JP2003163995A - Aerial ultrasonic microphone and ultrasonic detector equipped therewith - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aerial ultrasonic microphone where the directional characteristics of an ultrasonic pulse to be transmitted are made wide in a horizontal direction, and made narrow in a vertical direction. <P>SOLUTION: The aerial ultrasonic microphone 1 is used for an ultrasonic detector for detecting an object existing in a distance which is at most almost 10 m by using an ultrasonic wave. The microphone 1 is provided with an almost cylindrical piezoelectric element 2 using the broadening vibration mode or thickness vibration mode of a piezoelectric board, an acoustic matching layer 3 whose one main surface is bonded with the piezoelectric element 2, an annular vibrating case 4 for supporting the acoustic matching layer 3 wherein the piezoelectric element 2 is disposed inside, and lead wires 6a and 6b for connecting the both main surfaces of the piezoelectric element 2 to a terminal 7. In addition, the vibrating case 4 is constituted so as to be sealed with packing materials such as resin, and the acoustic matching layer 3 is formed by setting the thickness of both edges 3a and 3b so as to be thinner than that of a central part 3a. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aerial ultrasonic microphone mounted on a vehicle or the like and used for an ultrasonic detector for detecting surrounding objects using ultrasonic waves.

[0002]

2. Description of the Related Art Conventionally, as an aerial ultrasonic microphone of this type, for example, Japanese Patent No. 2651140 as shown in FIG.
There is an airborne ultrasonic microphone 100 disclosed as an issue.

In FIG. 14, (a), (b), (c)
Is a top view of the aerial ultrasonic microphone 100, an explanatory view of a side surface viewed from the direction AA of FIG. 3A, and FIG.
It is explanatory drawing of the side surface seen from the BB direction.

This airborne ultrasonic microphone 100 has several hundred
It is used for an ultrasonic detector for detecting an object existing at a distance of up to about 10 m by utilizing an ultrasonic wave having a frequency of kHz to several MHz, and one of the cylindrical piezoelectric elements 2 for performing oscillating vibration. An acoustic matching layer 3 for increasing the emissivity of the vibration of the piezoelectric element 2 into the air is adhered to the main surface of the piezoelectric element 2. A ring-shaped acoustic matching layer 3 surrounds the piezoelectric element 2 at the peripheral edge of the acoustic matching layer 3. The vibration case 4 is joined, both main surfaces of the piezoelectric element 2 and the terminals 7 are connected via lead wires 6a and 6b, and the vibration case 4 is sealed with a filling material such as resin.

Next, as shown in FIG. 15, a case will be described in which the aerial ultrasonic microphone 100 is used in an ultrasonic detector 101 mounted on the vehicle 8 and detecting an obstacle behind the vehicle 8.

In FIG. 15, (a) and (b) are a top view and a side view, respectively, showing the detection range of the rear portion of the vehicle 8 and the ultrasonic detector 101.

The ultrasonic detector 101 is mounted on a bumper 8a behind the vehicle 8 to detect an obstacle behind the vehicle 8, and includes a sensor section 110 formed by the aerial ultrasonic microphone 100. , A controller unit section 120 for controlling the transmission and reception of ultrasonic signals of the sensor section 110
And a display section 130 that receives a control signal transmitted from the controller unit section 120 and sounds a buzzer or blinks an LED.

When a control signal is intermittently sent from the controller unit section 120 to the sensor section 110, the sensor section 110 transmits an amplified ultrasonic pulse. When an obstacle exists within the detection range, this ultrasonic pulse hits the obstacle and a reflected wave is generated. When the sensor section 110 receives the reflected wave, a detection signal is sent to the controller unit section 120. Then, the controller unit section 120 sends a control signal to the display section 130,
The buzzer of the display unit 130 sounds and the LED blinks to detect an object.

FIG. 16 shows the ultrasonic detector 10 of the present inventor.
As an example, the directional characteristic of the ultrasonic pulse transmitted from the sensor unit 110 is measured when the experiment is performed using the vibration case 4 of the aerial ultrasonic microphone 100 formed of a plastic material having an outer diameter of about 60 mm. Is a graph that
The horizontal axis and the vertical axis indicate the relative values of the angle and pulse intensity of the ultrasonic pulse to be transmitted.

According to the measurement made by the present inventor, the directional characteristics of the ultrasonic pulse transmitted from the sensor section 110 were the characteristics shown in FIG. 16 in both the horizontal and vertical directions. That is, according to the above configuration, as shown in FIG. 15, the detection range of the ultrasonic detector 101 is such that the maximum detection width is substantially the same in both horizontal and vertical directions H101 and V10.
It is 1.

[0011]

When the aerial ultrasonic microphone as described above is mounted on a vehicle and used in an ultrasonic detector for detecting an obstacle behind the vehicle, the horizontal ultrasonic sensor is used at least in the vehicle width in the horizontal direction. It is desirable to have a relatively wide detection range in order to be able to detect obstacles within a corresponding width range, and it is relatively narrow in the vertical direction to prevent accidental detection of the road surface. It is desirable to configure it to have a detection range.

However, in the aerial ultrasonic microphone 100 used for the ultrasonic detector 101 having the above-mentioned configuration, as described above, the directivity characteristics of the ultrasonic pulse exhibit the same characteristic in both horizontal and vertical directions. , The maximum detection width is almost the same in both horizontal and vertical directions. Therefore, if the detection width in the horizontal direction is increased to detect an obstacle in the width range corresponding to the vehicle width, the detection width in the vertical direction is also increased, and the road surface is erroneously detected. However, if the vertical detection width is shortened to prevent false detection of the road surface, the horizontal detection width will also be shortened, and it will not be possible to detect obstacles in the width range equivalent to the vehicle width. There was concern that it would occur.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a directional characteristic of an ultrasonic pulse to be transmitted that has a wide characteristic in the horizontal direction and a narrow characteristic in the vertical direction. By providing an aerial ultrasonic microphone,
When an ultrasonic detector equipped with this aerial ultrasonic microphone is mounted on a vehicle and detects an obstacle behind the vehicle, it is possible to detect obstacles in a relatively wide detection range equivalent to the vehicle width without erroneously detecting the road surface. The purpose is to be able to detect objects.

[0014]

An aerial ultrasonic microphone according to a first aspect of the present invention includes at least a piezoelectric element that utilizes a spreading vibration mode or a thickness vibration mode of a piezoelectric substrate,
A piezoelectric element is provided with an acoustic matching layer having a predetermined thickness that is bonded to one surface, and a vibration case that supports the acoustic matching layer with the piezoelectric element inside, and transmits an ultrasonic pulse, In an aerial ultrasonic microphone that receives a reflected wave reflected from an object that has received the ultrasonic pulse and detects the object, the acoustic matching layer has a length in one direction of the acoustic matching layer in the other direction intersecting with the acoustic matching layer. It is characterized in that it is formed shorter than the length, and the surface of the vibration case that supports the acoustic matching layer is exposed at both ends in the one direction.

In the aerial ultrasonic microphone according to a second aspect of the present invention, in the configuration according to the first aspect, the acoustic matching layer is formed such that both end portions in the one direction are thinner than the central portion. is doing.

An aerial ultrasonic microphone according to a third aspect of the present invention has at least a piezoelectric element that utilizes a spreading vibration mode or a thickness vibration mode of a piezoelectric substrate and a predetermined thickness at which the piezoelectric element is bonded to one surface. Acoustic matching layer,
A vibrating case supporting the acoustic matching layer with the piezoelectric element inside, and transmitting an ultrasonic pulse and receiving a reflected wave reflected from an object that has received the ultrasonic pulse, In the aerial ultrasonic microphone for detecting the above, the acoustic matching layer is formed so that the thickness of both end portions in one direction is thinner than the thickness of the central portion.

According to a fourth aspect of the invention, there is provided the aerial ultrasonic microphone according to the first to third aspects, wherein the acoustic matching layer has both end portions in the one direction, and a step portion in a plan view in the other direction. And a step portion of a cross section along the one direction is formed in a substantially stepped shape.

According to a fifth aspect of the present invention, there is provided the aerial ultrasonic microphone according to the first to third aspects, wherein the acoustic matching layer has both end portions in one direction, and a step portion in a plan view in the other direction. It has a long substantially elliptical shape, and the step portion of the cross section along the one direction is formed so as to have a substantially step shape.

In the aerial ultrasonic microphone of the invention according to claim 6, in the structure according to claim 4 or 5, the stepped portion of the acoustic matching layer is tapered so that the thickness of the acoustic matching layer changes gently. It is provided.

According to a seventh aspect of the present invention, there is provided an aerial ultrasonic microphone according to the sixth aspect, wherein the taper is formed so that a cross section along the one direction has a substantially arc shape.

An ultrasonic detector according to an eighth aspect of the present invention is an ultrasonic detector including the aerial ultrasonic microphone according to any one of the first to seventh aspects, and ultrasonic signals transmitted and received by the sensor unit. And a display unit for receiving a control signal transmitted from the controller unit unit and executing a predetermined display.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION The aerial ultrasonic microphone of the present invention and an ultrasonic detector equipped with the same are designed so that the directional characteristics of an ultrasonic pulse to be transmitted are wide in the horizontal direction and narrow in the vertical direction. The purpose of doing is realized as follows.

The structure of an aerial ultrasonic microphone of the present invention and an ultrasonic detector equipped with the same will be described below with reference to the drawings. In the following description, the same reference numerals are given to the parts having basically the same basic functions as those described in the related art, such as the piezoelectric element 2 to the terminal 7.

FIG. 1 shows the first embodiment of the aerial ultrasonic microphone of the present invention.
It is a figure showing an embodiment of. In FIG.
(A), (b) and (c) are respectively a top view of the aerial ultrasonic microphone 1, an explanatory view of a side surface viewed from the AA direction in (a), and BB in (a). It is explanatory drawing of the side surface seen from the direction.

This aerial ultrasonic microphone 1 is used for an ultrasonic detector for detecting an object existing at a distance of up to about 10 m by using ultrasonic waves. A substantially cylindrical piezoelectric element 2 that utilizes a vibration mode, an acoustic matching layer 3 to which the piezoelectric element 2 is bonded to one main surface, and a ring-shaped piezoelectric element 2 that supports the acoustic matching layer 3 inside. Vibrating case 4,
The piezoelectric element 2 has lead wires 6a and 6b connecting between both main surfaces and the terminal 7, and the vibration case 4 is further sealed with a filling material such as resin.

In the aerial ultrasonic microphone 1 according to the first embodiment, the structure of the acoustic matching layer 3 is different from that described in the section of the prior art. That is, the acoustic matching layer 3
Is formed such that both end portions 3b, 3b in the direction along the line BB in FIG. 1A are thinner than the central portion 3a. More specifically, the acoustic matching layer 3 has both end portions 3b, 3b in a direction along BB, and the stepped portion has a substantially linear shape along AA as shown in FIG. The stepped portion is formed to have a substantially stepped cross section as shown in FIG. 3C, and further, between the central portion 3a and the both end portions 3b, 3b, the central portion 3a to the both end portions 3b, The taper 3c, 3c having a substantially arcuate cross section as shown in FIG. 3C is provided so that the thickness gradually changes toward 3b.

FIG. 2 shows a sensor section 20 of an ultrasonic detector 10 which will be described later, which is constructed by using the aerial ultrasonic microphone 1 described above.
FIG. 2A and 2B are respectively a top view of the sensor unit 20 and an explanatory view of a side surface viewed from the AA direction in FIG. 2A.

The sensor section 20 includes the above-mentioned aerial ultrasonic microphone 1, a holding rubber 21 for fixing the aerial ultrasonic microphone 1, and a housing for accommodating these and fixed to a bumper 8a behind the vehicle 8 which will be described later. 22, an electronic circuit section 23 that processes a control signal intermittently sent from a controller unit section 30 described later, and the electronic circuit section 2
3 and the controller unit 30. The signal line 24 and the connector 25 are connected to each other.

Next, as shown in FIG. 3, the sensor unit 20 constructed by using the aerial ultrasonic microphone 1 is mounted on the vehicle 8 to detect an obstacle behind the vehicle 8.
The case of being used as will be described.

In FIG. 3, (a) and (b) are a top view and a side view showing the detection range by the rear part of the vehicle 8 and the ultrasonic detector 10, respectively.

The ultrasonic detector 10 is mounted on a bumper 8a behind the vehicle 8 to detect an obstacle behind the vehicle 8, and includes a sensor unit 20 formed by the aerial ultrasonic microphone 1. A controller unit 30 for controlling the transmission and reception of ultrasonic signals of the sensor unit 20, and a display unit 40 for receiving a control signal transmitted from the controller unit unit 30 and sounding a buzzer or blinking an LED. Composed of.

When a control signal is intermittently sent from the controller unit section 30 to the sensor section 20, the sensor section 20
Emits an amplified ultrasonic pulse. When an obstacle exists within the detection range, the ultrasonic pulse hits the obstacle and generates a reflected wave. When the sensor section 20 receives the reflected wave, a detection signal is sent to the controller unit section 30. Then, the controller unit section 30 sends a control signal to the display section 40, the buzzer of the display section 40 sounds, and the LED blinks.

FIG. 4 shows a case where the present inventor conducted an experiment using the ultrasonic detector 10 made of a plastic material having an outer diameter of about 60 mm as the vibration case 4 of the aerial ultrasonic microphone 1. 5 is a graph in which the directional characteristics of ultrasonic pulses transmitted from the sensor unit 20 are measured. In the figure, (a) and (b) are graphs showing the directional characteristics in the horizontal and vertical directions, respectively, and the horizontal axis and the vertical axis represent the relative angles and pulse intensities of the ultrasonic pulses to be transmitted. Indicates the value.

According to the experiment conducted by the present inventor, the ultrasonic pulse emitted from the sensor unit 20 is emitted in a horizontal direction up to a relatively wide angle as shown in FIG. On the other hand, in the vertical direction, as shown in FIG. 7B, the signal is transmitted only to a relatively narrow angle. As a result, in the detection range of the ultrasonic detector 10, as shown in FIG. 3, the maximum detection width is widened to H10 in the horizontal direction as shown in FIG. 3A, which is substantially equal to the width of the vehicle 8. Objects existing within the range can be detected, and since the vertical direction is narrowed to V10 as shown in FIG. 7B, it is possible to prevent the road surface from being erroneously detected.

FIG. 5 shows the second embodiment of the airborne ultrasonic microphone of the present invention.
It is a figure showing an embodiment of. In FIG.
(A), (b) and (c) are respectively a top view of the aerial ultrasonic microphone 1, an explanatory view of a side surface viewed from the AA direction in (a), and BB in (a). It is explanatory drawing of the side surface seen from the direction.

This aerial ultrasonic microphone 1 has the above-mentioned first
The structure of the cross section of the acoustic matching layer 3 is different from that of the embodiment. That is, the acoustic matching layer 3 has both end portions 3b, 3b having a substantially linear shape in plan view of the step portion along the line AA as shown in FIG. 5A, and the step portions have the same cross section. It is formed so as to have a substantially stepped shape as shown in FIG. 3C so that both end portions 3b, 3b are thinner than the central portion 3a, and further, the central portion 3a and the both end portions 3b,
A taper 3c, 3c having a substantially linear cross section as shown in FIG. 3 (c) is formed between the central portion 3a and the both end portions 3b, 3b so as to be gradually thinned. It is provided.

FIG. 6 is a diagram showing a third embodiment of the aerial ultrasonic microphone of the present invention. In FIG.
(A), (b) and (c) are respectively a top view of the aerial ultrasonic microphone 1, an explanatory view of a side surface viewed from the AA direction in (a), and BB in (a). It is explanatory drawing of the side surface seen from the direction.

This aerial ultrasonic microphone 1 has the above-mentioned first structure.
The structure of the cross section of the acoustic matching layer 3 is different from that of the second embodiment. That is, the acoustic matching layer 3
Is a stepped portion 3c in which the plan view of the stepped portion is a substantially linear shape along AA as shown in FIG. 6A, and the cross section has a substantially stepped shape as shown in FIG. 6C. , 3c so that the thickness of both end portions 3b, 3b is smaller than the thickness of the central portion 3a.

FIG. 7 is a diagram showing a fourth embodiment of the aerial ultrasonic microphone of the present invention. In FIG.
(A), (b) and (c) are respectively a top view of the aerial ultrasonic microphone 1, an explanatory view of a side surface viewed from the AA direction in (a), and BB in (a). It is explanatory drawing of the side surface seen from the direction.

This aerial ultrasonic microphone 1 has the above-mentioned first structure.
The structure of the cross section of the acoustic matching layer 3 is different from that according to the third embodiment. That is, the acoustic matching layer 3
Is formed such that the plan view of the step portion is a substantially straight line shape along the line AA as shown in FIG. 6A, and the cross section has a substantially stepwise shape as shown in FIG. 6C. The thickness of both end portions 3b, 3b is made thinner than the thickness of the central portion 3a.

FIG. 8 is a diagram showing a fifth embodiment of the aerial ultrasonic microphone of the present invention. In FIG.
(A), (b) and (c) are respectively a top view of the aerial ultrasonic microphone 1, an explanatory view of a side surface viewed from the AA direction in (a), and BB in (a). It is explanatory drawing of the side surface seen from the direction.

This aerial ultrasonic microphone 1 is the above-mentioned first
The structure of the acoustic matching layer 3 is different from that according to the fourth embodiment. That is, the acoustic matching layer 3 has a substantially elliptical shape in which the plan view of the step portion is long in the direction along AA as shown in FIG. 6A, and the cross section in the direction along BB is the same ( It is formed so as to have a substantially stepped shape as shown in c) so that the thickness of both end portions 3b, 3b is thinner than the thickness of the central portion 3a.

FIG. 9 is a diagram showing a sixth embodiment of the aerial ultrasonic microphone of the present invention. In FIG.
(A), (b) and (c) are respectively a top view of the aerial ultrasonic microphone 1, an explanatory view of a side surface viewed from the AA direction in (a), and BB in (a). It is explanatory drawing of the side surface seen from the direction.

This aerial ultrasonic microphone 1 is the above-mentioned first microphone.
The structure of the acoustic matching layer 3 is different from that according to the fifth embodiment. That is, the acoustic matching layer 3 has a structure shown in FIG.
(A) The length in the direction along BB is shorter than the length in the direction along AA, and the main surface of the vibration case 4 supporting the acoustic matching layer is in the direction along BB. Both ends 4a,
It is formed so as to be exposed at 4a. Specifically, the acoustic matching layer 3 is formed in such a shape that both end portions in the direction along BB are cut in a substantially straight line in the direction along AA shown in FIG. A taper 3 having a substantially arc-shaped cross section as shown in FIG. 3C so that the thickness of both ends gradually decreases from 3a in the direction along BB.
c and 3c are provided.

FIG. 10 is a diagram showing a seventh embodiment of the aerial ultrasonic microphone of the present invention. 10, (a), (b), and (c) are respectively a top view of the aerial ultrasonic microphone 1, an explanatory view of a side surface viewed from the direction AA in FIG. 10 (a), and FIG. It is explanatory drawing of the side surface seen from the BB direction.

This aerial ultrasonic microphone 1 is the same as the above-mentioned sixth microphone.
The structure of the cross section of the acoustic matching layer 3 is different from that of the embodiment. That is, in the acoustic matching layer 3, the tapers 3c, 3c provided so that the thickness of both ends gradually decreases from the central portion 3a in the direction along the line BB have a substantially linear shape.

FIG. 11 is a diagram showing an eighth embodiment of the aerial ultrasonic microphone of the present invention. 11, (a), (b), and (c) are respectively a top view of the aerial ultrasonic microphone 1, an explanatory view of a side surface viewed from the direction AA of FIG. 11 (a), and FIG. It is explanatory drawing of the side surface seen from the BB direction.

This aerial ultrasonic microphone 1 includes the above-mentioned sixth microphone.
Also, the structure of the cross section of the acoustic matching layer 3 is different from that of the seventh embodiment. That is, the acoustic matching layer 3
Is a plan view of the step portion is AA as shown in FIG.
The end portions 3b, 3b are formed in a substantially straight line shape along the line and are formed so that their cross sections have a substantially stepwise shape as shown in FIG.
Is thinner than the thickness of the central portion 3a.

FIG. 12 is a diagram showing a ninth embodiment of the aerial ultrasonic microphone of the present invention. 12, (a), (b), and (c) are respectively a top view of the aerial ultrasonic microphone 1, an explanatory view of a side surface viewed from the direction AA in FIG. 12 (a), and FIG. It is explanatory drawing of the side surface seen from the BB direction.

This aerial ultrasonic microphone 1 includes the above-described sixth microphone.
The structure of the cross section of the acoustic matching layer 3 is different from that according to the eighth embodiment. That is, the acoustic matching layer 3 has a structure in which the above-described step portion is not provided.

FIG. 13 is a diagram showing a tenth embodiment of the aerial ultrasonic microphone of the present invention. In FIG. 13, (a), (b), and (c) are respectively a top view of the aerial ultrasonic microphone 1, an explanatory view of a side view taken along the line AA of FIG. 13 (a), and FIG. It is explanatory drawing of the side surface seen from the BB direction.

This aerial ultrasonic microphone 1 is the same as the above-mentioned sixth microphone.
The structure of the acoustic matching layer 3 is different from that according to the ninth embodiment. The acoustic matching layer 3 has a plan view shown in FIG.
It is formed so as to have a substantially elliptical shape that is long in the direction along AA as shown in (a).

According to the configuration of the aerial ultrasonic microphone 1 according to the second to tenth embodiments, an ultrasonic pulse exhibiting almost the same directional characteristics as that of the first embodiment described above is generated. I was able to send it. That is, the ultrasonic pulse could be emitted in a relatively wide angle in the horizontal direction, but could be emitted in a relatively narrow angle in the vertical direction. As a result, the ultrasonic detector provided with this aerial ultrasonic microphone 1 has a wide maximum detection width in the horizontal direction and can detect an object existing within a range substantially equal to the width of the vehicle 8, Also,
The maximum detection width in the vertical direction has become narrower, making it possible to prevent erroneous detection of road surfaces.

[0054]

In the aerial ultrasonic microphone of the invention according to any one of claims 1 to 7, it is possible to emit an ultrasonic pulse exhibiting a directivity characteristic that is relatively wide in the horizontal direction and relatively narrow in the vertical direction. it can.

An ultrasonic detector according to an eighth aspect of the present invention includes the aerial ultrasonic microphone according to any one of the first to seventh aspects. As a result, it is possible to detect an object in a relatively wide range in the horizontal direction, but only an object in a relatively narrow range in the vertical direction, so that it is possible to prevent erroneous detection of a road surface or the like. it can.

[Brief description of drawings]

FIG. 1 is a diagram showing a first embodiment of an aerial ultrasonic microphone of the present invention.

FIG. 2 is a diagram showing a sensor unit of an ultrasonic detector configured using the aerial ultrasonic microphone of the present invention.

FIG. 3 is an explanatory diagram showing a case where the ultrasonic detector including the aerial ultrasonic microphone of the present invention is mounted on a vehicle and used.

FIG. 4 is a diagram showing directional characteristics of ultrasonic pulses transmitted from the aerial ultrasonic microphone of the present invention.

FIG. 5 is a diagram showing a second embodiment of an aerial ultrasonic microphone of the present invention.

FIG. 6 is a diagram showing a third embodiment of an aerial ultrasonic microphone of the present invention.

FIG. 7 is a diagram showing a fourth embodiment of an aerial ultrasonic microphone of the present invention.

FIG. 8 is a diagram showing a fifth embodiment of an aerial ultrasonic microphone of the present invention.

FIG. 9 is a diagram showing a sixth embodiment of the aerial ultrasonic microphone of the present invention.

FIG. 10 is a diagram showing a seventh embodiment of an aerial ultrasonic microphone of the present invention.

FIG. 11 is a diagram showing an eighth embodiment of the aerial ultrasonic microphone of the present invention.

FIG. 12 is a diagram showing a ninth embodiment of the aerial ultrasonic microphone of the present invention.

FIG. 13 is a diagram showing a tenth embodiment of an aerial ultrasonic microphone of the present invention.

FIG. 14 is a diagram showing a conventional airborne ultrasonic microphone.

FIG. 15 is an explanatory diagram showing a case where an ultrasonic detector including an airborne ultrasonic microphone of a conventional example is mounted on a vehicle and used.

FIG. 16 is a diagram showing a directional characteristic of an ultrasonic pulse transmitted from a conventional airborne ultrasonic microphone.

[Explanation of symbols]

1 Aerial ultrasonic microphone 2 Piezoelectric element 3 Acoustic matching layer 4 vibration cases 10 Ultrasonic detector 20 sensor 30 Controller unit section 40 Display

Claims (8)

[Claims] 1. A piezoelectric element utilizing at least a spreading vibration mode or a thickness vibration mode of a piezoelectric substrate, an acoustic matching layer having a predetermined thickness to which the piezoelectric element is bonded to one surface, and the piezoelectric element inside. And a vibration case that supports the acoustic matching layer, which transmits an ultrasonic pulse and receives a reflected wave reflected from an object that has received the ultrasonic pulse to detect the object. In the acoustic wave microphone, the acoustic matching layer is formed such that its length in one direction is shorter than the length in the other direction intersecting with the acoustic matching layer, and the surface supporting the acoustic matching layer of the vibrating case has both ends in the one direction. An airborne ultrasonic microphone characterized by being exposed at. 2. The aerial ultrasonic microphone according to claim 1, wherein the acoustic matching layer is formed such that the thickness of both ends in the one direction is smaller than the thickness of the central part. 3. A piezoelectric element utilizing at least a spreading vibration mode or a thickness vibration mode of a piezoelectric substrate, an acoustic matching layer having a predetermined thickness to which the piezoelectric element is adhered to one surface, and the piezoelectric element inside. And a vibration case that supports the acoustic matching layer, which transmits an ultrasonic pulse and receives a reflected wave reflected from an object that has received the ultrasonic pulse to detect the object. An acoustic ultrasonic microphone, wherein the acoustic matching layer is formed such that the thickness of both ends in one direction is smaller than the thickness of the central portion. 4. The acoustic matching layer has, at both ends in the one direction, a step portion having a substantially linear shape in a plan view along the other direction, and a step portion of a cross section along the one direction is substantially formed. The aerial ultrasonic microphone according to claim 1, wherein the aerial ultrasonic microphone is formed to have a step shape. 5. The acoustic matching layer has a substantially elliptical shape in plan view of the step portion at both ends in the one direction, and the step portion of a cross section along the one direction has a substantially staircase. The aerial ultrasonic microphone according to claim 1, which is formed to have a shape. 6. The airborne ultrasonic microphone according to claim 4, wherein the stepped portion of the acoustic matching layer is provided with a taper such that the thickness of the acoustic matching layer changes gently. 7. The aerial ultrasonic microphone according to claim 6, wherein the taper is formed so that a cross section along the one direction has a substantially arc shape. 8. A sensor unit including the aerial ultrasonic microphone according to claim 1, a controller unit unit for controlling ultrasonic signals transmitted and received by the sensor unit, and a controller unit unit. An ultrasonic detector comprising: a display unit that receives a control signal transmitted from the display unit and executes a predetermined display.