KR20150134912A - Multi-mode type piezoelectric hydrophone - Google Patents

Abstract

The present invention relates to a multi-mode type piezoelectric vector hydrophone which can make a cardioid beam pattern using sound waves received by using a plurality of piezoelectric bodies, and detect both the size and the direction of a sound signal by obtaining four signals with different phases. The multi-mode type piezoelectric vector hydrophone according to the present invention comprises: a cylindrical housing (11); and a plurality of piezoelectric bodies (12) whose cross sections are formed in an arc shape along the inner surface of the housing (11), wherein electrodes are individually formed on the inside and the outside of the arc, and which are arranged along the inner surface of the housing (11).

Description

[0001] MULTI-MODE TYPE PIEZOELECTRIC HYDROPHONE [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a hydrophone for measuring sound waves in water, and more particularly, to a hydrophone using a plurality of piezoelectric bodies to generate a heartbeam beam pattern using received sound waves, The present invention relates to a multimode piezoelectric vector hydrophone capable of detecting all directions of a multimode piezoelectric vector hydrophone.

A water hammer that detects a sound source is equipped with a receiver or a submarine.

Since it is difficult to transmit radio waves in water, various types of information are acquired using sound waves. By using the hydrophone, various kinds of information are acquired by receiving a sound wave after being emitted from a ship or a submarine, and receiving a sound wave emitted from a sound source located in the water.

Typically, the hydrophone uses a cylindrical piezoelectric body to measure the size of a sound wave.

The cylindrical piezoelectric member is usually manufactured by sintering a ceramic powder to form a shape. An electrode is coated on the formed ceramic and polarized to manufacture a cylindrical piezoelectric member.

The hydrophone according to the related art manufactured using such a cylindrical piezoelectric body allows the center of the cylindrical piezoelectric body to be located at the acoustic center inside.

However, the conventional hydrophone has the problem that it is difficult to estimate the position of the sound source, only the size of the sound signal can be measured for only one acoustic signal.

Therefore, it is inconvenient to install the plurality of hydrophones or change the position of the hydrophone in order to know the direction of the sound source.

The following prior art document relates to a 'underwater acoustic sensor', in which a load due to its own weight is applied to a front weight and an acoustic window during operation, transportation, storage and installation of an underwater acoustic sensor, Discloses a technique related to an underwater acoustic sensor that improves the durability and accuracy by minimizing the length and weight of the entire acoustic sensor.

KR 10-0946753 B1

SUMMARY OF THE INVENTION The present invention has been developed in order to solve the above-mentioned problems, and it is an object of the present invention to provide a piezoelectric vibrator having an arcuate piezoelectric element arranged circularly, artificially forming a heartbeam beam pattern from a received sound wave, The present invention provides a multimode piezoelectric vector hydrophone capable of detecting both the size and the direction of a piezoelectric vibrator.

According to an aspect of the present invention, there is provided a multimode piezoelectric vector hydrophone including a housing formed in a cylindrical shape, an arc shape having a cross section along an inner side surface of the housing, An electrode is formed, and a plurality of piezoelectric bodies are arranged along the inner surface of the housing.

The piezoelectric bodies are provided in four pieces having the same arc length, and the housing is arranged on the inner side.

And an upper end cap and a lower end cap for fixing the piezoelectric body to the housing are installed on the upper and lower portions of the piezoelectric body, respectively.

The piezoelectric body is formed of a powder ceramic or a single crystal.

The housing is made of epoxy.

An omni beam pattern is obtained by summing the voltage values output from the four piezoelectric bodies, and a dipole beam pattern is obtained by subtracting the sum of any two voltage values out of the four piezoelectric bodies and the sum of the remaining two voltage values And calculating a heartbeam beam pattern from the sum of the omni beam pattern and the dipole beam pattern to estimate a sound source position of a sound wave.

And the incident angle of the sound wave is estimated by substituting the phase difference of the sound wave incident at the acoustic center of the four piezoelectric bodies into the following equation.

(Where r is the radius of a circle with respect to the center of the piezoelectric body arranged in four pieces,? T: difference in arrival time of sound waves in each divided piezoelectric body, c: sound velocity in water)

According to the multimode piezoelectric vector hydrophone according to the present invention having the above-described structure, a heartbeam beam pattern is formed on a sound wave received from a piezoelectric body divided in equal sizes, or four signals having different phases So that it is possible to detect both the size and the direction of the acoustic signal.

1 is a perspective view showing a multimode piezoelectric vector hydrophone according to the present invention.
2 is a cross-sectional view of a multimode piezoelectric vector hydrophone according to the present invention.
3 is a cross-sectional view taken along line AA of Fig.
4 to 6 show a beam pattern represented by the sum of voltage values output from the piezoelectric bodies in a multimode piezoelectric vector hydrophone according to the present invention. Fig. 4 shows an Omni beam pattern, Fig. 5 A dipole beam pattern, and Fig. 6 shows a heartbeam beam pattern.

Hereinafter, a multimode piezoelectric vector hydrophone according to the present invention will be described in detail with reference to the accompanying drawings.

A multimode piezoelectric vector hydrophone according to the present invention comprises a housing 11 formed in a cylindrical shape and an arc shape having a cross section along an inner surface of the housing 11, And four piezoelectric bodies 12 arranged along the inner surface of the housing 11.

The housing (11) forms the outer shape of the hydrophone (1). The housing 11 is formed in a hollow shape, and a plurality of piezoelectric bodies 12, an upper end cap 13, and a lower end cap 14, which will be described below, are installed in the housing 11.

The housing 11 is preferably made of epoxy to efficiently transmit sound waves from the outside to the inside of the housing 11.

Further, it is preferable that the housing 11 is located at the outermost position, and is molded by arranging other components.

The piezoelectric body (12) is installed inside the housing (11). Each of the piezoelectric bodies 12 is formed to have an arcuate shape, and a plurality of the piezoelectric bodies 12 are disposed along the inner circumference of the housing 11. [ That is, the piezoelectric body 12 is formed by dividing the single-piece piezoelectric body made of powder ceramic or single crystal into a cylindrical shape at four equal angular intervals to form respective piezoelectric bodies 12, .

Since the piezoelectric bodies 12 are each formed in an arc-like shape, the piezoelectric bodies 12 have different acoustic center points.

Electrodes are formed inside and outside the piezoelectric body 12, that is, inside and outside in the radial direction of the housing 11, so that the conductor 17 can be connected to the piezoelectric body 12. Ultimately, the piezoelectric body 12 can be electrically connected to another external electrode 16 through the conductor 17 or can be grounded to measure the voltage output from the piezoelectric body 12.

The lead wire is electrically connected to the outside by being connected to the conductive pin 15 formed at one side of the housing 11. [

Since the piezoelectric body 12 has a quadrupole shape, a signal output from the piezoelectric bodies 12 can be formed into a heartbeat beam pattern or a phase of a sound wave can be made different, thereby obtaining direction information of a sound wave .

The piezoelectric body 12 preferably has a thickness of 1 mm and a height of 15 mm.

The upper end cap 13 and the lower end cap 14 fix the piezoelectric bodies 12 installed on the inner surface of the housing 11 so as not to move up and down.

That is, the upper end cap 13 is located on the upper portion of the piezoelectric body 12 and the lower end cap 14 is located on the lower portion of the piezoelectric body 12 so that the piezoelectric body 12, So as not to move up and down. The piezoelectric bodies 12 can be maintained in a predetermined position within the housing 11 by the upper end cap 13 and the lower end cap 14 made of synthetic resin or the like.

In particular, any one of the upper end cap 13 and the lower end cap 14 is provided with a lead 17 electrically connected to an electrode formed on each of the piezoelectric bodies 12 to be electrically connected to the outside of the housing 11 A conductive pin 15 may be provided. FIG. 2 shows a configuration in which the conductive pin 15 is formed only on the upper end cap 13.

Reference numeral 19 denotes a molding supporting pin for supporting the housing 11 and the lower end cap 14 during the process of manufacturing the multimode piezoelectric vector hydrophone 1 according to the present invention by molding.

The operation of the multimode piezoelectric vector hydrophone according to the present invention having the above-described structure will now be described.

In the multimode piezoelectric hydrophone 1 according to the present invention, four piezoelectric bodies 12 are formed in the same manner. If the voltage values output from the respective piezoelectric bodies are V1, V2, V3, and V4, The beam pattern, the dipole beam pattern, and the heartbeam pattern can be expressed by the following equations (1) to (3).

&Quot; (1) "

Omni = V1 + V2 + V3 + V4

&Quot; (2) "

Dipole = (V1 + V2) - (V3 + V4)

&Quot; (3) "

Heart Beam Pattern = Omni + Dipole

That is, an omni-beam pattern is obtained by summing the voltage values output from the four piezoelectric bodies 12, and the sum of two voltage values among the voltage values output from the four piezoelectric bodies 12 and the remaining two voltage values And the heartbeam beam pattern can be obtained from the sum of the omni beam pattern and the dipole beam pattern.

The beam patterns are shown in FIGS. 4 to 6, respectively. FIG. 4 shows an omni beam pattern, FIG. 5 shows a dipole beam pattern, and FIG. 6 shows a heartbeam beam pattern.

It is possible to separate the left and right sound sources from the sound waves received through the heartbeam pattern and estimate the position of the sound source.

Since the four piezoelectric bodies 12 are arranged in the housing 11, the azimuth of the sound source can be estimated by calculating the phase difference of the sound waves incident on the acoustic center points of the respective piezoelectric bodies 12.

That is, when the radius of a circle with respect to the center of the piezoelectric body 12 arranged in four is r, the difference between the arrival time of the sound wave to each divided piezoelectric body is? T, and the sound velocity in water is c, Can be expressed by the following equation (4).

&Quot; (4) "

From Equation (4), the incident angle of the sound wave can be obtained, so that the direction of the sound source can be measured.

As described above, in the multimode piezoelectric vector hydrophone according to the present invention, the four piezoelectric bodies having the same shape as the cylindrical divided body are arranged and the heartbeam pattern sensitivity is measured using the voltage value outputted from each piezoelectric body And the direction of the sound source can be estimated by calculating the phase difference of the sound wave in each of the piezoelectric bodies.

1: hydrophone 11: housing
12: piezoelectric body 13: upper end cap
14: lower end cap 15: conductive pin
16: external electrode 17: conductor
18: external wire 19: mold support pin

Claims (7)

A housing formed into a cylindrical shape,
A plurality of piezoelectric bodies each having an end face formed in an arc shape along an inner side surface of the housing, electrodes formed on the inside and the outside of the circular arc, and a plurality of piezoelectric bodies arranged along the inner side face of the housing.
The method according to claim 1,
Wherein the piezoelectric bodies are provided in four having the same arc length, and the housing is arranged on the inner side.
The method according to claim 1,
And an upper end cap and a lower end cap for fixing the piezoelectric body to the housing are installed on upper and lower portions of the piezoelectric body, respectively.
The method according to claim 1,
Wherein the piezoelectric body is formed of a powder ceramic or a single crystal.
The method according to claim 1,
Wherein the housing is made of epoxy. ≪ RTI ID = 0.0 > 11. < / RTI >
3. The method of claim 2,
An omni beam pattern is obtained by summing the voltage values output from the four piezoelectric bodies, and a dipole beam pattern is obtained by subtracting the sum of any two voltage values out of the four piezoelectric bodies and the sum of the remaining two voltage values Wherein the heartbeam pattern is obtained by summing the omni beam pattern and the dipole beam pattern, and estimating the sound source position of the sound wave.
3. The method of claim 2,
Wherein a phase difference of a sound wave incident at an acoustic center point of the four piezoelectric bodies is substituted into the following expression to estimate the incident angle of the sound wave.

(Where r is the radius of a circle with respect to the center of the piezoelectric body arranged in four pieces,? T: difference in arrival time of sound waves in each divided piezoelectric body, c: sound velocity in water)

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