JP2569748B2 - Electroacoustic transducer - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an electro-acoustic transducer, and more particularly to an electro-acoustic transducer applied to an underwater target detection system that measures the incident direction of an incoming sound wave in water.

[Conventional technology]

A plurality of transducers each having two divided electrodes provided on the inner peripheral surface and the outer peripheral surface of the cylindrical piezoelectric body are stacked on the central axis of the cylindrical piezoelectric body, and the output of each electrode of these vibrators is supplied to two transformers. An electroacoustic transducer of an underwater target detection system that knows the incident direction of a sound wave arriving in water is well known.

FIG. 4 is a configuration diagram showing an example of a conventional electroacoustic transducer, and includes vibrators 11a and 11b, a first transformer 9a, and a second transformer 9b which are stacked and arranged in the same state. .

The vibrator 11a is provided on the cylindrical piezoelectric body 6a, inner electrodes 7a and 7b provided on the inner circumferential surface of the cylindrical piezoelectric body 6a and divided so as to face each other with a small interval, and provided on the outer circumferential surface of the cylindrical piezoelectric body 6a. It has external electrodes 8a and 8b divided so as to face each other with a small interval. Also, the dividing direction of the inner electrodes 7a, 7b and the dividing direction of the outer electrodes 8a, 8b are orthogonal to each other,
Further, a polarization process is performed in the illustrated direction 10a (from the inner peripheral surface to the outer peripheral surface).

The vibrator 11b has the same configuration as the vibrator 11a, and inner electrodes 7c and 7d are provided on the inner peripheral surface of the cylindrical piezoelectric body 6b, and outer electrodes 8c and 8d are provided on the outer peripheral surface of the cylindrical piezoelectric body 6b. ing. The direction of division of the inner electrodes 7c, 7d is orthogonal to the direction of division of the outer electrodes 8c, 8d, and the same polarization processing as that of the vibrator 11a is performed.

Now, considering a rectangular coordinate system consisting of X, Y, and Z axes, when the Z axis is made coincident with the central axes of the transducers 11a and 11b, on the X and Y planes, the minute interval portion of the external electrode and the central axis Is the line connecting
When the X axis is a line connecting the minute interval portion of the inner surface electrode and the central axis, and the X axis is the incident direction of the sound wave arriving toward the central axis, the incident direction θ of the incoming sound wave can be defined. .

Each of the transformers 9a and 9b has a primary winding with a center tap. Here, for the primary winding of the transformer 9a,
By supplying the outputs of the outer electrodes 8a, 8b and 8c, 8d of the vibrators 11a and 11b in parallel, respectively, the secondary winding has a figure-shaped dipole proportional to the cosine (cos θ) of the incident azimuth θ of the incoming sound wave. signal V _X is generated. Also, by supplying the outputs of the inner electrodes 7a, 7b and 7c, 7d of the transducers 11a and 11b in parallel to the primary winding of the transformer 9b,
The secondary winding dipole signal V _Y of figure eight proportional to the sine (sin [theta) of the incident orientation θ of the incoming sound wave is generated. Further, an omni-directional omni signal V _OMN is generated at the center tap of the primary winding of the transformers 9a and 9b.

The above-described dipole signals V _X and V _Y are output signals obtained by assuming the outer surface electrode and the inner surface electrode as acoustic dipoles, and differentially inputting the outputs of these electrodes to a transformer. Since the dividing directions of the inner surface electrodes are different from each other by 90 degrees, they have characteristics that are orthogonal to each other. Therefore, the incident direction θ of the incoming sound wave can be obtained from the dipole signals V _X and V _Y. Also, the omni signal V
The quadrant of the incident azimuth θ can be determined by _OMN .

[Problems to be solved by the invention]

In the above-described conventional electroacoustic transducer, the primary longitudinal vibration along the circumference of the vibrator, that is, the signal of the longitudinal vibration having two nodes on the circumference, and the zero-order longitudinal vibration, that is, the circumference A dipole signal and an omni signal are obtained by separating and extracting a signal as a so-called respiratory oscillation having no node above.

However, the frequency of the sound wave to be measured becomes wide, and an integral transverse wave stands in the circumferential direction of the vibrator.
At a frequency at which flexural resonance occurs, a signal due to flexural resonance is added to the dipole signal, disturbing the directivity of the dipole, and as a result, the azimuth accuracy is significantly deteriorated.

In addition, since the polarization directions of the two vibrators are the same, there is a disadvantage that phase inversion occurs due to the difference in electrodes, and phase compensation for this is required.

An object of the present invention is to eliminate the above-mentioned drawbacks and to compensate for disturbance of dipole directivity due to flexural resonance occurring in the circumferential direction of the vibrator when the frequency to be measured is widened, and to reduce phase due to the difference in electrodes. An object of the present invention is to provide an electroacoustic transducer that can eliminate inversion compensation.

[Means for solving the problem]

In the electroacoustic transducer of the present invention, the inner peripheral surface of the cylindrical piezoelectric body is provided with an inner surface electrode that is divided into two equal parts so as to face each other, and the outer peripheral surface of the cylindrical piezoelectric body has a dividing direction of the inner surface electrode. An outer surface electrode divided into two equal parts is provided so as to be orthogonal to and opposed to the first vibrator. The first vibrator has a cylindrical piezoelectric body polarized in a predetermined direction. Similarly, an inner surface electrode and an outer surface electrode are formed, and
The second piezoelectric element is polarized in a direction opposite to that applied to the cylindrical piezoelectric body of the first vibrator, and the second vibrator is stacked and disposed on the central axis of the first vibrator so as to be shifted from each other by 90 degrees. It has a vibrator and two primary windings each provided with a center tap. One primary winding is connected to the output of each of the divided outer electrodes of the first vibrator, and the other primary winding is connected to the primary winding. The output of each of the divided inner electrodes of the second vibrator is connected to the winding, and the output of the outer electrode of the first vibrator and the output of the inner electrode of the second vibrator are differentially connected. It has a first transformer in which a combined output is generated in a secondary winding, and two primary windings each provided with a center tap. One of the primary windings is divided from the first vibrator. The output of each inner electrode is connected to the other primary winding, and the other primary winding is connected to each of the divided outer electrodes of the second vibrator. A second transformer to which a force is connected and a differential combined output of the output of the inner electrode of the first oscillator and the output of the outer electrode of the second oscillator is generated in the secondary winding. The omni-directional omni signal is generated between the center taps of the first and second transformers. The first and second vibrators may be formed of the same cylindrical piezoelectric body.

In the electro-acoustic transducer of the present invention, the inner peripheral surface of the cylindrical piezoelectric body is provided with an inner surface electrode divided into two so as to face each other, and the inner peripheral surface of the cylindrical piezoelectric body is divided into two parts. An outer surface electrode divided into two equal parts so as to be opposed to each other in a direction perpendicular to the direction, a first vibrator having a cylindrical piezoelectric body polarized in a predetermined direction, and the first vibrator; The inner electrode and the outer electrode are formed in the same manner as described above, and a polarization process is performed in a direction opposite to that applied to the cylindrical piezoelectric body of the first vibrator. A second vibrator stacked on the shaft with a 90 ° offset from each other and a primary winding with a center tap are provided. One terminal of the primary winding is divided into the first vibrator and the first vibrator. One output of the external electrode is connected to the other terminal of the primary winding, and the second terminal is connected to the other terminal of the primary winding. One output of the divided inner electrode is connected, and the other output of the outer electrode of the first vibrator and the other output of the second inner electrode are connected to the center tap, respectively. A first transformer in which a differential combined output of an output of an inner electrode of the first oscillator and an output of an outer electrode of the second oscillator is generated in a secondary winding, and a primary winding with a center tap. One terminal of the primary winding is connected to one output of the divided inner electrode of the first vibrator, and the other terminal of the primary winding is connected to the other terminal of the second vibrator. One output of the divided outer electrode is connected, and the other output of the inner electrode of the first vibrator and the other output of the outer electrode of the second vibrator are connected to the center tap. , The first
A second transformer in which a differential combined output of an output of an inner electrode of the oscillator and an output of an outer electrode of the second oscillator is generated in a secondary winding. The omni-directional omni signal is generated between the center taps. The first and second vibrators may be formed of the same cylindrical piezoelectric body.

〔Example〕

 Next, the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing a first embodiment of the present invention.
A first vibrator 5a and a second vibrator 5b configured in the same manner as the conventional example shown in FIG. 4 are stacked on the same central axis.

The first vibrator 5a includes a cylindrical piezoelectric body 1a and this cylindrical piezoelectric body 1a.
Inner electrodes 2a, 2b provided on the inner peripheral surface of 1a and divided into two equal parts so as to face each other at a small interval, and outer surfaces provided on the outer peripheral surface of the cylindrical piezoelectric body 1a so as to face each other at a small interval It has electrodes 3a and 3b. The division direction of the inner electrodes 2a, 2b and the division direction of the outer electrodes 3a, 3b are orthogonal to each other. In addition, polarization processing is performed in the illustrated direction 10a (from the inner peripheral surface to the outer peripheral surface).

The second vibrator 5b has the same configuration as the first vibrator 5a. That is, the cylindrical piezoelectric body 1b and the cylindrical piezoelectric body 1b
The inner electrodes 2c and 2d provided on the inner peripheral surface of the cylindrical piezoelectric body 1b and divided so as to face each other at a minute interval, and the outer electrodes provided on the outer peripheral surface of the cylindrical piezoelectric body 1b and divided into two equal parts so as to face each other at a minute interval 3c, 3d, and the dividing direction of the inner electrodes 2c, 2d and the dividing direction of the outer electrodes 3c, 3d are orthogonal to each other. The direction 1 is opposite to the polarization direction 10a of the first vibrator 5a.
0b (from the outer peripheral surface to the inner peripheral surface) is subjected to polarization processing.

By the way, when laminating the first and second vibrators 5a and 5b, the first and second vibrators 5a and 5b are laminated so that they are shifted from each other by 90 degrees about the center axis, that is, the dividing directions of the outer electrodes of the two vibrators are orthogonal to each other. . Here, on the X, Y plane when the Z axis is made coincident with the central axes of the transducers 5a and 5b, a line connecting the minute interval portion of the outer surface electrode of the first transducer 5a and the central axis is represented by Y.
Assuming that the axis is the axis and the line connecting the minutely spaced portion of the inner surface electrode and the central axis is the X axis, the angle between the incident direction of the sound wave arriving toward the central axis and the X axis is the incident direction θ of the incoming sound wave.

First transformer 4a ₁ and the second transformer 4b ₁ has two primary windings dated center tap respectively.
Then, the first one of the primary winding of the transformer 4a _1, the outer surface electrode 3a of the first oscillator 5a, the output of the 3b type differential to the other of the primary winding, the second oscillator The outputs of the inner electrodes 2c and 2d of 5b are differentially input. Similarly, the second one of the primary winding of the transformer 4b _1, the inner surface electrode 2a of the first oscillator 5a, the output of 2b to input differential, and the other of the primary winding, the second vibration Child
The outputs of the outer electrodes 3c and 3d of 5b are differentially input.

Thus, the inner surface electrode of the outer surface electrode and the second oscillator 5b of the first oscillator 5a respectively differentially connected to a first of the two primary windings of the transformer 4a _1, also the first vibration The inner electrode of the transducer 5a and the outer electrode of the second transducer 5b are connected to the second transformer 4b.
_By differentially connecting to the two primary windings of 1, respectively, without compensating for phase inversion due to electrode differences,
The first secondary winding of the transformer 4a _1, output dipole signal V _X in the X direction component proportional to incoming waves cosine of the incident azimuth θ of (cos [theta]) is also of the second transformer 4b ₁ two the following winding, dipole V _Y of the Y-direction component proportional to the sine (sin [theta) of the incident azimuth θ of arrival wave is outputted.

Further, the connection of the primary windings of the first and second transformers 4a ₁ and 4b ₁ viewed from the center tap has an effect of short-circuiting the electrodes connected to the primary windings of the respective transformers.
Between the center tap of the primary winding to which the inner electrode is connected and the center tap of the primary winding to which the outer electrode is connected,
An omnidirectional omni signal V _OMN is obtained.

FIG. 5 is a diagram showing the directional characteristics of a dipole signal when flexural resonance occurs. Here, FIG.
7 shows a dipole signal component by the inner electrode and the outer electrode of the vibrator 5a, and FIG. 6B shows a dipole signal component by the inner electrode and the outer electrode of the second vibrator 5b. At the frequency where the flexural resonance occurs, the directional characteristic is distorted as shown in the figure because the flexural resonance signal is added to the dipole signal. The dipole signal having the distorted directional characteristic is synthesized by the two primary windings of the transformers 4a ₁ and 4b ₁ , and the distortion components are averaged and suppressed, thereby obtaining a normal signal as shown in FIG. Dipole signals V _X and V _Y having directivity characteristics are obtained.

In the embodiment described above, the first oscillator and the second oscillator
In the above, the case where one oscillator is used is described. However, a plurality of first oscillators and the same number of second oscillators are stacked, and a plurality of first and second oscillators are formed. By using them in parallel, it is possible to improve the receiving sensitivity of the sound wave.

 FIG. 2 is a view showing a second embodiment of the present invention.

Here, the function of the two vibrators stacked in the first embodiment is realized by using the same cylindrical piezoelectric body 1c.

In FIG. 2, the electrodes provided on the inner and outer peripheral surfaces of one cylindrical piezoelectric body 1c respectively have two electrodes above and below the central axis.
It is divided into equal parts. On the upper part of the cylindrical piezoelectric body 1c,
As in the case of the transducer 5a shown in FIG. 1, inner electrodes 2e and 2f and outer electrodes 3e and 3f which are divided so as to face each other with a small interval are formed. In the lower part of the cylindrical piezoelectric body 1c, inner electrodes 2g and 2h and outer electrodes 3g and 3h, which are divided so as to face each other with a small interval, like the vibrator 5b shown in FIG. Is formed. Note that the minutely spaced portion of the inner surface electrode and the minutely spaced portion of the outer surface electrode are shifted by 90 degrees with respect to the central axis.

Further, the inner and outer surface electrodes of the upper portion and the inner and outer surface electrodes of the lower portion are positioned such that the minute interval portions are shifted from each other by 90 degrees about the center axis, and the upper and lower portions are Polarization is performed in the reverse direction. In this manner, the third vibrator 5c having the characteristics of the first vibrator 5a and the second vibrator 5b shown in FIG. 1 can be configured.

Note that the transformer and the connection with the transformer are the same as in the first embodiment, and a description thereof will be omitted. In addition, an even number of such third vibrators are stacked and arranged, so that the receiving sensitivity of a sound wave can be improved.

 FIG. 3 is a block diagram showing a third embodiment of the present invention.

Here, the first and second vibrators 5a and 5b are the same as those in the first embodiment shown in FIG. First and second
Transformers 4a ₂ and 4b ₂ each have a primary winding with a center tap.

Incidentally, in the first primary winding of the transformer 4a _2, first
The outputs of the outer electrodes 3a and 3b of the vibrator 5a and the outputs of the inner electrodes 2c and 2d of the second vibrator 5b are connected in series and input. In this case, the outer electrode 3b of the first vibrator 5a and the inner electrode 2c of the second vibrator 5b are connected in series, and this series connection point is connected to the center tap.

Similarly, the second primary winding of the transformer 4b _2, the inner surface electrode 2a of the first oscillator 5a, the output and the outer surface electrode 3c of the second oscillator 5b of 2b, and the output of 3d connected in series The inner electrode 2b of the first vibrator 5a and the outer electrode of the second vibrator 5b
The series connection point with 3c is connected to the center tap.

With this configuration, as in the first embodiment, without compensating for phase inversion due to the difference in electrodes,
Even when flexural resonance occurs, the cosine (cos) of the incident azimuth θ of the incoming sound wave is applied to the secondary windings of the first and second transformers.
dipole V _Y of the Y-direction component proportional to the dipole signal V _X and the incident orientation theta sine of X-direction component proportional to θ) (sinθ) is output normally. Also, an omnidirectional omni signal V _OMN is obtained from the center tap of the primary winding of the first and second transformers.

As a fourth embodiment of the present invention, a third vibrator having one cylindrical piezoelectric body shown in FIG. 2 is used, and a transformer is used in the same manner as in the third embodiment shown in FIG. The same effect can be obtained even if the connection is made. Since the content is self-evident, the description is omitted.

〔The invention's effect〕

As described above, according to the present invention, the first and second vibrators each having the inner electrode and the outer electrode divided into two equal parts on the inner and outer peripheral surfaces of the cylindrical piezoelectric body so that the dividing directions are orthogonal to each other are provided in the opposite directions. The output of the outer surface electrode and the output of the inner surface electrode are combined by a transformer so that even if the frequency to be measured becomes wider, Disturbance of dipole directivity due to flexural resonance generated in the circumferential direction of the child can be compensated, and compensation for phase inversion due to the difference in electrodes can be eliminated to enable high-accuracy azimuth measurement with a small azimuth error over a wide band.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention, FIG. 2 is a block diagram of a vibrator showing a second embodiment of the present invention, and FIG. 3 is a third embodiment of the present invention. FIG. 4 is a diagram showing an example of a conventional electro-acoustic transducer, and FIG. 5 is a diagram showing the directional characteristics of a dipole signal when flexural resonance occurs. 1a, 1b, 1c ... Cylindrical piezoelectric body, 2a, 2b, 2c, 2d, 2e, 2f, 2g, 2h ...
… Internal electrodes, 3a, 3b, 3c, 3d, 3e, 3f, 3g, 3h …… external electrodes, 4
a ₁ , 4a ₂ … first transformer, 4b ₁ , 4b ₂ … second transformer, 5a… first vibrator, 5b… second vibrator, 5c…
Third vibrator, 10a, 10b... Polarization directions.

Claims (3)

(57) [Claims] 1. An inner peripheral surface of a cylindrical piezoelectric body is provided so as to face the inner surface.
An inner surface electrode divided into equal parts is provided, and an outer surface electrode divided into two parts is provided on an outer peripheral surface of the cylindrical piezoelectric body so as to be orthogonal to and opposed to a dividing direction of the inner surface electrode. A first vibrator subjected to polarization processing in a predetermined direction on the piezoelectric body, an inner surface electrode and an outer surface electrode formed in the same manner as the first vibrator, and the cylindrical piezoelectric member of the first vibrator; A second vibrator that is polarized in a direction opposite to that applied to the body, and is stacked and disposed on the central axis of the first vibrator at a position shifted by 90 degrees from each other; It has two primary windings provided with taps, one primary winding is connected to the output of each divided outer surface electrode of the first vibrator, and the other primary winding is connected to the second primary winding. The output of each of the divided inner electrodes of the vibrator is connected to the outer electrode of the first vibrator. Output and said second
A first transformer in which a differential combined output of the output of the inner surface electrode of the vibrator is generated in a secondary winding, and two primary windings each provided with a center tap, and one of the primary windings The output of each divided inner surface electrode of the first vibrator is connected to the other primary winding, and the output of each divided outer surface electrode of the second vibrator is connected to the other primary winding. The output of the inner electrode of the first vibrator and the second output
A second transformer in which a differential combined output of the output of the outer surface electrode of the vibrator is generated in the secondary winding; and a non-directional omni-directional omni-directional between the center taps of the first and second transformers. An electroacoustic transducer, wherein a signal is generated. 2. An inner peripheral surface of a cylindrical piezoelectric body,
An inner surface electrode divided into equal parts is provided, and an outer surface electrode divided into two parts is provided on an outer peripheral surface of the cylindrical piezoelectric body so as to be orthogonal to and opposed to a dividing direction of the inner surface electrode. A first vibrator subjected to polarization processing in a predetermined direction on the piezoelectric body, an inner surface electrode and an outer surface electrode formed in the same manner as the first vibrator, and the cylindrical piezoelectric member of the first vibrator; A second vibrator, which is polarized in a direction opposite to that applied to the body, is stacked and disposed on the central axis of the first vibrator so as to be shifted by 90 degrees from each other, One output of the divided outer surface electrode of the first vibrator is connected to one terminal of the primary winding, and the other terminal of the primary winding is connected to the other terminal of the primary winding. The output of one of the divided inner surface electrodes of the two vibrators is connected to the center tap. The other output of the outer electrode of the first vibrator and the other output of the second inner electrode are connected to each other to output the inner electrode of the first vibrator and the outer surface of the second vibrator. A first transformer in which a differential combined output of the electrodes is generated in a secondary winding, and a primary winding with a center tap, and one terminal of the primary winding is connected to the first vibrator. One output of the divided inner surface electrode is connected, the other terminal of the primary winding is connected to one output of the divided outer electrode of the second vibrator, and the center tap is connected to the center tap. The other output of the inner electrode of the first vibrator and the other output of the outer electrode of the second vibrator are connected to each other to output the output of the inner electrode of the first vibrator and the second vibrator. The differential output of the output of the outer electrode of the second is generated in the secondary winding. And an omni-directional omni signal is generated between the center taps of the first and second transformers. 3. An electroacoustic transducer according to claim 1, wherein said first and second vibrators are formed of the same cylindrical piezoelectric body.