JPH05300584

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DESCRIPTION JPH05300584
[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an
ultrasonic transducer, more specifically, to emit ultrasonic waves in all directions by a large
number of transducer elements arranged in a cylindrical shape, and to receive signals from
reflected waves thereof. The present invention relates to an ultrasonic transducer such as a socalled scanning sonar that forms directivity in a specific direction by phase synthesis and detects
a fish school or the like.
[0002]
2. Description of the Related Art A conventional ultrasonic transducer of this type arranges a
large number of piezoelectric ceramic transducer elements (for example, PZT: lead zirconate
titanate) in a cylindrical shape, and transmits and receives signals of each of the transducer
elements. Phase combining, the transmitting wave is omnidirectional in the horizontal direction
and narrow directivity in the vertical direction, and the receiving wave forms narrow directivity
in both horizontal and vertical directions, and the configuration can perform underwater
detection in a wide range of directions. There is.
[0003]
FIG. 2A shows the structure of an example of a conventional ultrasonic transducer, and FIG. 2B
shows the cross-sectional structure taken along the line A-A 'of FIG.
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A large number of transducer elements 1 are arranged in a cylindrical shape, and surfaces other
than the ultrasonic radiation surface are covered with a sound insulating material 2 to avoid
transmission and reception from unnecessary directions, and electrodes 3 provided on both sides
of the transducer elements 1 A signal line 4 for transmitting and receiving a transmission /
reception signal is drawn inside the cylinder. The spacing between the transducer elements 1 is
usually λ / 2 in order to suppress so-called side lobes having sensitivity in unnecessary
directions when forming directivity by phase synthesis.
[0004]
SUMMARY OF THE INVENTION If the transducer radiation area is large, the amount of energy
transmitted or received by the transducer can be exchanged, and the radiation area can be
detected particularly by scanning sonar etc. It greatly affects the performance. However, the
dimensions of the sound insulation material provided between the transducer elements must
satisfy the sound insulation performance and the withstand voltage between the adjacent
transducer element electrodes, and the conventional device can not be made much smaller. There
is a problem that the detection distance performance is lowered as the area can not be made
large, particularly as the use frequency is increased.
[0005]
The present invention has been made to solve the above problems, and provides an ultrasonic
transducer having a structure that can widen the radiation area of the transducer without
causing a decrease in the sound insulation performance and the withstand voltage between the
transducer elements. The purpose is to
[0006]
SUMMARY OF THE INVENTION An ultrasonic wave receiver according to the present invention is
a doughnut-shaped vibrator or ring-shaped piezoelectric ceramic formed by arranging a large
number of arc-shaped piezoelectric ceramic vibrators oscillating in the radial direction. A vibrator
for transmitting wave having a large ultrasonic wave radiation area is configured by laminating
vibrators through a sound insulating material and arranging in a cylindrical shape, and a phase
of reception on the front of a radiation surface of the above-mentioned cylindrical wave
transmitting vibrator. Acoustically transparent film-like piezoelectric material that forms a
pattern with high electrode density that maintains the spacing of λ / 2 at the top, bottom, left,
and right to suppress side lobes when forming directivity by synthesis A method of cylinder A
transducer for reception having a wide ultrasonic wave reception area is configured by arranging
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in two layers while keeping an interval of λ / 4 with respect to the linear direction.
[0007]
In the ultrasonic transducer according to the present invention, a doughnut-shaped vibrator or
ring-shaped piezoelectric ceramic vibrator in which a plurality of wave transmitting vibrators are
arranged by arranging a plurality of arc-shaped piezoelectric ceramic vibrators is laminated.
Since the configuration is made by arranging in a cylindrical shape, it is possible to reduce the
portion of the sound insulation material that has conventionally existed in the cylindrical
direction, and to widen the ultrasonic radiation area.
On the other hand, in the wave receiving transducer, the withstand voltage between the adjacent
array electrodes can be almost ignored, so a wide wave receiving area can be obtained.
Moreover, directivity equivalent to the case of using a sound insulation material can be obtained.
[0008]
Embodiments of the present invention will be described hereinbelow with reference to the
drawings. FIG. 1 (a) shows the structure of an embodiment of the present invention, and FIG. 1
(b) shows the cross-sectional structure taken along the line B-B 'of FIG. 1 (a). The ring-shaped
piezoelectric ceramic vibrator 5 is stacked via the sound insulation material 2 and arranged in a
cylindrical shape to constitute a vibrator for transmitting wave, and the horizontal and vertical
directions are made in front of the radiation surface of the cylindrical wave transmitting vibrator.
In order to suppress side lobes when forming directivity by phase synthesis, the film-like
piezoelectric material 6 with good sound permeability forming a pattern with a high electrode
density keeping an interval of λ / 2 in the vertical and horizontal directions 7 is molded with a
sound wave transmitting material 8 and arranged in two layers to constitute a transducer for
receiving wave.
[0009]
Since the piezoelectric materials 6 and 7 are acoustically transparent, they have no effect on the
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transmission output. Since a large ultrasonic power is usually required for the ring-shaped
vibrator 5 for wave transmission, ceramic vibrators such as PZT (lead zirconate titanate) and
BaTiO3 (barium titanate) with good injection power performance are used. As for the wave, since
any material having good acoustic-electrical conversion performance may be used, the
piezoelectric films 6 and 7 which can obtain a wide receiving area are effective. As a material of
the piezoelectric film, piezoelectric rubber, PVDF (poly (vinylidene fluoride)) or the like can be
considered. Further, the holding of the piezoelectric films 6 and 7 of the wave receiving vibrator
disposed on the ultrasonic wave radiation surface is made of the sound wave transmitting
material 8 such as neoprene rubber or urethane rubber.
[0010]
Assuming that the receiving piezoelectric film is a single layer, one of the electrodes (one
element) has sensitivity to the outside and the inside of the cylinder, and it is from the
transmitting transducer inside. Unfavorably affected by reflected waves. Therefore, it has a twolayer structure of λ / 4 intervals, and has a so-called end fire array configuration in which the
sensitivity inside the cylinder is suppressed by shifting the phases by π / 4 and adding them. In
this way, the directivity characteristic of the endfire array of the two-element configuration
shown in FIG. 3 is obtained, and one directivity of the piezoelectric vibrator 1 used in the
conventional ultrasonic transducer as shown in FIG. 4 is obtained. Comparable performance can
be obtained compared to the characteristics.
[0011]
In the above embodiment, an example in which the transmitting vibrator is configured using the
ring-shaped piezoelectric ceramic vibrator 5 is shown, but the invention is not limited thereto,
and a large number of divided piezoelectric ceramics are used. It goes without saying that the
same effect can be obtained by using a vibrator to form a doughnut-shaped vibrator and
laminating the vibrator.
[0012]
As described above, according to the present invention, there is an advantage that the
transmitting radiation area and the receiving area can be widely configured without lowering the
sound insulation performance and the withstand voltage between the transducer elements.
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Further, since techniques such as printing can be used to form the wave receiving vibrator, there
is an advantage that the electrode pattern arrangement for side lobe suppression can be made
highly accurate.
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