JP2010151531A - Sound pressure space differential detection sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sound pressure spatial differential detection sensor that can be miniaturized.
SOLUTION: Two diaphragms 1 each having a flat rectangular parallelepiped shape and arranged in a direction in which thickness directions are aligned with each other and their longitudinal directions are orthogonal to each other, and the diaphragm 1 is sandwiched between both sides in a short direction. A package 2 having a sandwiching portion 20 for each diaphragm 1 with a gap between them, and two each of the diaphragms 1 provided at the center of the diaphragm 1 in the longitudinal direction and one end in the lateral direction. Displacement detecting means (not shown) for detecting displacement in the thickness direction at the support 3 laid between the sandwiched portions 20 of the package 2 and the measurement points A to D at both ends in the longitudinal direction of each diaphragm 1. Z)). Since the sound pressure spatial differential in one direction can be detected for one diaphragm 1, the size can be reduced as compared with the case where a plurality of diaphragms are used to detect the sound pressure spatial differential in one direction.
[Selection] Figure 1

Description

  The present invention relates to a sound pressure spatial differential detection sensor.

  Conventionally, the sound pressure at a predetermined point (hereinafter referred to as “target point”) obtained from the sound pressure measured at each of a plurality of points, and the two axial directions of the sound pressure at the target point, respectively. Technology for sound source localization and noise removal by the spatiotemporal gradient method using the spatial gradient of the sound (sound pressure spatial differentiation) and the temporal gradient of the sound pressure at the target point (sound pressure temporal differentiation) (for example, patent literature) 1) is known.

In addition, by using the fact that the sound pressure attenuation width per unit distance is larger as it is closer to the sound source, by taking the difference between the sound pressures measured at two different measurement points at different distances from the target sound source, There is also known a technique (for example, see Patent Documents 2 to 4) that suppresses sound from a noise source farther from each measurement point than the target sound source and obtains sound pressure in which the sound from the target sound source is emphasized.
JP 2006-58395 A JP 2007-221651 A JP 2008-131474 A JP 2008-154224 A

  Conventionally, in the spatiotemporal gradient method as described above, a sound pressure spatial differential detection sensor made up of a total of four microphones arranged in a lattice in two rows in the two-axis direction has been used.

  In addition, in the apparatus that performs sound source localization and noise removal as described above, the structure of the sound pressure spatial differential detection sensor has been studied in order to improve accuracy and reduce the size.

  The present invention has been made in view of the above-mentioned reasons, and an object thereof is to provide a sound pressure spatial differential detection sensor that can be miniaturized.

  According to the first aspect of the present invention, at least one diaphragm having a flat rectangular parallelepiped shape made of an elastic material and a sandwiching part that sandwiches the diaphragm from both sides in the lateral direction with a gap between the diaphragms are provided for each diaphragm. Each of the packages and two each provided on each diaphragm are made of an elastic material and have a flat shape with the thickness direction oriented in the thickness direction of the diaphragm, and are short at the longitudinal center of the diaphragm. A support body having one end connected to one end in the hand direction and the other end connected to a sandwiching portion of the package, and a displacement detection means for detecting displacement in the thickness direction at both ends in the longitudinal direction of each diaphragm. It is characterized by that.

  According to this invention, it is possible to detect a sound pressure spatial differential in one direction per diaphragm, so that a plurality of diaphragms are used in order to detect a sound pressure spatial differential in one direction. Miniaturization can be achieved.

  According to a second aspect of the present invention, there is provided a flat rectangular parallelepiped-shaped diaphragm made of an elastic material, and a sandwiching portion for sandwiching the diaphragm from both sides in the lateral direction with respect to each diaphragm. Each of the packages and two each provided on each diaphragm are made of an elastic material and have a flat shape with the thickness direction oriented in the thickness direction of the diaphragm, and are short at the longitudinal center of the diaphragm. One end is connected to each end in the hand direction, and the other end is connected to a sandwiching portion of the package, and each support is provided with strain detection means for detecting strain caused by tension and torsion. .

  According to a third aspect of the present invention, there is provided a flat rectangular parallelepiped-shaped diaphragm made of an elastic material, and a sandwiching portion for sandwiching the diaphragm from both sides in the short-side direction with respect to each diaphragm. Each package, a package cover having a cavity in which each diaphragm is accommodated, and two each of the diaphragms made of an elastic material with the thickness direction oriented in the thickness direction of the diaphragm A support having a flat shape and one end connected to one end in the lateral direction at the center of the diaphragm in the longitudinal direction and the other end connected to the sandwiched portion of the package, and both ends in the longitudinal direction of each diaphragm And a displacement detecting means for detecting a displacement in the thickness direction.

  According to a fourth aspect of the present invention, in any one of the first to third aspects, in each support body, the width dimension of the other end connected to the package is larger than the width dimension of the one end connected to the diaphragm. It is characterized by being made small.

  According to the present invention, the frequency band of the detectable sound is widened as compared with the case where the width dimension of the other end connected to the package in each support is equal to or larger than the width dimension of the one end connected to the diaphragm. In addition, it is possible to enhance the anti-phase vibration, which is the vibration of the diaphragm such that the support is twisted, and to accurately detect the sound pressure spatial differential.

  According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the thickness dimension of each support is made smaller than the thickness dimension of the connected diaphragm.

  According to the present invention, compared to the case where the thickness dimension of each support is equal to or greater than the thickness dimension of the diaphragm, the detectable frequency band of sound can be widened, and the support can be twisted. It is possible to enhance the anti-phase vibration, which is the vibration of the diaphragm, and to design the sound pressure space differential with high accuracy.

  The invention of claim 6 is characterized in that, in any one of the inventions of claims 1 to 5, each support is made of a material having a Young's modulus lower than the material of the connected vibration parts.

  According to the present invention, compared to the case where the Young's modulus of the material of each support is equal to or greater than the Young's modulus of the material of the diaphragm, the detectable sound frequency band can be widened, and the support is twisted. It is possible to design such that the anti-phase vibration, which is the vibration of the diaphragm, is emphasized and the sound pressure spatial differential is detected with high accuracy.

  The invention of claim 7 is the invention according to any one of claims 1 to 6, wherein two sets of the diaphragm, the support and the sandwiching portion are aligned, the thickness direction of the diaphragm is aligned, and the longitudinal directions of the diaphragm are orthogonal to each other It is provided in the direction.

  According to the present invention, the sound pressure spatial differentiation can be obtained for each of the diaphragms that is parallel to the longitudinal direction of the two axial directions orthogonal to the thickness direction.

  According to the first to third aspects of the invention, it is possible to detect a sound pressure spatial differential in one direction for each diaphragm, and therefore, a plurality of vibrations are detected in order to detect a sound pressure spatial differential in one direction. The size can be reduced as compared with the case of using a plate.

  According to the invention of claim 4, in each support body, the width dimension of the other end connected to the package is made smaller than the width dimension of the one end connected to the diaphragm. Compared with the case where the width dimension of the other end connected to the package is equal to or larger than the width dimension of the one end connected to the diaphragm, the frequency band of the detectable sound can be widened, and the support can be twisted. It is possible to design to accurately detect the sound pressure spatial differential by emphasizing anti-phase vibration, which is the vibration of a simple diaphragm.

  According to the invention of claim 5, since the thickness dimension of each support is smaller than the thickness dimension of the connected diaphragm, the thickness dimension of each support is the thickness of the diaphragm. Compared with the case where the size is larger than the size, the frequency band of the detectable sound can be widened, and the anti-phase vibration, which is the vibration of the diaphragm that twists the support, is emphasized, and the sound pressure spatial differentiation is accurately performed. Design to detect is possible.

  According to the invention of claim 6, since each support is made of a material having a lower Young's modulus than the material of the connected vibration parts, the Young's modulus of the material of each support is equal to or greater than the Young's modulus of the material of the diaphragm. Compared to the case, the frequency band of the detectable sound can be widened, and the anti-phase vibration, which is the vibration of the diaphragm that twists the support, is emphasized, and the sound pressure spatial differential is detected with high accuracy. Design is possible.

  According to the seventh aspect of the present invention, two sets of the diaphragm, the support, and the sandwiching portion are provided in the direction in which the thickness direction of the diaphragm is aligned and the longitudinal directions of the diaphragm are orthogonal to each other. The sound pressure space differential is obtained for each of the two parallel directions in the longitudinal direction of the two axial directions orthogonal to the thickness direction.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  In the present embodiment, as shown in FIG. 1, two diaphragms 1 each having a flat rectangular parallelepiped shape made of an elastic material and arranged in a direction in which the thickness directions are aligned with each other and the longitudinal directions are orthogonal to each other. And a package 2 having each sandwiching portion 20 for sandwiching the diaphragm 1 from both sides in the short direction with respect to each diaphragm 1, and two each of the diaphragms 1 provided with an elastic material. It is a flat rectangular parallelepiped shape with the thickness direction facing the thickness direction of the diaphragm 1, and one end is connected to one end in the short direction at the center of the longitudinal direction of the diaphragm 1, and the other end is sandwiched between the packages 2. And a support 3 connected to the portion 20. The package 2 has a shape that surrounds each diaphragm 1 when viewed from the thickness direction of each diaphragm 1 and constitutes each sandwiching portion 20, and a front surface of the frame 21 (sounds relative to the diaphragm 1). The cover 22 is fixed to the surface on the side where the light enters. The cover 22 is provided with two rectangular sound holes 22 a corresponding to the diaphragm 1 on a one-to-one basis and allowing sound incident on the diaphragm 1 to pass therethrough. Here, it is assumed that the dimensional shape of the sound hole 22a is as close as possible to the dimensional shape of the diaphragm 1, and that the gap between the diaphragm 1 and the frame 21 is not exposed from the sound hole 22a when viewed from the front. This is desirable in order to prevent the sound from wrapping behind the diaphragm 1 as shown by the arrow in FIG. In the package 2 as described above, the frame 21, each diaphragm 1, and each support 3 can be formed as one component by performing a known semiconductor process on one semiconductor wafer. it can.

  Further, in the present embodiment, displacement detection that detects displacement in the thickness direction (hereinafter simply referred to as “displacement”) at each of measurement points A to D provided at both ends in the longitudinal direction of each diaphragm 1. Means (not shown). As the displacement detecting means, for example, one electrode is provided at the measurement points A to D of the vibration plate 1 and the other electrode is provided at a position facing the measurement points A to D in the package 2 to measure the vibration part 1. A capacitor whose capacitance changes with the displacement of points A to D, or a piezoelectric element that detects strain (that is, converts into an electric signal) generated in the diaphragm 1 or the support 3 can be used. More specifically, for example, as shown in FIG. 4A, one piezoresistor 4 a to 4 d is provided on each of the front and rear surfaces (that is, the thickness direction) of each support 3 to twist the support 3. 4 (b), and piezoresistors 4e to 4h are provided on one of the front and rear surfaces (front surface in the figure) of each support 3 as shown in FIG. Two vertical lines arranged in the protruding direction may be provided to detect the vertical strain due to the tension of the support 3.

By the way, the vibration of the diaphragm 1 in the present embodiment is a vibration in which the diaphragm 1 is rotated by the torsion of the support 3 as shown in FIG. 5A (hereinafter referred to as “reverse phase vibration”). FIG. 5B is a combination of vibrations caused by elastic deformation of the diaphragm 1 itself (hereinafter referred to as “in-phase vibration”). The antiphase vibration is a component that is anti-symmetric with respect to the longitudinal center of the diaphragm 1, and the in-phase vibration is a component that is symmetric with respect to the longitudinal center of the diaphragm 1. For example, the longitudinal direction of the respective measuring points symmetrical two points with respect to the center A of the diaphragm 1, and B, the displacement of the measurement point A z _A Distant, when the displacement of the measurement point B is denoted by z _B, each measurement point For A and B, the component due to the in-phase vibration of the displacements z _A and z _B is expressed as (z _A + z _B ) / 2, and the magnitude of the component due to the anti-phase vibration is expressed as | z _A −z _B | / 2. Is done. The arrangement of the piezoresistors 4a to 4d as shown in FIG. 4A is suitable for detecting antiphase vibration, and the arrangement of the piezoresistors 4e to 4h as shown in FIG. 4B is suitable for detecting inphase vibration. In the present embodiment, as shown in FIG. 6, the frequency band between the primary resonance frequency f1 that is the resonance frequency of the antiphase vibration and the secondary resonance frequency f2 that is the resonance frequency of the inphase vibration (hereinafter referred to as “resonance frequency f2”). It is simply called “frequency band”). That is, in order to widen the frequency band, it is desirable that the difference between the primary resonance frequency f1 and the secondary resonance frequency f2 is large.

  Here, the secondary resonance frequency f <b> 2 depends on the shape of the diaphragm 1 and the Young's modulus of the material of the diaphragm 1, and hardly changes depending on the change in the material and shape of the support 3. That is, if the primary resonance frequency f1 is lowered by changing the material and shape of the support 3, the difference between the secondary resonance frequency f2 and the primary resonance frequency f1 is increased, so that the frequency band can be widened. .

  The primary resonance frequency f1 is expressed by the following equation using the torsion spring constant (hereinafter, simply referred to as “torsion spring constant”) k of the support 3 and the inertia moment I of the diaphragm 1. Is done.

すなわち、１次共振周波数ｆ１を低くするには、ねじりばね定数ｋを小さくすればよい。ここで、図７に示すように、振動板１について、長さ寸法（長手方向の寸法）をＬ、幅寸法（短手方向の寸法）をＷ、厚さ寸法をＨとおき、振動板１の材料の密度をρとおくと、上記の慣性モーメントＩは、次式で表される。

That is, to lower the primary resonance frequency f1, the torsion spring constant k may be reduced. Here, as shown in FIG. 7, regarding the diaphragm 1, the length dimension (longitudinal dimension) is L, the width dimension (short dimension) is W, and the thickness dimension is H. When the density of the material is ρ, the above moment of inertia I is expressed by the following equation.

さらに、図７に示すように、支持体３について、長さ寸法（振動板１に対する連結部と挟み部２０に対する連結部との距離）をｂ、幅寸法（断面の長辺の長さ）をａ、厚さ寸法（断面の短辺の長さ）をｈとおくと、ねじりばね定数ｋは、支持体３の剛性率Ｇを用いて、次式で表される。

Further, as shown in FIG. 7, for the support body 3, the length dimension (distance between the coupling portion with respect to the diaphragm 1 and the coupling portion with respect to the sandwiching portion 20) is b, and the width dimension (long side length of the cross section) is. If a and the thickness dimension (the length of the short side of the cross section) are h, the torsion spring constant k is expressed by the following equation using the rigidity G of the support 3.

上式からもわかるように、支持体３のねじりばね定数ｋは、支持体３の断面の寸法a，hを小さくすることや、支持体３の材料の剛性率Ｇを小さくすることによって小さくすることができる。

As can be seen from the above equation, the torsion spring constant k of the support 3 is reduced by reducing the cross-sectional dimensions a and h of the support 3 or by reducing the rigidity G of the material of the support 3. be able to.

On the other hand, when the diaphragm 1 is considered that the fixed ends of two cantilever beams each having a length of L / 2 are connected to each other, the cross-sectional secondary moments of these cantilever beams are each (WH ³ / 12). Further, when the Young's modulus of the diaphragm 1 is Em, the secondary resonance frequency f2 is expressed by the following equation.

ただし、上記の式では振動板１と支持体３との連結部の面積による影響を無視しているが、振動板１と支持体３との連結部の面積が大きくなれば支持体３の連結部付近で振動板１が撓みにくくなることにより２次共振周波数ｆ２は高くなる。

However, in the above formula, the influence of the area of the connecting portion between the diaphragm 1 and the support 3 is ignored. However, if the area of the connecting portion between the diaphragm 1 and the support 3 is increased, the connection of the support 3 is increased. The secondary resonance frequency f <b> 2 increases as the vibration plate 1 becomes difficult to bend near the portion.

  In order to reduce the torsion spring constant k, lower the primary resonance frequency f1, and widen the frequency band, when considering reducing the width dimension a of the support 3, the diaphragm 1 and the support are as described above. If the area of the connection part with 3 becomes small, the restraint with respect to the diaphragm 1 will weaken, and the secondary resonance frequency f2 will become low. Therefore, in order to increase the frequency band by lowering the primary resonance frequency f1 while suppressing the decrease in the secondary resonance frequency f2, as shown in FIGS. It is desirable to make the width dimension a1 of the connecting part to the sandwiching part 20 smaller than the width dimension a2 of the connecting part to the diaphragm 1. In this case, the support 3 does not have a rectangular parallelepiped shape, but the cross-sectional shape in a cross section orthogonal to the length direction of the support 3 is a rectangular shape everywhere. If the width a2 of the connecting portion with respect to the diaphragm 1 is constant, as shown in FIG. 9, the secondary resonance frequency f2 and the primary resonance frequency f1 are reduced as the width dimension a1 of the connecting portion with respect to the sandwiching portion 20 is decreased. The frequency difference can be increased to widen the frequency band. In the support 3, a portion (hereinafter referred to as “throttle portion”) having a width dimension smaller than both of the width dimensions a 1 and a 2 at both ends in the length direction is provided in the center portion in the length direction. Even in this case, the frequency band can be widened as the width dimension of the aperture is reduced.

  Further, as a method of reducing the torsion spring constant k, there is a method of making the thickness dimension h of the support 3 smaller than the thickness dimension H of the diaphragm 1 as shown in FIG. Even with this method, the primary resonance frequency f1 can be lowered to widen the frequency band.

  Further, as a method of lowering the primary resonance frequency f1, there is a method of lowering the rigidity G of the material of the support body 3. The rigidity G is expressed by the following equation using Young's modulus E and Poisson's ratio γ.

振動板１と支持体３を互いに異なる材料で構成し、支持体３の材料のヤング率Ｅを低く（つまり剛性率Ｇを低く）すれば、２次共振周波数ｆ２にほとんど影響を与えることなく１次共振周波数ｆ１を低くして周波数帯域を広くすることができる。パッケージ２において挟み部２０を構成するフレーム２１と振動板１と支持体３とをそれぞれ半導体プロセスを用いて形成する場合において、上記のように振動板１と支持体３とのヤング率Ｅｍ，Ｅを互いに異ならせる方法としては、例えば、シリコンウェハの一面上にポリイミドの層を形成し、振動板１とフレーム２１との間となる部位のシリコンを除去するとともに、振動板１とフレーム２１との間となる部位であって支持体３となる部位以外のポリイミドを除去するという方法がある。すなわち、振動板１とパッケージ２のフレーム２１とはそれぞれシリコンの層とポリイミドの層とで構成され、支持体３はポリイミドの層のみで構成されることになるから、支持体３のヤング率Ｅを振動板１のヤング率Ｅｍよりも低くすることができる。

If the diaphragm 1 and the support 3 are made of different materials, and the Young's modulus E of the material of the support 3 is low (that is, the rigidity G is low), the first resonance frequency f2 is hardly affected. The secondary resonance frequency f1 can be lowered to widen the frequency band. In the case where the frame 21, the diaphragm 1, and the support body 3 constituting the sandwiching portion 20 in the package 2 are formed by using a semiconductor process, the Young's modulus Em, E of the diaphragm 1 and the support body 3 as described above. For example, a polyimide layer is formed on one surface of a silicon wafer to remove silicon at a portion between the diaphragm 1 and the frame 21, and the diaphragm 1 and the frame 21 may be made different from each other. There is a method of removing polyimide other than the portion that is between and the portion that becomes the support 3. That is, the diaphragm 1 and the frame 21 of the package 2 are each composed of a silicon layer and a polyimide layer, and the support 3 is composed only of a polyimide layer. Can be made lower than the Young's modulus Em of the diaphragm 1.

  Furthermore, if the frequency band is widened by the above-mentioned various means, the anti-phase vibration is enhanced at the same time, so that the detection accuracy of the sound pressure spatial differential is improved (it is difficult to be buried in background noise).

Hereinafter, the displacement z _A to z _D measurement point A~D in the present embodiment will be described how to obtain a sound pressure space differential used in the spatio-temporal gradient method.

First, using the displacements z _A and z _B of the measurement points A and B of the diaphragm 1 with the longitudinal direction oriented in the x-axis direction, the sound pressure f (t) and the sound pressure time differential ft used in the spatiotemporal gradient method are used. A method for obtaining (t) and the sound pressure spatial differential fx (t) in the x-axis direction will be described.

As shown in FIG. 11A, the origin is set at the center of the diaphragm 1. Further, two points having the same distance from the origin on the x-axis are set as measurement points A and B, and a distance between the measurement points A and B is set to d (<L). Further, since the displacements z _A and z _B are minute, changes in the x coordinate of the measurement points A and B are ignored. Furthermore, as shown in FIG. 11 (b), when the incoming direction of the incoming sound (upward in FIG. 11 (b)) is the negative direction of the z axis, the coordinates of the measurement points A and B are (d / 2,0, z _A ), (−d / 2,0, z _B ). Further, the rotation angle of the diaphragm 1 around the y-axis and the position on the positive side of the x-axis with respect to the origin (the right side in FIGS. 11A and 11B) is displaced in the positive direction of the z-axis (see FIG. A rotation angle (hereinafter referred to as “displacement angle”) of the diaphragm 1 having a positive direction in the clockwise direction in FIG. The displacement angle φ can be approximated as φ = (z _A −z _B ) / d using the displacements z _A and z _B of the measurement points A and B.

It is assumed that the displacements z _A and z _B are minute and the change of the sound pressure due to the change of the z coordinate is not considered, and the force (sound pressure) that the diaphragm 1 receives from the incident sound at the coordinates (x, y) at time t is f ( x, y, t). Furthermore, the target point to be measured by the spatiotemporal gradient method is the origin, and f (t) = f (0,0, t), fx (t) = fx (0,0, t), fy (t) = fy (0,0, t) is approximated as f (x, y, t) = f (t) + fx (t) · x + fy (t) · y. Then, the resultant force F (t) in the positive z-axis direction (downward in FIG. 11B) acting on the diaphragm and the positive direction of the displacement angle φ with respect to the diaphragm 1 (clock in FIG. 11B). The moment N (t) acting in the rotation direction is expressed as follows.

また、逆相振動に関する運動方程式は、後述する参考文献１，２によると、変位角φと、上記のモーメントN(t)と、振動板の慣性モーメントＩと、支持体３のねじりばね定数ｋとを用いて、次式のようになる。

Further, according to References 1 and 2, which will be described later, the equation of motion related to the antiphase vibration is as follows: displacement angle φ, the moment N (t), the inertia moment I of the diaphragm, and the torsion spring constant k of the support 3. And the following equation is obtained.

すなわち、ｘ軸方向についての音圧空間微分fx(t)は、次式のように表される。

That is, the sound pressure space differential fx (t) in the x-axis direction is expressed as the following equation.

これと、変位角φを示す式φ＝(ｚ_Ａ−ｚ_Ｂ)／dとにより、ｘ軸方向についての音圧空間微分fx(t)が測定点Ａ，Ｂの変位ｚ_Ａ，ｚ_Ｂの２階時間微分を用いて表される。さらに、長手方向をｙ軸方向に向けた振動板１の測定点Ｃ，Ｄの変位ｚ_Ｃ，ｚ_Ｄの２階時間微分を用いて同様の計算を行えば、ｙ軸方向についての音圧空間微分fy(t)が得られる。

With this and the expression φ = (z _A −z _B ) / d indicating the displacement angle φ, the sound pressure space differential fx (t) in the x-axis direction is the displacement z _A , z _B of the measurement points A, B. Expressed using second order time differentiation. Further, if the same calculation is performed using second-order time differentiation of the displacements z _C and z _D of the measurement points C and D of the diaphragm 1 with the longitudinal direction in the y-axis direction, the sound pressure space in the y-axis direction A differential fy (t) is obtained.

Further, according to References 1 and 2, the equation of motion related to in-phase vibration is the spring constant K of each diaphragm 1 and the in-phase component of displacement z (t) = (z _A + z _B + z _C + z _D ) / 4 and the resultant force F (t) are expressed by the following equation.

すなわち、音圧f(t)=Kz(t)/WLを同相成分z(t)から得ることができる。なお、上記のばね定数Ｋは、振動板１の真上から加振を行った場合の変位と加振力より、フックの式を用いて求められる。

That is, the sound pressure f (t) = Kz (t) / WL can be obtained from the in-phase component z (t). The spring constant K is obtained by using the hook equation from the displacement and the excitation force when excitation is performed from directly above the diaphragm 1.

  Furthermore, the sound pressure time derivative ft (t) is obtained by time-differentiating the obtained sound pressure f (t).

  The sound pressure f (t), sound pressure time derivative ft (t) and sound pressure space derivative fx (t), fy (t) obtained as described above are the sound source localization and noise by the spatiotemporal gradient method. Can be used for removal. Since the technique of sound source localization and noise removal by the spatiotemporal gradient method is well known, description thereof is omitted.

  According to the above configuration, the sound pressure spatial differentials fx (t) and fy (t) in one direction can be detected for each diaphragm 1, so the sound pressure spatial differentials fx (t) and fy ( The size can be reduced as compared with the case where a plurality of diaphragms are used to detect t).

Further, the sound pressure attenuation width per unit distance is larger as it is closer to the sound source, so that the sound from the sound source closer to the diaphragm 1 has a reverse phase component (z _A −z _B ) obtained from this embodiment. / 2, (z _C −z _D ) / 2 is strongly reflected, and the reverse phase component (z _A −z _B ) / 2 and (z _C −z _D ) / 2 of this embodiment is It can be considered that the sound from a distant sound source is suppressed and the sound from a close sound source is emphasized.
<List of references>
Reference 1: Junji Ono, Akihito Saito, Shigeru Ando “Theory and Experiments of Localization Sensors for Miniaturized Sound Sources Simulating Drosophila (2nd Report)”, 19th Sensing Forum, pp.379-382,2002
Reference 2: N. Ono, A. Saito, and S. Ando, “Bio-mimicry Sound Source Localization with Gimbal Diaphragm”, IEEJ Transactions, Vol. 123-E, No.3, pp.92-97, 2003

It is a top view which shows the principal part of embodiment of this invention. It is a disassembled perspective view which shows the same as the above. It is explanatory drawing which shows the wraparound of the sound in the same as the above. (A) (b) is explanatory drawing which shows the example of arrangement | positioning of the piezoresistor in each same as the above. (A) (b) is explanatory drawing which respectively shows operation | movement same as the above, (a) shows a reverse phase vibration, (b) shows an in-phase vibration. It is explanatory drawing which shows the relationship between the frequency of incident sound and the maximum value (namely, amplitude) of the displacement of a measurement point in the same as the above. It is explanatory drawing which shows the definition of the parameter in the same as the above. (A)-(c) is a top view which shows the example of a respectively different change same as the above. It is explanatory drawing which shows the relationship between the width dimension of the support body in a connection part with a clamping part, a primary resonant frequency, and a secondary resonant frequency. It is explanatory drawing which shows the example of a change same as the above. (A) (b) is explanatory drawing which shows the definition of the parameter in each same as the above.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Diaphragm 2 Package 3 Support body 4a-4h Piezoresistor (The displacement detection means in Claim 1, 3 and the distortion detection means in Claim 2)
20 sandwiching part 21 frame (package in claim 3)
22 Cover

Claims (7)

At least one diaphragm having a flat rectangular parallelepiped shape, each made of an elastic material;
A package having a sandwiching portion for each diaphragm with a gap between the diaphragms from both sides in the short direction;
Each diaphragm is provided with two elastic materials, each having a flat shape with the thickness direction directed in the thickness direction of the diaphragm, and one end in the short direction at the center of the diaphragm in the longitudinal direction. A support body having one end connected to the other end and the other end connected to the sandwiched portion of the package;
A sound pressure spatial differential detection sensor comprising: displacement detection means for detecting displacement in the thickness direction at both longitudinal ends of each diaphragm. At least one diaphragm having a flat rectangular parallelepiped shape, each made of an elastic material;
A package having a sandwiching portion for each diaphragm with a gap between the diaphragms from both sides in the short direction;
Each diaphragm is provided with two elastic materials, each having a flat shape with the thickness direction directed in the thickness direction of the diaphragm, and one end in the short direction at the center of the diaphragm in the longitudinal direction. A support body having one end connected to the other end and the other end connected to the sandwiched portion of the package;
A sound pressure spatial differential detection sensor, wherein each support is provided with strain detection means for detecting strain caused by tension and torsion. At least one diaphragm having a flat rectangular parallelepiped shape, each made of an elastic material;
A package having a sandwiching portion for each diaphragm with a gap between the diaphragms from both sides in the short direction;
A cover of the package with a cavity in which each diaphragm is stored;
Each diaphragm is provided with two elastic materials, each having a flat shape with the thickness direction directed in the thickness direction of the diaphragm, and one end in the short direction at the center of the diaphragm in the longitudinal direction. A support body having one end connected to the other end and the other end connected to the sandwiched portion of the package;
A sound pressure spatial differential detection sensor comprising: displacement detection means for detecting displacement in the thickness direction at both longitudinal ends of each diaphragm.   The width dimension of the other end connected to the package is smaller than the width dimension of one end connected to the diaphragm in each support body, respectively. The sound pressure spatial differential detection sensor described in 1.   The sound pressure spatial differential detection sensor according to any one of claims 1 to 4, wherein a thickness dimension of each support is smaller than a thickness dimension of the diaphragms connected to each support body.   The sound pressure spatial differential detection sensor according to claim 1, wherein each of the supports is made of a material having a Young's modulus lower than that of each of the connected vibration parts.   The diaphragm, the support, and the sandwiching portion are provided in two sets, with the thickness direction of the diaphragm aligned and the longitudinal directions of the diaphragm orthogonal to each other. The sound pressure spatial differential detection sensor according to item 1.

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