

[0004]

However, such a conventional microphone has the following problems because it is manufactured by assembling a plurality of types of parts.

Since there is a limit to the miniaturization due to the restriction of the accuracy of the assembly process of parts, the thickness is smaller than that of other modules such as semiconductor parts mounted in small electronic devices such as mobile phones. The occupying area also becomes large, which is an obstacle to increasing the packaging density of the circuit board.

Further, when a component made of a resin material is used for the diaphragm, the spacer insulating portion, etc., deformation occurs due to thermal shock caused by a plurality of heat treatments (200 ° C. or more) such as soldering in the mounting process. There is a fear of bumps /
It is not possible to perform batch processing in a mounting process that involves high-temperature processing such as reflow, and thus efficiency cannot be achieved. Further, in the mounting process using the lead-free solder, resistance to heat treatment at a higher temperature of 240 to 260 ° C. is required.

Therefore, in order to solve the above problems, the present invention aims to reduce the size and weight of the sound input unit and to improve the mass productivity, and at the same time reduce the cost of the sound processing device and make the characteristics uniform. The purpose is to improve reliability.

[0008]

In order to solve the above problems, a microphone having a structure that can be manufactured by using a micromachining technique such as a semiconductor manufacturing technique is adopted to reduce the size and weight of a sound input unit. In addition, the sound input unit that does not require an assembly process and can be mass-produced, such as an LSI manufactured by a semiconductor manufacturing process, has been realized. Realization and improve reliability.

Here, the sound processing device means a device for processing sound information of a sound wave including a human voice (audible area and sound information outside the area), for example, a sound like a mobile phone. A device that processes information transmission, a device that records sound information on a medium such as a cassette tape or a memory chip, a device that recognizes voice, such as a personal computer, a voice device such as a hearing aid or a loudspeaker. Such as a device that amplifies sound information, a device that is equipped with a microphone, etc. to give feedback to the acoustic effect and sound field effect generated by itself, or a device that has a microphone, etc. A device for measuring the effect and the sound field effect may be used.

A first invention for solving the above-mentioned problems is a sound processing apparatus for acquiring sound information by a microphone and processing the sound information, wherein the microphone includes a diaphragm vibrating by sound pressure. A chip microphone provided with a rear plate facing the diaphragm and an adhesive layer for adhering the diaphragm and the rear plate to each other to secure a gap, wherein the adhesive layer is composed mainly of powdered silicon oxide. It is characterized in that the plate and the back plate are adhered to each other in a laminated structure.

According to the present invention, since the microphone is formed into a chip by forming it into a laminated structure in which the diaphragm and the back plate are adhered by the adhesive layer, it is possible to manufacture a small microphone with high precision by using the micromachining technique. You can
Further, in this chip microphone, since the adhesive layer is formed with powdered silicon oxide as a main component, the adhesive layer is deposited on the adhesive surface of the substrate serving as the vibrating plate or the substrate serving as the back plate. By heat-treating the two substrates together, the substrates can be easily bonded uniformly in the plane,
Further, an insulating layer having a desired thickness can be simultaneously formed between these substrates. At this time, since the adhesive layer is a powder, it is possible to completely fill the oxide and eliminate defects in the oxide film, and to perform the adhesion without requiring high level process control of the flatness and cleanliness of the adhesive surface. Is possible,
Furthermore, there is an advantage that the degree of freedom in designing the thickness of the substrate, the thickness of the insulating layer, etc. can be made much larger than that of the direct bonding or the conventional SOI (silicon on insulator) technology.

Further, since the vibration plate and the back plate are simply formed in a laminated structure in which they are adhered by an adhesive layer, the electrodes facing each other except the portion directly functioning as the vibration plate and the back plate are separated from each other. It is possible to adopt a structure having a level difference that allows the formation of a step. By adopting such a structure, it is possible to reduce the parasitic capacitance generated between the electrodes and improve the sensitivity.

A second invention for solving the above-mentioned problems is characterized in that, in addition to the particulars of the first invention, the chip microphone is manufactured by a semiconductor manufacturing technique.

In the present invention, since the chip microphone is manufactured by utilizing the semiconductor manufacturing technology of the micromachine processing technology, the chip microphone can be manufactured in a smaller size and with high accuracy. When a silicon-based material is used for the substrate, this chip microphone can be subjected to high-temperature heat treatment by utilizing the high heat resistance of the silicon-based material, such as reflow during microphone module fabrication or circuit board mounting described later. It is possible to improve the resistance to multiple thermal shocks. Therefore, it is possible to fabricate a chip microphone having a thickness as small as 1 mm or less and a small mounting area without using a process of assembling a plurality of parts, and a bump / reflow method or the like is used for a circuit board. The efficiency can be improved by adopting a mounting process involving high-temperature processing such as bulk mounting. Further, it is possible to prevent the usable temperature range from being narrowed by the sound information input unit. Note that the heat resistance of the chip microphone is 300 ° C or higher even when commonly used aluminum is used for the electrode, and due to the heat resistance of this level, the high temperature mounting process using lead-free solder is also applicable. You can Needless to say, this electrode material may be any material that has good ohmic contact with the substrate material such as silicon.

A third invention for solving the above-mentioned problems, in addition to the specific matters of the above-mentioned first or second invention, is characterized in that the adhesive layer is 1 μm.
It is characterized in that it is formed to a thickness of m to 20 μm.

According to the present invention, the diaphragm and the back plate can be bonded to each other with a thin adhesive layer, so that a small chip microphone can be obtained. The thickness of this adhesive layer is 2 μm
It is more preferable to set the thickness to ˜5 μm, and by setting the thickness to this, for example, a small chip microphone can be manufactured with high accuracy by a semiconductor manufacturing technique using a silicon-based material to have uniform characteristics.

In a fourth invention for solving the above-mentioned problems, in addition to the specific matters of the first to third inventions, the adhesive layer is a group IIIB element in the periodic table of elements such as boron and indium, Alternatively, it is characterized by containing one or more elements of VB group in the periodic table of elements such as phosphorus, arsenic and antimony in high concentration.

In the present invention, the fluidity of the insulating layer at the time of bonding is increased by incorporating an element of Group IIIB such as boron and an element of Group VB such as phosphorus into the adhesive layer containing powdered silicon oxide as a main component. Therefore, it is possible to improve the uniformity of adhesion between the substrate serving as the diaphragm and the substrate serving as the back plate.

A fifth invention for solving the above-mentioned problems is, in addition to the specific matters of the first to fourth inventions, a chip microphone as it is or a module in which the chip microphone is packaged, is provided on a circuit board. It is characterized by being implemented.

In the present invention, the chip microphone is mounted on the circuit board as it is or as a module, so that a high-density circuit structure can be obtained.

A sixth invention for solving the above-mentioned problems, in addition to the items specified in any one of the above-mentioned first to fifth inventions, relates to an LC circuit using the chip microphone as a capacitor and a change in the capacitor capacity of the chip microphone. And an output unit for reading out as a change in the oscillation frequency of the LC circuit.

According to the present invention, the vibration of the diaphragm of the chip microphone can be read as a change in the capacitance of the capacitor by applying a weak voltage in the LC circuit without applying a bias voltage as in a normal microphone. Further, the LC circuit including this chip microphone can be formed on the same substrate. Therefore, even if the adhesive layer is thinly formed to a thickness of 1 μm to 20 μm, it is possible to prevent the diaphragm and the back plate from sticking to each other due to the applied voltage, and the chip microphone and the entire device can be made smaller. be able to.

Furthermore, by providing a function of FM-modulating and transmitting a carrier wave that responds to a change in the condenser capacity of the chip microphone, the connection with the sound input section can be made wireless.

A seventh invention for solving the above-mentioned problems is, in addition to the particulars of the first to sixth inventions, an array microphone in which the chip microphones are arranged in an array, and a plurality of chip microphones in the array microphones. And a synchronous adder circuit for synchronously adding the outputs of the above. As an eighth invention for solving the above-mentioned problems,
In the array microphone, the chip microphones may be arranged in an array in one direction, and the array microphones may be further arranged in parallel.

In the present invention, the output of the chip microphone in the array microphone can be regarded as the same phase, and the noise can be reduced by the synchronous addition circuit. Therefore, it is possible to configure a sound input unit that is small and has less noise, and by integrally forming by a semiconductor manufacturing technology, a voice input unit with uniform characteristics for each chip microphone or each device can be manufactured with high precision and small size. can do.

A ninth invention for solving the above-mentioned problems, in addition to the items specified in the seventh or eighth invention, is provided with a plurality of the array microphones and the synchronous adder circuits, and is provided from the synchronous adder circuit for each array microphone. The present invention is characterized in that a directivity control circuit for processing the output to give directivity to the plurality of array microphones is provided.

According to the present invention, it is possible to obtain sound information with directivity provided by a plurality of array microphones. Therefore, for example, in a mobile phone having an image pickup function, it is possible to realize voice input from a separated position. In addition, by integrally forming by a semiconductor manufacturing technique, it is possible to make a voice input unit with uniform characteristics for each chip microphone and each device with high precision and small size.

[0028]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described below with reference to the drawings. 1 to 3 are diagrams showing an example of a voice recording device to which a first embodiment of a sound processing device according to the present invention is applied.

In FIG. 1, the voice recording device (sound processing device) performs a recording process of recording the sound information after the sound information such as a person's voice acquired by the chip microphone 10 is amplified by the amplifier 21. This chip microphone 10 and amplifier 2
The IC chip 20 is miniaturized by integrally forming (manufacturing) the IC chip 20 by a semiconductor manufacturing technology (micromachining technology) described later, and the IC chip 20 is also manufactured.
Is directly connected to the recording unit 25 so that the whole apparatus is compact.

As shown in FIG. 2, the chip microphone 10 includes a diaphragm 1 vibrated by sound pressure at the center of a base 11.
2, the adhesive supporting portion (adhesive insulating layer) 13 supports the back plate 14 around the diaphragm 12 so as to secure the vibration space (void layer) S thereof, and the diaphragm 12 faces the diaphragm 12. By forming counter electrodes on the diaphragm 12 and the back plate 14, it is constructed so as to function as a condenser microphone.
0 is the adhesive support 13 between the diaphragm 12 and the back plate 14.
The amplifier 21 having the laminated structure in which the
It is designed so that it can be manufactured by semiconductor manufacturing technology. In addition, the reference numeral 14a in the figure denotes the diaphragm 1.
2 is a plurality of through holes formed so that the front and back of the back plate 14 communicate with each other so as not to interfere with the vibration of 2.

As the IC chip 20, the diaphragm 1 is used according to the sound information input to the chip microphone 10.
The change of the capacitance generated between the counter electrode and the back plate 14 due to the vibration of the electrode 2 remains as an analog signal while the electrode terminal
It is taken out at 5, 16 and amplified by the amplifier 21 before being output.

The chip microphone 10 has a role of adjusting the acoustic characteristics of the microphone to the volume of the cap by attaching a cap so as to cover the back plate 14 and forming a gas flow hole in the center of the cap. The cap can be used as an electromagnetic wave shield, and the directivity of the microphone can be controlled by a gas flow hole in the center of the cap.

Next, the manufacturing procedure (method) of the chip microphone 10 by the semiconductor manufacturing technology will be described with reference to FIG. Since the amplifier 21 may be manufactured by a general semiconductor process, the description here is omitted.

First, as shown in FIG. 3A, for example,
A silicon substrate which is a general semiconductor substrate is prepared as a vibrating plate substrate 112 and a back plate substrate 114, and a surface of the vibrating plate substrate 112 to be bonded (bonded) to the back plate substrate 114 is powdered by a CVD technique or the like. An adhesion layer 113 containing silicon oxide as a main component and containing boron or phosphorus in a high concentration is deposited to a desired thickness, for example, 10 μm. In order to reduce the size of the microphone, the adhesive layer 113 is preferably 1 μm to 20 μm in terms of manufacturing surface and bias voltage. Further, in terms of sensitivity and frequency characteristics, the adhesive layer 113 has a thickness of 2 μm or more.
5 μm is more preferable, and it can be set according to the applied voltage so that the vibration plate 12 and the back plate 14 do not stick to each other. Also,
It goes without saying that the adhesive layer 113 may be formed on the rear plate substrate 114 side.

Next, as shown in FIG. 3 (b), the vibration plate substrate 112 and the back plate substrate 114 are heat-treated together to form the substrate 11 through the deposited adhesive layer 113.
After adhering between 2 and 114, the back plate 114 is polished to form a desired thickness for the back plate, and thereafter, an oxide film is heat-treated on both surfaces of these substrates 112 and 114. Then, an etching mask 117 is formed by processing the oxide film by photolithography.

Next, as shown in FIG. 3C, the substrates 112 and 114 are wet-etched using an alkaline etching solution using this etching mask 117, or, for example, dry etching is performed using XeF ₂ gas. By processing, the base 11 on which the vibration plate 12 is formed and the back plate 14 are formed. At this time, the back plate 14
Has a mesh structure in which a plurality of through holes 14a for releasing the pressure of the air generated in the vibration space S due to the vibration of the vibration plate 12 are formed in a portion other than the portion corresponding to the adhesive support portion 13.

Next, as shown in FIG. 3D, the back plate 14 is used as an etching mask, and the adhesive layer 113 is etched from the mesh structure of the back plate 14 with hydrofluoric acid, whereby the vibration plate 12 and The vibrating space S is formed by removing the adhesive layer 113, leaving a portion corresponding to the adhesive support portion 13 in the peripheral portion of the back plate 14, and thereafter, for example, a metal film of aluminum is vapor-deposited from the back plate 14 side to form electrodes. Terminal 1
An integrated chip microphone 10 forming 5 and 16
To make.

At this time, since the adhesive layer 113 contains powdered silicon oxide as a main component, it is possible to completely fill the oxide and prevent defects in the oxide film. Therefore, the substrate 112, Even if the flatness of 114 is not strictly controlled, in-plane uniform bonding can be performed in a short time, and furthermore, between the thick substrates 112 and 114 without requiring management of extremely high cleanliness of the bonded surface. Can be simultaneously and easily bonded. Therefore, the thickness of the substrates 112 and 114, the concentration distribution of impurities, the layer thickness of the adhesive layer 113 itself, and the like can be set more freely than in the case where the substrates 112 and 114 are directly bonded. Further, since the adhesive layer 113 contains boron or phosphorus in a high concentration, it is possible to increase the fluidity at the time of adhesion and improve the uniformity of the substrates 112 and 114 at the time of adhesion.

Then, the IC chip 20 connects the electrode terminals 15 and 16 of the chip microphone 10 and the input terminal of the amplifier 21 by a method such as wire bonding,
By connecting the output terminal of the amplifier 21 and the recording unit 25, it functions as an audio input unit of the audio recording device.

As described above, in the present embodiment, the chip microphone 10 has the adhesive support portion 13 which is interposed between the diaphragm 12 and the back plate 14 and has a laminated structure, which is composed mainly of powdered silicon oxide. In addition, a highly accurate chip component is manufactured inexpensively and easily by manufacturing the semiconductor manufacturing technique that does not require an assembling process so that boron or phosphorus is contained in a high concentration to a thickness of 1 μm to 20 μm. Therefore, a small microphone having uniform characteristics can be mass-produced at low cost.

Further, the chip microphone 10 is
Since the IC chip 20 is integrally formed with the amplifier 21, the quality is highly stable, and the size and weight can be more effectively realized.

Further, since the chip microphone 10 is made of a silicon material, it has high heat resistance, and it is possible to reduce the possibility that the usage range is limited by the operating temperature.

In this embodiment, the diaphragm 12, the adhesive support portion 13, the back plate 14 and the like are made of the same silicon-based material, but needless to say, the material is not limited to the silicon-based material.

As a first other aspect of this embodiment, for example, a chip microphone may be constructed as shown in FIG. The chip microphone 10 of the present embodiment
Is manufactured by bonding the flat substrates 112 and 114 to each other, the parasitic capacitance generated by the counter electrode formed around the portion functioning as the diaphragm 12 and the back plate 14 is about the same as the effective capacitance. This causes a decrease in sensitivity when detecting a capacitance change due to sound pressure. For this reason, rather than simply reducing the area of the corresponding part to lower the sensitivity (because the sensitivity of the microphone is proportional to the area of the corresponding part), as shown in FIG. 11 that raises the part that directly functions as
By forming a on the base 11 and forming a thicker adhesive support portion 17 around the adhesive support portion 13 as well, the space between the opposing electrodes is separated to reduce the parasitic capacitance and improve the sensitivity. You can

Further, as a second other aspect of the present embodiment, as shown in FIG. 5, in addition to the step 11a on the base 11 side, the rear plate 14 side also has a portion facing the diaphragm 12. By forming a step 14b that raises the periphery and forming a thicker adhesive support portion 19 around the adhesive support portion 13, the gap between the opposing electrodes is further separated, and the parasitic capacitance is further reduced to improve the sensitivity. Can be improved.

Next, FIG. 6 is a diagram showing an example of an audio recording / reproducing apparatus to which the second embodiment of the sound processing apparatus according to the present invention is applied. Since the present embodiment has substantially the same configuration as the above-described embodiments, the same reference numerals are given to the same configurations to describe the characteristic portions (the same applies to other embodiments described below). .

In FIG. 6, the audio recording / reproducing device (sound processing device) performs a recording / reproducing process for digitally recording and reproducing the sound information acquired by the chip microphone 10 of the IC chip 20 and amplified by the amplifier 21. Has become
The IC chip 20 includes an A / D converter 31 that converts an analog signal output from the amplifier 21 into a digital signal.
And an encoder 32 for compressing sound information by encoding the digital signal A / D converted by the A / D converter 31.
A recording unit 33 for recording (recording) sound information encoded by the encoder 32 on a recording medium such as a magneto-optical disk such as a memory stick or MO; and compressed sound information recorded in the recording unit 33. A decoder 34 for reading and decoding, a D / A converter 35 for converting the sound information of the digital signal decoded by the decoder 34 into an analog signal, and a D / A converter 3
Amplifier 3 that amplifies the analog signal D / A converted by 5.
6 and a speaker 37 that outputs and reproduces the sound information sent through the amplifier 36 as a sound, and is mounted (on-chip) on one circuit board 30. In addition, this I
It goes without saying that the C chip 20 may be mounted on the circuit board 30 as a packaged module by attaching the cap or the like.

Therefore, the microphones can be mounted on one circuit board 30 instead of being mounted separately, and the audio recording / reproducing apparatus can be assembled only by housing in the case. In the step of mounting on the circuit board 30, since the IC chip 20 is made of a silicon-based material, high temperature heat treatment can be performed by utilizing high heat resistance, and bump / reflow or the like accompanied by high temperature treatment is adopted. Then, they can be collectively mounted on the circuit board 30. Note that I
Since the C chip 20 has aluminum electrodes formed on the chip microphone 10, it can be applied to a high-temperature mounting process using lead-free solder.

As described above, in this embodiment, in addition to the effects of the above-described embodiment, the IC chip 20 is mounted on the circuit board 30 together with the other components 31 to 37. Therefore, for example, CSP (chip size packaging) As a result, high-density mounting can be performed, and the efficiency of the process of assembling the circuit board 30 can be realized, such as bulk mounting using bump / reflow. Therefore, it is possible to contribute to downsizing, cost reduction, and high reliability of the audio recording / reproducing apparatus.

Further, as another aspect of the present embodiment, as shown in FIG. 7, as in the above-described first embodiment, the component 31 is used.
It goes without saying that the IC chips 20 may be individually connected to the circuit board 30a on which the IC chips 20 to 37 are mounted by signal lines, as shown in FIG.
The D converter 31 is mounted on the circuit board 30b so as not to reduce the S / N ratio of the output of the sound information, or as shown in FIG. 9, the IC chip 20, the A / D converter 31 and the encoder 3 are used.
2 can be mounted on the circuit board 30c and the former stage of the recording unit 33 can be unitized to facilitate the assembly. These forms may be designed according to circumstances such as the external shape and function of the device and various processes.

Next, FIGS. 10 and 11 are views showing an example of a voice acquisition device to which the third embodiment of the sound processing device according to the present invention is applied.

In FIG. 10 and FIG. 11, the sound acquisition device (sound processing device) includes a diaphragm 12 formed on a base 11.
And a back plate 14 having a plurality of through holes 14a formed therein, the chip support microphone 40 is constructed so as to function as a capacitor-type microphone by interposing an adhesive support portion 13 therebetween.

Here, since the chip microphone 40 is a capacitor composed of the thin and flat diaphragm 12 and the back plate 14, the displacement of the diaphragm 12 caused by the sound pressure change due to the sound wave is sensitive as the capacitance change of the capacitor. To detect well, increase the bias voltage, diaphragm 1
The diaphragm 1 that reduces the distance between the back plate 14 and the back plate 14.
2 and the back plate 14 increase the electrode area, the vibration plate 12
There is a measure such as softening the material of the diaphragm (to reduce the stiffness of the diaphragm 12), but in this chip microphone 40, the diaphragm 12 and the back plate 14 are prevented from sticking to each other by electrostatic attraction. There is a need. As an index for operating the both electrodes of the vibration plate 12 and the back plate 14 without sticking, "design for miniaturization of directional condenser microphone" (Mikiguchi Mizoguchi, Vol. 31, No. 31, p593-601). (1975)) defines the stability μ obtained by the following equation (1), and is usually designed so that μ = 7.

[0054]

[Equation 1] According to the above equation (1), the measures for improving the sensitivity of the chip microphone 40 conflict with the improvement of stability, and in this chip microphone 40, the distance between the diaphragm 12 and the back plate 14 is increased. Has a limit of several μm, and thus there is a limit to increase the sensitivity.

From this fact, this voice acquisition device is
As a part or all of the capacitance of the capacitor of the transmission / modulation circuit 41 of the transmission circuit, the chip microphone 40 is directly connected via the signal line (without the amplifier as in the first embodiment described above), thereby vibrating. The fact that the capacitance of the capacitor between the opposing electrodes between the plate 12 and the back plate 14 changes according to sound information such as voice is acquired as a change in the transmission frequency of the LC circuit, and the output terminal of the transmission / modulation circuit 41 is acquired. It is possible to output to an external device connected to.

Here, the LC oscillating circuit is an oscillating circuit in which the oscillating frequency is determined by the coil and the capacitor, and a change in the capacitance of the capacitor can be detected as a change in the oscillating frequency. According to this method, the chip microphone is used. Since it is not necessary to apply a bias voltage to the capacitor section of 40, it is possible to increase the degree of freedom in selecting a measure for higher sensitivity. In this case, only a weak voltage necessary for the oscillation circuit of the oscillation / modulation circuit 41 to operate is applied to the capacitor portion of the chip microphone 40, which is much higher than the bias voltage of a normal microphone. Since a low voltage is sufficient, the stability μ of the above formula (1) can be made large, and the problem that the diaphragm 12 and the back plate 14 are attached can be made less likely to occur.

Specifically, the oscillation frequency f of a general LC oscillator circuit is determined by the following equation (2).

[0058]

[Equation 2] When the change in f caused by the sound pressure is Δf, it is expressed by the following equation (3). Therefore, as a method of increasing the frequency displacement Δf in order to improve the sensitivity, the above measures ~ are effective. I know there is.

[0059]

[Equation 3] Therefore, in the conventional condenser type microphone, the bias voltage Vb of several V is required in order to obtain the practical sensitivity, while in the chip microphone 40,
The oscillation circuit can be operated at 2V, and from the above formula (1), the stability μ can be increased from several times to several hundred times compared with the conventional microphone, and as a result, a measure for high sensitivity can be achieved. The freedom to choose can be greatly increased.

The transmitting / modulating circuit 41 functions as an LC oscillating circuit by vibrating the diaphragm 12 of the chip microphone 40 in response to a change in sound pressure with respect to the rear plate 14 and changing its capacitor capacity. The oscillation frequency f changes. This oscillation frequency f is determined by the above equation (2).

The chip microphone 40 and the transmission / modulation circuit (LC circuit) 41 may be connected and assembled as separate parts, or may be mounted on the same circuit board. They may be manufactured on the same semiconductor substrate.

As described above, in this embodiment, in addition to the effects of the above-described embodiment, the chip microphone 4
With respect to the vibration of the diaphragm 12 of 0, the transmitting / modulating circuit 41 only applies a weak voltage in the LC circuit, instead of applying the bias voltage Vb as in a normal microphone,
By changing the condenser capacity of the chip microphone 40, it is possible to read the sound information, which is the sound pressure change.

Therefore, even if the adhesive support portion 13 of the chip microphone 40 is formed to be thin, for example, 2 μm to 5 μm, the diaphragm 12 and the back plate 14 are affected by the applied voltage.
It is possible to eliminate the possibility that the sound will stick to the sound input unit, and it is possible to further reduce the size of the audio input unit including the chip microphone 40 and the entire device.

Next, FIG. 12 is a diagram showing an example of a voice transmission apparatus to which the fourth embodiment of the sound processing apparatus according to the present invention is applied.

In FIG. 12, in the voice transmission device (sound processing device), the chip microphone 40 is a transmitter / modulator circuit 41.
The transmitting / modulating circuit (LC circuit) 41 is connected to an antenna 52 for transmitting an electric wave into the air so that an external device can receive it by radio instead of the output terminal.

Since the transmission / modulation circuit 41 detects a change in the capacitance of the capacitor of the chip microphone 40 as a change in the oscillation frequency, the change in the transmission frequency is regarded as FM modulation of the carrier frequency, and the radio wave is transmitted via the antenna 52. Can be transmitted wirelessly, and can be demodulated to sound information by the external device side that receives it. Therefore, this audio transmission device can be used as a wireless microphone.

Here, the antenna 52 may be connected and assembled as a separate component from the chip microphone 40 and the transmission / modulation circuit 41, or mounted on the same circuit board, but as the coil antenna, the chip microphone 40 and the transmission are provided. It is preferable to manufacture the same on the same semiconductor substrate by the semiconductor manufacturing technique together with the / modulation circuit 41 because it can be compactly constructed.

As described above, in this embodiment, in addition to the effects of the above-described embodiment, the chip microphone 4 is used.
The sound information input from 0 can be wirelessly received by an external device and can be transmitted in the air, and can be used as a compact wireless microphone.

Next, FIGS. 13 to 18 are views showing an example of a voice transmission apparatus to which the fifth embodiment of the sound processing apparatus according to the present invention is applied.

13 to 15, the audio transmission device (sound processing device) is provided with an array microphone 61 in which a plurality of IC chips 20 are arrayed in a matrix, and an array microphone unit 60 arranged in parallel. Of I
For example, the mobile phone 100 is mounted so that the sound information acquired by the chip microphone 10 of the C chip 20 and amplified by the amplifier 21 is processed and wirelessly transmitted to an external device.

The array microphone unit 60 carries a camera 71 for photographing an image of a caller and the like, and image information acquired by the camera 71 together with sound information acquired by the array microphone unit 60 through an antenna (not shown). A transmitter 72 for wirelessly transmitting to the telephone and a receiver 73 for receiving sound information and image information transmitted from the other party's mobile phone.
And a speaker 7 that reproduces the received sound information and outputs the sound.
4 and a liquid crystal display 75 that reproduces and outputs the received image information, and is stored in the case of the mobile phone 100. It is needless to say that the layout of each component in FIG. 13 is merely shown for convenience of description and is designed according to the form of the device.

The array microphone unit 60 is a low-noise microphone for each array microphone 61 by synchronously adding individual sound information acquired by the chip microphones 10 of the n IC chips 20 and output from the amplifier 21. The synchronous adder circuit 62 is connected so as to form

Noise is independently acquired (input) in each of the array microphones 61, but if the amplitude characteristics of each noise are uniform, "a super-directional microphone using a two-dimensional digital filter". (Kanamori and others
Acoustical Society of Japan Material for Electroacoustic Research, EA91-84
As described in (1991)), the noise reduction effect N calculated by the following equation (4) is obtained by synchronously adding the n chip microphones 10 with the same weighting.
r can be obtained. Nr = 10 · log (n) [dB] (4)

For example, when the array microphone 61 is provided with 16 chip microphones 10, the sound information of the 16 chip microphones 10 is synchronously added to obtain the numerical value of the equation (4) shown in FIG. From the calculation result of Nr, it can be seen that a large noise reduction effect of about 12 dB can be obtained.

However, in order to carry out the synchronous addition of the sound information by the array microphone 61, it is necessary to regard the outputs from the respective chip microphones 10 as being in phase, and for that purpose, the array microphones are compared with the wavelengths to be picked up. The size of the microphone 61 must be small enough. That is, in the array microphone 61, the size L on one side is approximately 1/10 of the wavelength.
In the following cases, since it can be considered that the respective chip microphones 10 are driven in the same phase by sound waves, the array microphone 61 is used by using the upper limit frequency f _h and the sound velocity c of the band in which noise can be reduced by synchronous addition. The size L is subject to the constraint of the following equation (5).

[0076]

[Equation 4] In order to arrange the 16 chip microphones 10 in a matrix in the array microphone 61, when the sound velocity c is 340 m / sec in the above formula (5),
As shown in FIG. 17, the range allowed as the size L is the area under the curve indicated by the diagonal lines in the figure, and assuming that the upper limit frequency f _{h of the} band capable of reducing noise is 8 kHz,
The upper limit of the size L is about 4 mm square, and the individual size of the chip microphone 10 is at most about 1 mm. Since the chip microphone 10 is manufactured by the semiconductor manufacturing technique, it has a size that can be manufactured.

The array microphone unit 60
Since a plurality of array microphones 61 are further arranged in parallel to form an array, the array microphones 61 are connected to the directivity control circuit 63 and noise is reduced by synchronously adding each array microphone 61 from each array microphone 61. By inputting output (sound information) and performing directivity processing, which is a known technique,
It is designed to form a super directional microphone. Note that this directivity processing (known art) is described in detail in the above-referenced "superdirective microphone using a two-dimensional digital filter".

Here, the array microphone unit 60 further arranges six sets of array microphones 61 in which the chip microphones 10 are arranged in a matrix in an array.
Each of the array microphones 61 has a synchronous addition circuit 62.
Are arranged adjacent to each other and connected, and the connection circuit configuration in which the output from the synchronous addition circuit 62 is integrated in the directivity control circuit 63 is formed on a single substrate 64 by using a micromachining technology that makes full use of semiconductor control technology. It can be manufactured with high accuracy, and the characteristics of the chip microphone 10 and the like can be made uniform and processed. Reference numeral 64 in FIG. 14 is a cover case of the array microphone unit 60.

Therefore, by mounting the small-sized array microphone unit 60, the mobile phone 100 can be operated as shown in FIG.
As shown in FIG. 8, for example, the camera 7 of the destination mobile phone
While displaying the face of the person to be photographed in 1 on the display 75 for confirmation, the voice uttered from the mouth separated from the array microphone unit 60 is acquired and input by the superdirectivity of the array microphone unit 60, It can be transmitted to the other party's mobile phone, and a comfortable conversation can be realized without the need to wear a special microphone.

Of course, what is displayed on the display 75 need not be the face of the other party, and may be characters, figures, images acquired through means such as broadcasting or the Internet.
Since it can be used without displaying anything, it goes without saying that it is possible to have a conversation with a partner who does not have a camera.

As described above, in this embodiment, in addition to the effects of the above-described embodiment, the array microphone unit 60 includes the synchronous addition circuit 62 and the directivity control circuit 63 together with the plurality of chip microphones 10 and the amplifier 21 in the semiconductor. The chip microphone 10 that can be integrally formed with high precision and small size by manufacturing technology and has uniform individual characteristics, and the synchronous addition circuit 62 and the directivity control circuit 6 are provided.
An excellent directional microphone can be configured by including 3. Also, this array microphone unit 6
0 can also be mass-produced at low cost by semiconductor manufacturing technology.

In the present embodiment, the super directional microphone has been described. However, by changing the processing characteristics of the directivity control circuit 63, the microphone can freely change its directivity from super directivity to omni directivity. It goes without saying that you can do it.

[0083]

According to the present invention, since the microphone to be mounted is formed into a chip by forming a laminated structure in which the diaphragm and the back plate are adhered by the adhesive layer, a compact and lightweight voice input section can be obtained. Since the adhesive layer contains powdery silicon oxide as a main component, the diaphragm and the back plate can be evenly bonded in-plane by the adhesive layer having a desired thickness and having no defects. In addition, by using micromachining technology such as semiconductor manufacturing technology, it is possible to efficiently manufacture a smaller and lighter microphone that has a wide operating temperature range, high accuracy, and uniform characteristics. By including an element such as group III boron or group V phosphorus in the adhesive layer containing silicon as a main component, the diaphragm and the back plate can be bonded more uniformly. Then, by mounting such a chip microphone as it is or as a module on a circuit board, the circuit board on which the microphones are mounted at high density can be mounted on the sound processing device. Therefore, a small-sized sound processing device having excellent characteristics and high reliability can be provided at low cost.

Further, by mounting an LC circuit using the chip microphone as a capacitor, the vibration of the diaphragm of the chip microphone is changed as the change of the oscillation frequency of the LC circuit due to the change of the capacitance of the chip microphone only by applying a weak voltage. Since it is a small chip microphone that can output and has a thin adhesive layer, the diaphragm and the back plate do not stick to each other due to the application of the bias voltage,
Sound information can be acquired.

Also, the noise information is reduced by synchronously adding the outputs of the chip microphones arranged in the array, or the noise information is reduced after the outputs of the chip microphones arrayed for each of a plurality of array microphones are synchronously added to reduce the noise. By performing the processing that gives directionality to the input of
It is possible to configure a sound input unit that is small and has directivity,
It is possible to realize a sound processing device that does not require a microphone to be brought close to the mouth.

[Brief description of drawings]

FIG. 1 is a diagram showing a first embodiment of a sound processing device according to the present invention, and is a conceptual block diagram showing a schematic configuration thereof.

2A and 2B are diagrams showing a configuration of a main part thereof, in which FIG. 2A is a plan view thereof, and FIG. 2B is a partial sectional side view thereof.

FIG. 3 is a process drawing for explaining the production of the relevant part.

FIG. 4 is a partial cross-sectional side view showing another aspect.

FIG. 5 is a partial cross-sectional side view showing another aspect.

FIG. 6 is a diagram showing a second embodiment of the sound processing device according to the present invention, and is a block diagram showing a schematic configuration thereof.

FIG. 7 is a block diagram showing another aspect.

FIG. 8 is a block diagram showing another aspect.

FIG. 9 is a block diagram showing another aspect.

FIG. 10 is a diagram showing a third embodiment of the sound processing device according to the present invention, and is a block diagram showing a schematic configuration thereof.

FIG. 11 is a partial cross-sectional side view showing the configuration of the main part thereof.

FIG. 12 is a diagram showing a fourth embodiment of the sound processing device according to the present invention, and is a block diagram showing a schematic configuration thereof.

FIG. 13 is a diagram showing a fifth embodiment of a sound processing device according to the invention, and is a block diagram showing a schematic configuration thereof.

FIG. 14 is a perspective view showing essential parts thereof.

FIG. 15 is a block diagram showing a configuration of essential parts thereof.

FIG. 16 is a graph illustrating characteristics of essential parts.

FIG. 17 is a graph illustrating the configuration of the main parts.

FIG. 18 is an explanatory diagram illustrating its use.

[Explanation of symbols]

10, 40-chip microphone 12 diaphragm 13 Adhesive support 14 Back plate 20 IC chip 21 Amplifier 25, 33 recording section 30, 30a to 30c Circuit board 31 A / D converter 32 encoder 34 Decoder 35 D / A converter 36 amplifier 37 speakers 41 Transmitter / Modulator 52 antenna 60 array microphone unit 61 array microphone 62 Synchronous adder 63 Directional control circuit 64 substrates 71 camera 72 Transmitter 73 Receiver 74 speakers 75 LCD 75 indicator 100 mobile phones

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H04R 1/40 320 H04R 1/40 320B 31/00 31/00 C (72) Inventor Toshifumi Tajima Setagaya, Tokyo 1-10-11 Kukina, Japan Broadcasting Corporation Broadcast Technology Institute F-term (reference) 4J040 DN071 EL051 HA016 HA136 HA266 HA306 HA326 KA42 5D017 BD04 BD07 5D018 BB22 BB25 5D021 CC15 CC19 CC20

Claims (9)

[Claims] 1. A sound processing device for acquiring sound information with a microphone and processing the sound information, wherein the microphone includes a diaphragm vibrating by sound pressure, and a back plate facing the diaphragm. It is configured by a chip microphone including an adhesive layer that adheres the diaphragm and the back plate to secure a gap, and the adhesive layer is composed of powder silicon oxide as a main component, and the diaphragm and the back plate are bonded to a laminated structure Sound processing device characterized by. 2. The sound processing device according to claim 1, wherein the chip microphone is manufactured by a semiconductor manufacturing technique. 3. The sound processing device according to claim 1, wherein the adhesive layer is formed to have a thickness of 1 μm to 20 μm. 4. The adhesive layer contains a high concentration of one or more elements selected from the group consisting of boron, indium, phosphorus, arsenic and antimony.
The sound processing device according to any one of 1 to 3. 5. The sound processing device according to claim 1, wherein the chip microphone is mounted on a circuit board as it is or as a module in which the chip microphone is packaged. 6. An LC circuit using the chip microphone as a capacitor, and output means for reading out a change in the capacitor capacity of the chip microphone as a change in the oscillation frequency of the LC circuit. The sound processing device according to any one of 1. 7. An array microphone in which the chip microphones are arranged in an array, and a synchronous adder circuit for synchronously adding the outputs of a plurality of chip microphones in the array microphone. The sound processing device according to Crab. 8. The sound processing apparatus according to claim 7, wherein the array microphone has chip microphones arranged in an array in one direction and further arrayed so that the array arrangements are arranged in parallel. 9. A directivity control circuit comprising a plurality of said array microphones and a synchronous adder circuit, and processing an output from said synchronous adder circuit for each array microphone to give directivity to said plurality of array microphones. The sound processing device according to claim 7, wherein the sound processing device is a sound processing device.