GB2521762A

GB2521762A - Ultrasonic transmitting and/or receiving device

Info

Publication number: GB2521762A
Application number: GB1422030.5A
Authority: GB
Inventors: Yasushi Miki; Akinori Nakamoto; Yuji Ishikawa; Nobuo Suzuki; Eiji Murakami; Kouki Tanaka
Original assignee: Furuno Electric Co Ltd
Current assignee: Furuno Electric Co Ltd
Priority date: 2013-12-27
Filing date: 2014-12-11
Publication date: 2015-07-01
Anticipated expiration: 2034-12-11
Also published as: GB2521762B; JP6353224B2; JP2015125110A

Abstract

An ultrasonic device 2 comprises an ultrasound transducer 10, a frustum shaped resonator or diaphragm 11 has front surface 12 as the output, the rear surface 13 interfaces with electrostrictive elements 15a/b. A rear portion 16 sandwiches the electrostrictive devices to the resonator and a frame 20 holds one or both of the rear portion and the electrostrictive device. An elastic part 25 which may be made of rubber or resin surrounds the side of the resonator forward of the frame and may fully encapsulate the resonator. Alternatively electrically insulating oil may cover the front surface of the resonator. The device may be arranged into a rectangular or circular array which may in turn be used in an underwater detection system incorporating a signal processor and display.

Description

Ultrasonic Transmitting and/or Receiving Device, Underwater Detection Apparatus, and Method for Manufacturing Ultrasonic Transmitting and/or Receiving Device

FIELD OF THE INVENTION

[0001]Tbe present invention relates to an ultrasonic transmitting and/or receiving device, an underwater detection apparatus with the ultrasonic transmitting and/or receiving device, and a method for manufacturing the ultrasonic transmitting and/or receiving device.

BACKGROUND OF THE INVENTION

[0002]Conventional transmitting and receiving devices have been known, which are comprised with ultrasound transducers for emitting and receiving ultrasonic waves. For instance, there is disclosed in a registered Japanese Utility Model No. 2561086 a transmitting and receiving device wherein ultrasound transducers are inserted respectively into a plurality of holes formed as in a honeycomb fashion in a back plate or in a frame unit so that a plurality of ultrasound transducers are disposed in the frame unit.

[0003]But, when ultrasound transducers are inserted into holes in the frame unit as explained above, there is a possibility that a holding power for the transducers will be insufficient and thus, a sufficient pressure resistance for the transducers cannot be obtained.

[0004]lt is also thought that ultrasound transducers are fixedly held in the frame unit through 0-rings therebetween. With this arrangement, there is a possibility that necessary pressure resistance will be insufficient.

SUMMARY OF THE INVENTION

[0005]Accordingly, the present invention aims to address the aforementioned problems. An object of the invention is to increase pressure resistance for the ultrasound transducers fixedly held in the frame.

According to a first aspect of the present invention, there is provided an ultrasonic transmitting and/or receiving device according to claim 1.

According to a second aspect of the present invention, there is provided a method according to claim 19.

Preferred features of the invention are recited in the dependent claims.

[0006]One aspect of the present invention is to provide an ultrasonic transmitting and receiving device which comprises an ultrasound transducer which is comprised with a front portion having a transmission and reception surface on the front side thereof for transmitting and receiving ultrasonic waves, at least one electrostrictive element disposed on the back edge surface of the front portion, a rear portion for holding with the front portion the electrostrictive element therebetween, a frame unit supporting one or both of the rear portion and the electrostrictive element, and an elastic portion having elastic characteristics, wherein the front portion includes a cross-sectional area decreasing part in which the cross-sectional area of the back edge surface of the front portion is smaller as compared to the one of the transmission and reception surface, and wherein the elastic portion having expanding and contracting characteristics is provided between the side surface of the cross-sectional area decreasing part and the frame unit.

[0007] Preferably, the side surface of the cross-sectional area decreasing part is a taper surface expanding from the back edge surface of the front portion to the transmission and reception surface in slant directions.

[0008]Preferably, the ultrasonic transmitting and receiving device is further provided with a sound insulation material between the side surface of the cross-sectional area decreasing part and the elastic portion.

[0009]Preferably, the ultrasonic transmitting and receiving device is further provided with an insulation part which is made of a material having electric insulation characteristics and covers the transmission and reception surface.

[0010]Preferably, the elastic portion and the insulation part together are made from material having electric insulation and elastic characteristics.

[0011]Preferably, the ultrasonic transmitting and receiving device comprises a plurality of the ultrasound transducers as the ultrasound transducer [0012]Preferably, the transmission and reception surface of each of the ultrasound transducers is shaped in a rectangular form, and a plurality of the ultrasound transducers constitute transducer rows with each row having ultrasound transducers disposed on an imaginary line, and with the long side of the transmission and reception surface thereof being along the imaginary line, and a plurality of the ultrasound transducer rows disposed on an imaginary circular line with the short side of the transmission and reception surface of the ultrasound transducer being along the circular line in a circumference direction.

[0013]Preferably, the ultrasound transducers constituting one of the respective ultrasound transducer rows are displaced in the same direction as that of the long side of the transmission and reception surface with respect to the corresponding ones of an adjacent row of the transducers.

[0014]Preferably, the ultrasonic transmitting and receiving device further comprises a cover member made from material having electric insulation characteristics which is disposed between one of or both of the rear portion of the transducer and the electrostrictive element, and the frame unit.

[0015] Preferably, the elastic portion is made of resin material or rubber material.

[0016]An underwater detection apparatus configured to detect objects in the water according to an aspect of the present invention is comprised with one of the ultrasonic transmitting and receiving devices described above configured to transmit ultrasonic waves into the water and receive echo ultrasonic waves therefrom, a signal processing unit configured to process reception signals outputted from the transmitting and receiving device to generate echo image signals, and a display unit configured to display the echo image signals generated by the signal processing unit.

[0017]A method for manufacturing an ultrasonic transmitting and receiving device according to an aspect of the present invention includes an ultrasound transducer which is comprised with a front portion having a transmission and reception surface on one side thereof for transmitting and receiving ultrasonic waves, at least one electrostrictive element disposed, on the other side thereof, on the back surface of the front portion, and a rear portion for holding with the front portion the electrostrictive element therebetween, wherein the front portion includes a cross-sectional area decreasing part in which the cross-sectional area of the back edge surface of the front portion is smaller as compared to the one of the transmission and reception surface, step for supporting one or both of the rear portion and the electrostrictive element, and step for providing an elastic portion having expanding and contracting characteristics between the side surface of the cross-sectional area decreasing part and the frame unit.

[0018]Preferably, the step for providing an elastic portion fills material for making the elastic portion between the side surface of the cross-sectional area decreasing part and the frame unit (for example by molding), with the ultrasound transducer for supporting one of or both of the rear portion and the electrostrictive element in the frame unit.

[0019]According to another aspect of the present invention, an ultrasonic transmitting and receiving device comprises a ultrasound transducer; a frame unit having a hole and supporting the ultrasound transducer at one side of the ultrasound transducer which is put into the hole, and an elastic portion provided between the other side of the ultrasound transducer and the frame unit so that the ultrasound transducer is fixedly held by the frame unit.

[0020]According to another aspect of the invention, an ultrasonic transmitting and receiving device comprises a plurality of ultrasound transducers, a frame unit having holes and supporting the ultrasound transducers respectively at one side of the ultrasound transducers which are put into the holes, and an elastic portion provided between the other side of the ultrasound transducers and the frame unit so that the ultrasound transducers are fixedly held by the frame unit.

[0021]The present invention will increase pressure resistance for the ultrasound transducers held in the frame unit.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022]Fig. 1 shows a block diagram of the arrangement of an underwater detection apparatus, according to an embodiment of the present invention; [0023]Fig.2 shows schematically the shape of an ultrasonic transmitting and receiving device shown in Fig. 1; [0024]Fig. 3 shows a part of an amplified frame unit of the transmitting and receiving device shown in Fig. 2 which is developed so that the outer surface of the frame unit will be a planar one. There is shown schematically the arrangement of a plurality of holes for transducers formed on the outer surface of the frame unit; [0025]Fig. 4 shows a partial section side view of an ultrasound transducer embedded in the frame unit and the mold portion; [0026]Fig.5 shows a flow chart illustrating steps for manufacturing the ultrasonic transmitting and receiving device; [0027]Fig. 6 shows a transmitting and receiving device according to another embodiment of the invention seen from the outside in a radial direction of the device, which is used for explaining the shape of the transmission and reception surface of the ultrasound transducer; [0028]Fig. 7 shows a transmitting and receiving device according to another embodiment of the invention seen from the outside in a radial direction of the device, which is used for explaining the arrangement of a plurality of the ultrasound transducers; [0029]Fig. 8 shows a transmitting and receiving device according to another embodiment of the invention for explaining the construction thereof, which corresponds to the one in Fig. 4; [0030]Fig. 9 shows a transmitting and receiving device according to another embodiment of the invention for explaining the construction thereof, which corresponds to the one in Fig. 4; and [0031]Fig. 10 shows a transmitting and receiving device according to another embodiment of the invention for explaining the construction thereof, which corresponds to the one in Fig. 4.

DETAILED DESCRIPTION OF THE INVENTION

[0032]Hereinafter, there will be explained, referring to drawings, an underwater detection apparatus 1 having an ultrasonic transmitting and receiving device according to one embodiment of the present invention. The underwater detection apparatus 1 is primarily used for detecting targets such as a fish or a school of fish. The ultrasonic transmitting and receiving device 1 is fixed on the bottom of the ship as exposed in the water.

[0033]Fig. 1 shows a block diagram of the construction of an underwater detection apparatus 1, according to an embodiment of the present invention. The underwater detection apparatus 1 is comprised with an ultrasonic transmitting and receiving device 2, a transmitting and receiving device 3, a signal processing unit 4 and an operation and display device 5.

[0034]Tbe ultrasonic transmitting and receiving device 2 is comprised with a plurality of ultrasonic transducers 10. With the ultrasonic transmitting and receiving device 2, respective ultrasonic transducers 10 emit ultrasonic waves at predetermined timings respectively into the water, with the ultrasonic waves having been converted from electric signals. The ultrasonic transducers 10 also convert ultrasonic waves to electric signals. There will be explained about the arrangement of the ultrasonic transmitting and receiving device 2 in detail later.

[0035]The transmitting and receiving device 3 is comprised with a transmission and reception switching unit 6, a transmission unit 7 and a reception unit 8. In transmission, the transmission and reception switching unit 6 is switched to connect the transmission unit 7 with the ultrasonic transmitting and receiving device 2 so that transmission signals will be supplied to the ultrasonic transmitting and receiving device 2 from the transmission unit 7. In reception, the transmission and reception switching unit 6 is switched so that electric signals converted from ultrasonic waves by the ultrasonic transmitting and receiving device 2 will be supplied to the reception unit 8.

[0036]Tbe transmission unit 7 generates transmission signals to meet conditions determined by the operation and display device 5, and supplies the resultant signals to the transmitting and receiving device 2 through the transmission and reception switching unit 6.

[0037]Tbe reception unit 8 amplifies echo signals received by the transmitting and receiving device 2, and converts the amplified analog reception signals to digital signals. Then, the reception unit 8 outputs the resultant digital signals to the signal processing unit 4.

[0038]The signal processing unit 4 processes reception data outputted from the reception unit 8 to generate display signals representing targets.

[0039]Tbe operation and display device 5 displays images on the screen of an indicator in response to image signals outputted from the signal processing unit 4. A user looks at the screen of the indicator and can presume underwater conditions such as a single fish or a school of fish being in the area surrounding the own ship. The operation and display device 5 is comprised with input means having various input keys and the like, and is configured to provide various necessary settings or to input various parameters for transmitting and receiving ultrasonic waves, processing signals or displaying images.

[0040] Fig.2 shows schematically an ultrasonic transmitting and receiving device 2. Fig. 3 shows a part of an amplified frame unit 20 of the transmitting and receiving device 2 shown in Fig. 2 in which the outer surface 21 of the frame unit is developed to be a planar one. Fig. 3 shows schematically the arrangement of a plurality of holes 22 for transducers formed on the outer surface 21 of the frame unit 20. Fig. 4 shows a partial section side view of an ultrasound transducer embedded in the frame unit 20 and a mold portion 25. It is to be noted that hereinafter, for the sake of explanation, there are cases in which the direction of an arrow represented as up' may be called upper side' or upward'.

Also, the direction of an arrow represented as down' may be called lower side' or downward'. The direction of an arrow represented as front' may be called front side' or frontward'. The direction of an arrow represented as back' may be called back side' or backward'.

[0041]Tbe transmitting and receiving device 2 is, as shown in Fig. 2, shaped substantially in a form of column. The outer diameter of the transmitting and receiving device 2 is, for instance, about 530 mm. The transmitting and receiving device 2 is installed on the hull of the ship in such a way that the device is exposed in the water and the center axis thereof is aligned with the vertical direction. The transmitting and receiving device 2 is comprised with the frame unit 20, the mold portion 25 and a plurality of the ultrasound transducers 10 as shown in Figs. 2 and 4.

[0042]The frame unit 20 is made of metal and shaped substantially in a form of column. On the outer surface 21 of the frame unit 20 there are formed a plurality of holes 22 into which ultrasound transducers 10 are inserted respectively, as shown in Figs. 3 and 4. Each hole 22 for a transducer is formed in such a way that the hole 22 is shaped extending from the outer surface 21 of the frame unit towards the inner side in a radial direction. The hole 22 for the transducer is shaped in a form of circle in a plane sectioned in a direction perpendicular to the direction in which the hole 22 for the transducer extends.

[0043] Referring to Fig. 3, there are formed on the outer surface 21 of the frame unit 20 a plurality of a series of the holes 23 for the transducers at predetermined distance intervals on an imaginary straight line in the up and down direction, which are disposed in a circumference direction at equal distances therebetween. The whole of the plurality of the holes 22 for transducers consist of the plurality of the rows of the holes 23 arranged as explained above. The plurality of the holes 22 for transducers are arranged on imaginary straight lines respectively both in the up and down direction and in the circumference direction as seen from the outside in the radial direction. Thus, a plurality of the holes 22 for the transducers are arranged in a grid or matrix fashion. The distance between adjacent center points of the holes 22 for transducers in a circumference direction is set a distance so that grating lobes as will be explained later will not be generated. With the present embodiment, the distance is below halt of the wavelength USA of the ultrasonic waves.

[0044]Tbe ultrasound transducer 10 is comprised with a main transducer body 1 Oa and a cover material 19 as shown in Fig. 4.

[0045] The main transducer body 1 Oa is comprised with a front portion or a front mass 11, two electrostrictive elements 1 Sa and 1 Sb, and a rear portion or a rear mass 16. The main transducer body ba is a bolted langevin type transducer called as a BLT transducer having the front mass 11, the electrostrictive elements 15a and 15b, and the rear mass bolted to be fixed with one another With the main transducer body ba, as shown in Fig. 4, the electrostrictive elements 1 5b and isa, the front mass 11 are disposed sequentially with respect to the rear mass 16 fixed to the frame unit 20, from the center of the ultrasonic transmitting and receiving device 2 to the outside in a radial direction thereof.

[0046]Tbe front mass 11 is made of a metal material such as aluminum and in a form of block. As shown in Fig. 4, the front mass 11 is successively expanded from the inner side to the outer side of the ultrasonic transmitting and receiving device 2 in a radial direction thereof. The front surface of the front mass 11 functions as the transmission and reception surface 12 to emit and receive ultrasonic waves. The back edge surface of the front mass 11 is the back surface 13 of the front mass.

[0047]The transmission and reception surface 12 is shaped to be flat, and is configured to be directed forward. The transmission and reception surface 12 is shaped as rectangle having a long side in the up and down direction as shown in Fig.2. The length of the long side thereof is, for instance, about 47 mm, while, the length of the short side thereof is, for instance, about 26 mm.

[0048]The front mass 11 includes a cross-sectional area decreasing portion ha in which the cross-sectional area decreases gradually from the one of the transmission and reception surface 12 to that of the back edge surface 13 of the front mass. The side of the cross-sectional area decreasing portion 11 a is shaped as a curved taper surface 14 expanding from the back edge surface 13 of the front mass toward the transmission and reception surface 12. The curved taper surface 14 is directed to the frame unit 20, when the ultrasound transducer is fixed in the frame unit 20.

[0039]The two electrostrictive elements iSa and 15b are configured to be shaped substantially toric with the outer diameter and thickness thereof being almost the same, and to expand and contract in response to voltages applied to vibrate in their axis direction. The two electrostrictive elements isa and lSb are disposed on an imaginary line with the one element being stacked on the other element, as shown in Fig. 4.The edge surface of the front element iSa is firmly fixed on the back surface 13 of the front mass, while the edge surface of the back element 1 Sb is firmly fixed to the front surface 17 of the rear mass 16.

[0040]The rear mass 16 is shaped substantially in a form of column with its outer diameter being a little larger than those of the electrostrictive elements isa and 15b and its length being longer than those of the elements. The rear mass 16 is made, for instance, of a metal as stainless steel, SUS and the like. The rear mass i6 is disposed on the imaginary axis line of the electrostrictive elements 1 5a and 1 Sb, and the front surface 17 thereof is firmly fixed to the back surface of the electrostrictive element lSb. The back surface of the rear mass 16 is connected to a connector i8 which is fixed in the frame unit 20. The connector 18 is used to supply the electrostrictive elements 15a and 15b with voltages through a cable (not shown) connected to the elements 1 5a and 1 5b.

[0041]A cover material 19 is made of an electric insulating and sound insulating member such as sponge or cork and the like. The cover material i9 covers the whole outer surface of the main transducer body ba except the transmission and reception surface 12 and the back edge surface of the rear mass 16, as shown in Fig. 4. The cover material 19 is shaped in a band-like form and is wound around the outer surface of the main transducer body ba. The cover material i9 covering the taper surface 14 works as sound insulating material to assure sound insulation between the taper surface 14 and the mold portion 25.

The arrangement prevents ultrasonic waves generated by an ultrasound transducer 10 from propagating outward through the taper surface 14. Thus, ultrasonic waves are emitted from the transmission and reception surface 12.

[0042]A plurality of the ultrasound transducers 10 constructed as above explained are held respectively in the holes 22 for transducers formed in the frame unit 20. Specifically, each ultrasound transducer iO is moved in such a way as the long side of the transmission and reception surface i2 is in parallel with the up and down direction so that the rear mass 16 is inserted into a hole 22 for a transducer. The outer surface of the rear mass 16 is covered with a sponge-like cover material i9 so that the frame unit 20 holds the rear mass i6 through the cover material 19. Further, the cover material 19 is made of a material having electric insulation characteristics. Thus, the rear mass i6 and the frame unit 20 are electrically isolated from one another by the arrangement having the cover material 19 between the rear mass 16 and the frame unit 20.

[0043]Tbe ultrasound transducers 10 are inserted into a plurality of the holes 22 for transducers and held respectively. Thus, the arrangement of ultrasound transducers 10 seen from the outside in a radial direction thereof will be the same as the one of the holes 22 for a plurality of transducers.

[0044]A plurality of the ultrasound transducers 10 are disposed at predetermined distance intervals in the up and down direction to have a row 9 of transducers. And a plurality of the rows 9 of transducers are disposed at equal distance intervals in a circumference direction so that the ultrasound transducers are disposed in the frame unit 20. The ultrasound transducers 10 forming the rows 9 of ultrasound transducers are disposed on imaginary straight lines both in the up and down direction and in the circumference direction and thus the transducers are disposed in a grid or matrix fashion. The distance interval between the center points of two adjacent ultrasound transducers 10 disposed on a straight line in a circumference direction is set below half of the wavelength, 0.5A of ultrasonic waves. In this way, the ultrasound transducers 10 are disposed at comparatively narrower distance intervals, particularly in the circumference direction.

[0045]The mold portion 25 is disposed around the outer surface of the frame unit 20 and shaped substantially in a cylinder form, as shown in Figs. 2 and 4.

The mold portion 25 works as an elastic body made from material having elastic and electric isolation characteristics. It is preferable that the mold portion 25 is made of a material having an acoustic impedance close to that of the water or seawater. The arrangement will enable ultrasonic waves to efficiently propagate from the ultrasound transducer 10 to the water. The mold portion 25 is preferably made of elastic materials such as, for instance, foaming urethane, rubber material or epoxy resin and the like.

[0046]The mold portion 25 is provided which extends from the outer surface 21 of the frame unit 20 to the outside of the transmission and reception surface 12.

This arrangement will enable the mold portion 25 to be mounted between the taper surface 14 and the frame unit 20 so that the taper surface 14 is held from the back thereof with respect to the frame unit 20.

[0047]Tbe mold portion 25 covers the transmission and reception surfaces 12 of a plurality of the ultrasound transducers 10. The mold portion 25 covering the transmission and reception surface 12 works as an electric insulation material having electric insulating characteristics. It assures that electric insulation is provided between the transmission and reception surface 12 and the outside such as the water or the seawater.

[0048]Fig. 5 shows a flow chart illustrating steps for manufacturing the transmitting and receiving device 2. Referring to Fig. 5, there will be explained the method for manufacturing the transmitting and receiving device 2.

[0049]At a step Si, the main transducer body ba is assembled. Referring to Fig. 4, more specifically, the two electrostrictive elements iSa and i5b stacked together are held by the back edge surface 13 of the front mass and the front edge surface 17 of the rear mass 16 and are fastened by a bolt (not shown).

Then, at a step 52, the cover material 19 is wound around the main transducer body ba. Thus, assembling an ultrasound transducer 10 is completed.

[0050]At a step S3, the ultrasound transducer 10 is put in the frame unit 20.

More specifically, the rear mass 16 of the ultrasound transducer 10 is press-fitted into a hole 22 for transducer of the frame unit 20. Here, the long side of the transmission and reception surface 12 should be in parallel with the up and down direction. At a step 53, all the ultrasound transducers 10 are mounted respectively in the holes 22 for transducers.

[0051]At a step S4, the frame unit 20 having all the ultrasound transducers 10 fixed therein is set in a mold (not shown). There will be shaped a space corresponding to the mold portion 25 between the mold and the frame unit 20 having the ultrasound transducer 10 fitted therein. At a step S5, urethane liquid is poured into the space and foamed so that the mold portion 25 will be shaped.

At a step 56, it is taken out from the mold so that the transmitting and receiving device 2 is completed.

[0052]lt has been known that a transmitting and receiving device for emitting and receiving ultrasonic waves, particularly a device installed in the bottom of the hull of a ship is affected by a pressure called as a slamming pressure caused when a ship moves up and down in navigation and collides on the sea surface, and also by shocks caused and acted thereto when the ship collides with objects floating in the water such as a driftwood. Accordingly, the ultrasonic transmitting and receiving device is required to have a resistance capability against such external forces. It a conventional method is used in which the ultrasound transducers are fixed to the frame unit using 0-rings, a resistance will be insufficient against the external forces.

[0053]With the transmitting and receiving device 2 according to embodiments of the present invention, an elastic portion as the mold portion 25 is provided between the frame unit 20 and the taper surface 14 of the cross-sectional area decreasing portion ha in which the cross-sectional area decreases gradually from the one of the transmission and reception surface 12 to that of the back edge surface 13 of the front mass. With the arrangement, the external forces ii against the transmitting and receiving device 2 are absorbed by the mold portion which is supported by the frame unit 20. This will increase pressure resistance of the transmitting and receiving device 2.

[0054]As in the foregoing, the transmitting and receiving device 2 used for the underwater detection apparatus 1 according to embodiments of the present invention, the mold portion 25 is provided between the frame unit 20 and the taper surface 14 which are on an imaginary straight line in the front and back direction. With this arrangement, external pressure and an external shock against the transmitting and receiving device 2 are absorbed by the mold portion 25 supported by the frame unit 20.

[0055]Accordingly, the transmitting and receiving device 2 will increase the pressure resistance of the ultrasound transducer 10 supported by the frame unit 20.

[0056]With the transmitting and receiving device 2, the whole taper surface 14 is held by the mold portion 25 so that the pressure resistance of the ultrasound transducer 10 will be further increased.

[0057] With the transmitting and receiving device 2, the frame unit 20 holding the rear mass 16 of the ultrasound transducer 10 is set in a mold into which urethane liquid is poured. The urethane liquid is foamed so that the mold portion 25 is shaped. This method makes it comparatively easy to form the mold portion 25. It is possible for the mold portion 25 to sufficiently adhere to the taper surface 14 and the frame unit 20 so that the ultrasound transducer 10 can be firmly fixed in the frame unit 20. Such a firm fixation of the ultrasound transducer 10 prevents a positional displacement of the ultrasound transducer 10 with respect to the frame unit 20 and a deformation thereof due to external forces against the transmitting and receiving device 2. This will decrease the risk of largely varying the characteristics of ultrasonic waves emitted by the ultrasound transducer 10.

[0058]With the transmitting and receiving device 2, resin materials are used for the elastic portion. More specifically, foam urethane is used. This makes it possible for the mold portion 25 to be easily formed by the mold method and to effectively absorb external forces acting on the ultrasound transducer 10. It is to be noted that other resin materials than foam urethane or rubber materials used for the elastic portion will produce similar effects.

[0059]With the transmitting and receiving device 2, the sound insulating part is provided between the taper surface 14 and the mold portion 25 so that ultrasonic waves generated by the electrostrictive elements isa and 15b are prevented from propagating through the taper surface 14 to the outside. Thus, ultrasonic waves can be efficiently transmitted from the transmission and reception surface 12.

[0060]With the transmitting and receiving device 2, the transmission and reception surface 12 is covered by the mold portion 25 having insulation characteristics so that there is obtained necessary insulation between the transmission and reception surface 12 and the seawater.

[0061]With the transmitting and receiving device 2, the mold portion 25 works as the elastic portion between the frame unit 20 and the taper surface 14 and as the insulation part covering the transmission and reception surface 12. Thus, the elastic portion and the insulation part can be shaped at one time.

[0062]With conventional transmitting and receiving devices, for instance, as one example, each of a plurality of ultrasound transducers is fixed in the frame unit through an 0-ring around the outer surface thereof. When a plurality of the ultrasound transducers are fixed in the frame unit, spaces will become necessary for having 0-rings between the outer surface of the ultrasound transducer and the frame unit. This arrangement will increase the distance between adjacent ultrasound transducers. If the distance between two adjacent ultrasound transducers becomes longer than half the wavelength of ultrasonic waves, grating lobes will be produced to cause to display false images on the screen of an indicator for an underwater detection apparatus.

[0063]While, with the transmitting and receiving device 2, the mold portion 25 is provided between the frame unit 20 and the taper surface 14 in the front and back direction. This arrangement does not require the spaces for the 0-rings to be used so that it will be easier to shorten the distance between adjacent ultrasound transducers, for instance, below half of the wavelength 0.5A. Thus, grating lobes are suppressed to be generated.

[0064]With the transmitting and receiving device 2, the transmission and reception surface 12 is shaped in a rectangular form. The ultrasound transducers 10 are disposed in such a way that the short side of the transmission and reception surface 12 is directed in a circumference direction, and the transducers are on an imaginary circle at shorter distance intervals between adjacent ultrasound transducers in the circumference direction. This arrangement will shorten distances between two adjacent transducers so that grating lobes are suppressed to be generated in the circumference direction.

[0065]With the transmitting and receiving device 2, the cover material 19 having electric insulation characteristics is provided between the rear mass 16 and the frame unit 20. Thus, the rear mass 16 and the frame unit 20 are easily and electrically insulated from one another.

[0066]With the transmitting and receiving device 2, the side surface of the cross-sectional area decreasing portion 11 a is formed as the taper surfacel 4.

This arrangement increases the cross-sectional area gradually from that of the back edge surface 13 of the front mass to the one of the transmission and reception surface 12. This makes it possible to secure sufficient bandwidth characteristics for ultrasonic waves emitted from the transmission and reception surface 12.

[0067]ln the foregoing, an embodiment of the present invention has been explained. Other embodiments thereof will be explained.

[0068]Fig. 6 shows a transmitting and receiving device 2a according to another embodiment of the invention seen from the outside in a radial direction of the device, which is used for explaining the shape of the transmission and reception surface 12a of the ultrasound transducer. With the ultrasound transducer 10 in the foregoing embodiment of the invention, the shape of the transmission and reception surface 12a is rectangular. But, the shape should not be limited to it.

More specifically, a circular one as shown in Fig. 6, is another shape of the transmission and reception surface 12a. Further, there are used other shapes such as a square, polygons as a hexagon and the like, and an elliplical one and the like.

[0069]Fig. 7 shows a transmitting and receiving device 2b according to another embodiment of the invention seen from the outside in a radial direction of the device, which is used for explaining the arrangement of a plurality of the ultrasound transducers. With the foregoing embodiment of the present invention, as shown in Fig. 2, a plurality of the ultrasound transducers 10 are disposed in a grid fashion. But, the invention should not be limited to only this one. More specifically, as shown in Fig. 7, a plurality of ultrasound transducers disposed on an imaginary straight line in an up and down diroction constituting a row of the ultrasound transducers can be displaced with respect to ultrasound transducers constituting an adjacent row of the transducers. As shown in Fig.7, this arrangement makes it easier for the ultrasound transducers to be disposed at center-to-center distance intervals below half of the wavelength U.5A between adjacent transducers in the up and down direction. This will suppress grating lobes in the up and down direction to be generated.

[0070]Fig. 8 shows a transmitting and receiving device 2c according to another embodiment of the invention for explaining the construction thereof, which corresponds to the one in Fig. 4. The arrangement of the embodiment of the invention is different from the foregoing embodiment in the shape of the mold portion 25. The transmitting and receiving device 2c is provided with insulation oil 26 for electrically insulating the transmission and reception surface 12 of the ultrasound transducer 10 from the outside.

[0071]The mold portion 25a of the embodiment is, in the same way as in the foregoing embodiment, made from material having elastic and electrically insulating characteristics and substantially in a form of cylinder But, the mold portion 25a is different from the foregoing embodiment in that the mold portion 25a extends from the outer surface 21 of the frame unit 20 to the transmission and reception surface 12. But, the transmission and reception surface 12 is not covered by the mold portion 25a.

[0072]The insulation oil 26 is filled in a container 27 disposed on the device distant from the mold portion 25a and the transmission and reception surfacel 2.

Thus, the transmission and reception surfacel 2 is insulated from the outside, the seawater.

[0073]The mold portion 25a according to this embodiment can be formed in the same way as with the foregoing embodiment. More specifically, the mold portion 25a is formed in the way that the frame unit 20 having a plurality of the ultrasound transducers fixed therein is set in the mold, and then urethane liquid is filled in the mold and foamed. The transmitting and receiving device 2c is manufactured in this way that the frame unit 20 with the mold portion 25a formed and the ultrasound transducers 10 are housed in the container 27 which is then filled with insulation oil 26.

[0074]lt is to be noted that the transmitting and receiving device 2c according to this embodiment can be manufactured in another way. More specifically, the mold portion 25a having been formed is fixedly attached to the outer surface 21 of the frame unit 20. Then, the ultrasound transducers 10 are inserted into a through-holes 25b formed in the mold portion 25a and into the holes 22 for transducers in the frame unit 20, and is fixed therein. The container 27 houses the resultant assembly and is filled with insulation oil 26.

[0075]Fig. 9 shows a transmitting and receiving device 2d according to another embodiment of the invention for explaining the construction thereof, which corresponds to the one in Fig. 4. With the foregoing embodiment of the invention, the frame unit 20 holds the rear mass 16 of the ultrasound transducer 10. But, the invention should not be limited to only this one. As shown in Fig. 9, it is also possible for the frame unit 20a to hold both the rear mass 16 and electrostrictive elements 15a and lSb. Further, it is possible to hold only the electrostrictive elements 1 5a and 1 5b by the frame unit. With this arrangement, the mold portion 25c will be formed in the front and back direction extending from the back edge surface 13 forward.

[0076]Fig. 10 shows a transmitting and receiving device 2e according to another embodiment of the invention for explaining the construction thereof, which corresponds to the one in Fig. 4. With the foregoing embodiment of the invention, the mold unit 25 provides with both the elastic portion and the insulation part covering the transmission and reception surface 12. But, the invention should not be limited to only this one. More specifically, as shown in Fig. 10, it is also possible to provide the elastic portion 28 between the taper surface 14 and the frame unit 20 in the front and back direction, and to form an insulation part 29 made from material different from the one of the elastic portion 28 in an area covering the transmission and reception surface 12.

[0077]Although embodiments according to the present invention are explained above wherein the ultrasonic transmitting and receiving device 2 is used for an underwater detection apparatus 1 for detecting objects in the water, applications of the present invention should nol be limfted 10 the underwater deteclion apparatuses. The present invention is also applicable to other systems using an ultrasonic transmitting and receiving device such as ultrasound diagnostic apparatuses.

[0078]Although embodiments according to the present invention are explained above wherein the ultrasonic transmitting and receiving device 2 is used which comprises a plurality of the ultrasound transducers 10, applications of the present invention should not be limited to this device only. The present invention is also applicable to other devices using one ultrasound transducer.

[0079]With tho forogoing embodimont of the invention, tho long side of the transmission and reception surface 12 is in the up and down direction and the short side thereof is in a circumference direction. But, the invention should not be limited to only the one. More specifically, it is also possible for the ultrasound transducers to be disposed such that the short side of the transmission and reception surface 12 is in the up and down direction and the long side thereof is in the circumference direction. Thus, a plurality of rows with each row including the transmission and reception surfaces 12 with the short side thereof being in the up and down direction are disposed at equal distance intervals in the circumference direction.

[0080]With the foregoing embodiment of the invention, the side surface of the cross-sectional area decreasing part ha is a taper surfacel4 expanding from the back edge surface 13 of the front mass portion to the transmission and reception surface 12 in slant directions. It is also possible for the side surface to be in a direction substantially perpendicular to the front and back direction representative of a direction from the transmission and reception surface 12 to the back edge surface 13 of the front mass.

[0081]Althougb the present invention has been fully described in connection with the preferred embodiments thereof with reference to the accompanying drawings, it is to be noted that various changes and modifications are apparent to those skilled in the art. Such changes and modifications are to be understood as included within the scope of the present invention as defined by the appended claims.

Claims

What is claimed is: 1. An ultrasonic transmitting and/or receiving device comprising: an ultrasound transducer comprising a front portion having a transmission and reception surface on the front side thereof for transmitting and/or receiving ultrasonic waves, at least one electrostrictive element disposed on a back edge surface of the front portion, and a rear portion for holding with the front portion the electrostrictive element therebetween; a frame unit supporting one or both of the rear portion and the electrostrictive element; and an elastic portion having elastic characteristics; wherein the cross-sectional area of the front portion decreases from the transmission and reception surface to the back edge surface and the elastic portion surrounds a side surface of the front portion which is forward of the frame unit.
2. The ultrasonic transmitting and/or receiving device of claim 1 wherein the elastic portion extends from the side surface to substantially fill a space between the transmission and reception surface and the frame unit.
3. The ultrasonic transmitting and/or receiving device of claim 2 wherein the elastic portion extends out of the space and extends from the frame unit by substantially the same distance as the transmission and reception surface.
4. The ultrasonic transmitting and/or receiving device of any preceding claim wherein the front portion is at least partially supported by the elastic portion.
5. The ultrasonic transmitting and/or receiving device of any preceding claim wherein at least a portion of the front portion is embedded in the elastic portion.
6. The ultrasonic transmitting and/or receiving device of any preceding claim wherein the elastic portion surrounds the front portion forward of the frame unit.
7. The ultrasonic transmitting and/or receiving device of any preceding claim which is arranged to transmit and/or receive ultrasonic waves through the elastic portion.
8. The ultrasonic transmitting and/or receiving device of any preceding claim which is arranged to transmit and/or receive ultrasonic waves through a portion separate from the elastic portion which is made from a material different from that of the elastic portion.
9. The ultrasonic transmitting and/or receiving device of any preceding claim wherein the side surface is a taper surface expanding from the back edge surface of the front portion to the transmission and reception surface in slant directions.
10. The ultrasonic transmitting and/or receiving device of any preceding claim wherein a sound insulation material is further provided between the side surface and the elastic portion.
11. The ultrasonic transmitting and/or receiving device of any preceding claim wherein there is further provided an insulation part which is made of a material having electric insulation characteristics and covers the transmission and reception surface.
12. The ultrasonic transmitting and/or receiving device of claim 11 wherein the elastic portion and the insulation part together are made from material having electric insulation and elastic characteristics.
13. The ultrasonic transmitting and/or receiving device of any preceding claim comprising a plurality of ultrasound transducers.
14. The ultrasonic transmitting and/or receiving device of claim 13, wherein the transmission and reception surface of each of the ultrasound transducers is shaped in a rectangular form; a plurality of the ultrasound transducers constitute transducer rows, each row having ultrasound transducers disposed on an imaginary line with the long side of the transmission and reception surface thereof being along the imaginary line; and a plurality of the ultrasound transducer rows are disposed on an imaginary circular line with the short side of the transmission and reception surface of the ultrasound transducer being along the circular line in a circumferential direction.
15. The ultrasonic transmitting and/or receiving device of claim 14, wherein the ultrasound transducers constituting one of the respective ultrasound transducer rows are displaced in the same direction as that of the long side of the transmission and reception surface as compared with the corresponding ones of an adjacent row of the transducers.
16. The ultrasonic transmitting and/or receiving device of any preceding claim further comprising a cover member made from material having electric insulation characteristics which is disposed between one of or both of the rear portion of the transducer and the electrostrictive element, and the frame unit.
17. The ultrasonic transmitting and/or receiving device of any preceding claim wherein the elastic portion is made of resin material or rubber material.
18. An underwater detection apparatus configured to detect objects in the water comprising: an ultrasonic transmitting and/or receiving device defined in any preceding claim configured to transmit ultrasonic waves into the water and receive echo ultrasonic waves therefrom; a signal processing unit configured to process reception signals from the ultrasonic transmitting and/or receiving device to generate echo images; and a display unit configured to display the echo images generated by the signal processing unit.
19. Method for manufacturing an ultrasonic transmitting and/or receiving device comprising an ultrasound transducer comprised with a front portion having a transmission and reception surface on one side thereof for transmitting and/or receiving ultrasonic waves, at least one electrostrictive element disposed, on the other side thereof, on a back edge surface of the front portion, and a rear portion for holding with the front portion the electrostrictive element therebetween; wherein the cross-sectional area of the front portion decreases from the transmission and reception surface to the back edge surface; the method comprising the steps of: supporting one or both of the rear portion and the electrostrictive element with a frame unit; and providing an elastic portion having expanding and contracting characteristics to surround a side surface of the front portion which is forward of the frame unit.
20. Method for manufacturing an ultrasonic transmitting and/or receiving device of claim 19, wherein the step of providing the elastic portion fills material for making the elastic portion between the side surface and the frame unit, with the ultrasound transducer for supporting one of or both of the rear portion and the electrostrictive element in the frame unit.
21. An ultrasonic transmitting and/or receiving device comprising: an ultrasound transducer; a frame unit having a hole and supporting the ultrasound transducer at one side of the ultrasound transducer which is put into the hole; and an elastic portion provided between the other side of the ultrasound transducer and the frame unit so that the ultrasound transducer is fixedly held by the frame unit.
22. An ullrasoriic Iransmitling and/or receiving device comprising: a plurality of ultrasound transducers; a frame unit having holes and supporting the ultrasound transducers respectively at one side of the ultrasound transducers which are put into the holes; and an elastic portion provided between the other side of the ultrasound transducers and the frame unit so that the ultrasound transducers are fixedly held by the frame unit.
23. An ultrasonic transmitting and/or receiving dovico substantially as shown in and/or as hereinbefore described with reference to the accompanying drawings.
24. A method for manufacturing an ultrasonic transmitting and/or receiving device substantially as shown in and/or as hereinbefore described with reference to the accompanying drawings.