GB2063007A - Ultrasonic transducer - Google Patents
Ultrasonic transducer Download PDFInfo
- Publication number
- GB2063007A GB2063007A GB8028490A GB8028490A GB2063007A GB 2063007 A GB2063007 A GB 2063007A GB 8028490 A GB8028490 A GB 8028490A GB 8028490 A GB8028490 A GB 8028490A GB 2063007 A GB2063007 A GB 2063007A
- Authority
- GB
- United Kingdom
- Prior art keywords
- ultrasonic
- ultrasonic transducer
- vibrator
- ultrasonic vibrator
- transducer
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- 229910052751 metal Inorganic materials 0.000 claims abstract description 14
- 239000002184 metal Substances 0.000 claims abstract description 14
- 239000000463 material Substances 0.000 claims description 15
- 229920001971 elastomer Polymers 0.000 claims description 12
- 230000002441 reversible effect Effects 0.000 claims description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims 1
- 239000012778 molding material Substances 0.000 abstract description 7
- 230000002706 hydrostatic effect Effects 0.000 abstract description 4
- JOYRKODLDBILNP-UHFFFAOYSA-N Ethyl urethane Chemical compound CCOC(N)=O JOYRKODLDBILNP-UHFFFAOYSA-N 0.000 abstract description 2
- 229920001084 poly(chloroprene) Polymers 0.000 abstract description 2
- 239000013536 elastomeric material Substances 0.000 abstract 1
- 239000013535 sea water Substances 0.000 description 7
- 230000010355 oscillation Effects 0.000 description 5
- 230000005540 biological transmission Effects 0.000 description 4
- 230000035945 sensitivity Effects 0.000 description 4
- JRPBQTZRNDNNOP-UHFFFAOYSA-N barium titanate Chemical compound [Ba+2].[Ba+2].[O-][Ti]([O-])([O-])[O-] JRPBQTZRNDNNOP-UHFFFAOYSA-N 0.000 description 3
- 229910002113 barium titanate Inorganic materials 0.000 description 3
- 241000234282 Allium Species 0.000 description 2
- 235000002732 Allium cepa var. cepa Nutrition 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 239000007799 cork Substances 0.000 description 2
- 230000003292 diminished effect Effects 0.000 description 2
- 229910001220 stainless steel Inorganic materials 0.000 description 2
- 239000010935 stainless steel Substances 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 230000002238 attenuated effect Effects 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- QNZFKUWECYSYPS-UHFFFAOYSA-N lead zirconium Chemical compound [Zr].[Pb] QNZFKUWECYSYPS-UHFFFAOYSA-N 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000003534 oscillatory effect Effects 0.000 description 1
- 230000000644 propagated effect Effects 0.000 description 1
Classifications
-
- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/002—Devices for damping, suppressing, obstructing or conducting sound in acoustic devices
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B06—GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS IN GENERAL
- B06B—METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, e.g. FOR PERFORMING MECHANICAL WORK IN GENERAL
- B06B1/00—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency
- B06B1/02—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy
- B06B1/06—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction
- B06B1/0644—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction using a single piezoelectric element
- B06B1/0662—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction using a single piezoelectric element with an electrode on the sensitive surface
- B06B1/0674—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction using a single piezoelectric element with an electrode on the sensitive surface and a low impedance backing, e.g. air
Abstract
An ultrasonic transducer for use in a sonar detector is disclosed. The ultrasonic transducer has a transducer element (18) backed by a layer (20) of elastomeric material, e.g. neoprene or urethane, and a metal plate (22). The thickness of the layer (20) and plate (22) lies in the range of 1/9 to 14/36 of the ultrasonic wave length ( lambda ) and the two are held by waterproof molding material (26). By these provisions, the front to back ratio, the hydrostatic pressure tightness, and the mechanical strength of the ultrasonic transducer is improved. <IMAGE>
Description
SPECIFICATION
Ultrasonic transducer
Background of the invention
A. Field of the invention
The present invention relates generally to ultrasonic transducer for use as sonar, or more particularly, to ultrasonic transducer which is superior in hydrostatic pressuretightness.
B. Description ofprior art
In sonar system that uses ultrasonic waves to detect and locate objects in the sea, ultrasonic transducer is utilized for transmitting and receiving ultrasonic waves. Ultrasonic transducer converts sound energy into electric energy and vice versa with the aid of, for example, barium titanate vibrator. Oscillatory type of vibrator can be assorted into lateral oscillation and longitudinal one.
In Figure 1, shown a prior art ultrasonic transducer in cross section. In the figure, numeral 10 indicates ultrasonic vibrator of barium titanate, numeral 12 indicates backing layer of cork or onion skin, numeral 14 indicates a cable and numeral 16 indicates a waterproof molding material. Backing layer 12 is provided at the back of plate-like ultrasonic vibrator 10 and they are united by waterproof molding material.
in such ultrasonic transducer, ultrasonic vibrator 10 oscillates when ultrasonic waves arrive in front of ultrasonic transducer as shown by an arrow A and then corresponding electric voltage is generated between wires of cable 14. On the contrary, oscillation of ultrasonic waves is attenuated by backing layer 12 when ultrasonic waves arrive at the back of ultrasonic transducer as shown by an arrow B, accordingly, oscillation is difficult to reach at ultrasonic vibrator 10 and only few electric voltage is generated.
As described, directivity is secured in ultrasonic transducer by providing backing layer 12 at the back of ultrasonic vibrator 10. But, directivity can be secured only when the acoustic impedance of backing material 12 of cork or onion skin is sufficiently smaller than that of acoustic medium such as sea water.
By the way, the ratio of receiving sensitivity by ultrasonic vibrator 10 to front waves to that of back waves is designated as front-to-back ratio. The front-to-back- ratio of ultrasonic transducer in Figure 1 is more than 20 dB when the depth of sea water ranges 100 to 200 meters. At the depth of 1,000 meters, however, attenuation ability of backing layer 12 is diminished. In other words, acoustic impedance is proportional to square root of Young's modulus, accordingly, Young's modulus (stiffness) is small in case that acoustic impedance of backing layer 12 is small. Thereby, backing layer 12 is compressed in deep sea water and attenuation ability of it is diminished.More precisely, the receiving sensitivity of transducer to front waves becomes equal to that of back waves when backing layer 12 is compressed and, in extreme cases, back wave sensitivity becomes greater than front wave sensitivity. Further, distortion of backing layer 12 is propagated to other materials. In the result, waterproof molding material 16 is cracked, waterproof structure of transducer being destroyed. Forthese reasons, prior art ultrasonic transducer should not be used beyond the sea depth range 100 to 200 meters. The foregoing description holds good both ultrasonic receiver and transmitter, as they are reversible.
Summary ofthe invention
It is an object of the invention to improve the hydrostatic pressuretightness of ultrasonic transducer.
It is another object of the invention to improve the front to back ratio of ultrasonic transducer.
It is further object of the invention to improve mechanical strength of ultrasonic transducer.
To achieve the objects, ultrasonic transducer according to the present invention is characterized in that it comprises backing layers at the back of ultrasonic vibrator, the backing layers being composed of rubber material and metal plate and their thickness are restricted in the range from 1/9 to 14/36 of sound wave length respectively.
These and other objects of the invention will become more readily apparent from the ensuing specification when taken with the drawings.
Brief description of the drawings
Figure lisa cross-sectional view showing prior art ultrasonic transducer.
Figure 2 shows, in cross section, ultrasonic transducer according to one embodiment of the present invention.
Figure 3 is a diagram for clarifying the function of backing layers.
Figure 4 is a graph showing a relationship of the front to back ratio to the frequency of sound waves.
Figure 5 is a cross-sectionai view showing another embodiment of the present invention in which ultrasonic vibrator array is provided.
Figure 6 shows, in cross section, further embodiment of the present invention in which dicing-type vibrator is provided.
Detailed description ofpreferred embodiments
Referring now to Figure 2, numeral 18 indicates ultrasonic vibrator made of barium titanate or zirconium lead titanate of longitudinal or lateral oscillation mode, numeral 20 indicates rubber material of neoprene or urethane, numeral 22 indicates metal plate of stainless steel, iron or copper, numeral 24 indicates cable and numeral 26 indicates waterproof molding material. Backing layers of ultrasonic transducer are provided which comprise rubber material 20 and metal plate 22 at the back of plate-like ultrasonic vibrator 18 and the thickness of rubber material 20 and metal plate 22 are restricted in the range from 1/9 to 14/36 of sound wave length B.
Referring to Figures 2 to 4, ultrasonic vibrator 18 oscillates to generate corresponding electric voltages in cable 24 when ultrasonic sound waves arrive in front of ultrasonic transducer as shown by an arrow A.
Assuming that sound waves arrive from the back of ultrasonic transducer, however, sound wave W1 which has been reflected by a boundary N between molding material 26 and backing layers in Figure 3 and sound wave W2 which has passed through the boundary N and has been reflected by another boundary M between metal plate 24 and rubber material 20 are composed and strengthened when the thickness of metal plate 22 is 1/4k as is understood by wave mechanics. On the contrary, sound wave W3 which has passed through boundaries N and M and has been reflected by boundary L between rubber material 20 and ultrasonic vibrator 18 and further reflected by boundary M and sound wave W4 which has passed through boundaries
N and M to reach at boundary Attenuate each other.In summary, oscillation caused by back waves can be weakened by restricting the thickness of rubber material 20 and metal plate 22 1/4 X (sound wave length) respectively, thereby improving front to back ratio and directivity of transducer.
Above descriptions are only qualitative and, in practice, reflection and transmission are in multiplex mode.
Ensuing descriptions are outline of calculation by the inventor in consequence to transmission characteristic analysis. FBR (front to back ratio) is equal to transmission coefficient by back waves on condition that the following formula can be represented.
where ZO: acoustic impedance of ultrasonic vibrator 18, Rw: acoustic impedance of sound field medium such as sea water,
Zb: acoustic impedance of backing material, Ko: number of waves of ultrasonic vibrator 18, LO: thickness of ultrasonic vibrator 18.
In the embodiment shown in Figure 2 provided a plurality of backing layers comprising rubber material 20 and metal plate 22, the thickness of those being 1 /4A (on the basis of frequency f0 of underwater sound waves). Assuming that metal plate is made of stainless steel, then open transmission coefficient, in other word FBR, can be represented as follows.
where Q=tanss -)
2 fo f: frequency.
Referring now to Figure 4, FBR of ultrasonic transducer is represented in relation to the frequency. The abscissa is calibrated to show f/fO and ordinate is calibrated to show FBR. It can well be understood from the figure that FBR of transducer is more than 20 dB when f/fO ranges 4/9 to 14/9. The range 4/9 to 14/9 of f/fO corresponds to, in wave length representation, 1/9 to 14/36h.
As is described in detail, a plurality of backing layers of rubber material and metal plate are provided at the back of ultrasonic vibrator according to the embodiment and the thickness of the layers are restricted in the range from 1/9 to 14/36k respectively. Thereby, FBR of the transducer can be kept more than 20 dB even at a depth of 1,500 meters in sea water. In addition, a plurality of backing layers of rubber material whose
Young's modulus is approximately equal to that of sound field medium, in other word sea water, and metal plate whose Young's modulus is by far the greater are provided. So, attenuation effect can be preserved even when the transducer suffers hydrostatic pressure in deep sea water. Moreover, waterproof molding material is not cracked due to distortion. Further, the vibrator must be shaped thinner in megaherz band.
Even in such case, the vibrator according to the invention is reinforced by a plurality of backing layers to improve mechanical strength. A single vibrator is provided in above-said embodiment. But, the present invention is also applicable, as shown in Figure 5, in case that ultrasonic vibrator array 28, in other word a number of vibrators, are provided. In addition, dicing-type vibrator 30 with a number of cuts in Figure 6 may be used. FBR can further be improved by providing a plurality of backing layers of rubber material and metal plate.
Obviously, many modifications and variations of the present invention are possible in the light of the above teachnings and it is therefore understood that within the scope of the invention the inventive concept may be practiced otherwise than specifically described.
Claims (5)
1. In ultrasonic transducer by which sound waves in the water are converted into electric signals in a reversible manner by ultrasonic vibrator, an invention comprising; backing layers at the back of said ultrasonic vibrator, the backing layers being composed of rubber material and metal plate and their thickness are restricted in the range from 1/9 to 14/36 of said sound wave length respectively.
2. An invention according to claim 1, wherein a plurality of backing layers are provided.
3. An invention according to claim 1 or 2, wherein said ultrasonic vibrator is composed of ultrasonic vibrator array.
4. An invention according to claim 1 or 2, wherein said ultrasonic vibrator is composed of dicing-type vibrator.
5. An ultrasonic transducer substantially as hereinbefore described with reference to any one of Figures 2,5 and 6 of the accompanying drawings.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12312279A JPS5920234B2 (en) | 1979-09-27 | 1979-09-27 | Ultrasonic transducer |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB2063007A true GB2063007A (en) | 1981-05-28 |
Family
ID=14852723
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8028490A Withdrawn GB2063007A (en) | 1979-09-27 | 1980-09-03 | Ultrasonic transducer |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JPS5920234B2 (en) |
| AU (1) | AU539636B2 (en) |
| FR (1) | FR2469852A1 (en) |
| GB (1) | GB2063007A (en) |
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0116823A1 (en) * | 1983-01-20 | 1984-08-29 | Siemens Aktiengesellschaft | Ultrasonic transducer |
| DE3437862A1 (en) * | 1983-10-17 | 1985-05-23 | Hitachi Medical Corp., Tokio/Tokyo | ULTRASONIC TRANSDUCER AND METHOD FOR THE PRODUCTION THEREOF |
| US4679179A (en) * | 1982-06-15 | 1987-07-07 | Raychem Corporation | Sonar detection apparatus |
| US4759000A (en) * | 1985-06-13 | 1988-07-19 | Reitz Ronald P | Acoustic energy absorbing material |
| WO1989011251A1 (en) * | 1988-05-27 | 1989-11-30 | Hoffmann Medizinische Technik Gmbh | Process for generating shock waves and shock wave generator for implementing said process |
| EP0366161A2 (en) * | 1982-12-30 | 1990-05-02 | Fujitsu Limited | Electro-sound transducer, and a probe unit or ultrasonic diagnostic apparatus using such a transducer |
| EP0375498A1 (en) * | 1988-12-20 | 1990-06-27 | Thomson-Csf | Directional linear modular hydrophonic antenna |
| US4982385A (en) * | 1989-11-17 | 1991-01-01 | Westinghouse Electric Corp. | Acoustic decoupler for a sonar array |
| US5436874A (en) * | 1993-11-17 | 1995-07-25 | Martin Marietta Corporation | Method and apparatus for sensing acoustic signals in a liquid |
| US8570837B2 (en) * | 2007-12-06 | 2013-10-29 | Measurement Specialties, Inc. | Multilayer backing absorber for ultrasonic transducer |
| CN106037803A (en) * | 2016-06-27 | 2016-10-26 | 中国科学院苏州生物医学工程技术研究所 | Ultrasonic transducer array, ultrasonic intervention treatment system and ultrasonic ablation catheter |
| EP4335558A1 (en) * | 2022-09-08 | 2024-03-13 | Nederlandse Organisatie voor toegepast-natuurwetenschappelijk Onderzoek TNO | Acoustic device and method of manufacturing |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58191788U (en) * | 1982-06-14 | 1983-12-20 | 古野電気株式会社 | Ultrasonic transducer for underwater detection |
| US4754440A (en) * | 1985-12-27 | 1988-06-28 | Aisin Seiki Kabushikikaisha | Ultrasonic transducer |
| CN104226576A (en) * | 2013-06-18 | 2014-12-24 | 柯宜京 | Back lining structural system for thickness mode vibration ultrasonic transducer |
| CN105015415A (en) * | 2015-07-29 | 2015-11-04 | 奇瑞汽车股份有限公司 | Anti-collision braking system for automobile parking |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2434143A (en) * | 1943-04-17 | 1948-01-06 | Chilowsky Constantin | Supersonic signal transmitter and receiver |
| US3480906A (en) * | 1968-03-13 | 1969-11-25 | Westinghouse Electric Corp | Transducer having a backing mass spaced a quarter wavelength therefrom |
| US3601789A (en) * | 1969-10-08 | 1971-08-24 | Us Navy | Deep-submergence acoustic array stave |
| JPS5318893B2 (en) * | 1971-12-03 | 1978-06-17 | ||
| US3854060A (en) * | 1973-10-12 | 1974-12-10 | Us Navy | Transducer for fm sonar application |
| US3995179A (en) * | 1974-12-30 | 1976-11-30 | Texaco Inc. | Damping structure for ultrasonic piezoelectric transducer |
-
1979
- 1979-09-27 JP JP12312279A patent/JPS5920234B2/en not_active Expired
-
1980
- 1980-08-27 FR FR8018569A patent/FR2469852A1/en active Granted
- 1980-08-27 AU AU61780/80A patent/AU539636B2/en not_active Expired
- 1980-09-03 GB GB8028490A patent/GB2063007A/en not_active Withdrawn
Cited By (17)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4679179A (en) * | 1982-06-15 | 1987-07-07 | Raychem Corporation | Sonar detection apparatus |
| EP0366161A2 (en) * | 1982-12-30 | 1990-05-02 | Fujitsu Limited | Electro-sound transducer, and a probe unit or ultrasonic diagnostic apparatus using such a transducer |
| EP0366161A3 (en) * | 1982-12-30 | 1990-07-11 | Fujitsu Limited | Electro-sound transducer, and a probe unit or ultrasonic diagnostic apparatus using such a transducer |
| EP0116823A1 (en) * | 1983-01-20 | 1984-08-29 | Siemens Aktiengesellschaft | Ultrasonic transducer |
| DE3437862A1 (en) * | 1983-10-17 | 1985-05-23 | Hitachi Medical Corp., Tokio/Tokyo | ULTRASONIC TRANSDUCER AND METHOD FOR THE PRODUCTION THEREOF |
| US4759000A (en) * | 1985-06-13 | 1988-07-19 | Reitz Ronald P | Acoustic energy absorbing material |
| WO1989011251A1 (en) * | 1988-05-27 | 1989-11-30 | Hoffmann Medizinische Technik Gmbh | Process for generating shock waves and shock wave generator for implementing said process |
| EP0375498A1 (en) * | 1988-12-20 | 1990-06-27 | Thomson-Csf | Directional linear modular hydrophonic antenna |
| US4982385A (en) * | 1989-11-17 | 1991-01-01 | Westinghouse Electric Corp. | Acoustic decoupler for a sonar array |
| US5436874A (en) * | 1993-11-17 | 1995-07-25 | Martin Marietta Corporation | Method and apparatus for sensing acoustic signals in a liquid |
| US8570837B2 (en) * | 2007-12-06 | 2013-10-29 | Measurement Specialties, Inc. | Multilayer backing absorber for ultrasonic transducer |
| US9713825B2 (en) | 2007-12-06 | 2017-07-25 | Measurement Specialties, Inc. | Multilayer backing absorber for ultrasonic transducer |
| US10486197B2 (en) | 2007-12-06 | 2019-11-26 | Measurement Specialites Inc. | Multilayer backing absorber for ultrasonic transducer |
| CN106037803A (en) * | 2016-06-27 | 2016-10-26 | 中国科学院苏州生物医学工程技术研究所 | Ultrasonic transducer array, ultrasonic intervention treatment system and ultrasonic ablation catheter |
| CN106037803B (en) * | 2016-06-27 | 2023-09-01 | 中国科学院苏州生物医学工程技术研究所 | Ultrasonic transducer array, ultrasonic interventional therapy system and ultrasonic ablation catheter |
| EP4335558A1 (en) * | 2022-09-08 | 2024-03-13 | Nederlandse Organisatie voor toegepast-natuurwetenschappelijk Onderzoek TNO | Acoustic device and method of manufacturing |
| WO2024054112A1 (en) * | 2022-09-08 | 2024-03-14 | Nederlandse Organisatie Voor Toegepast-Natuurwetenschappelijk Onderzoek Tno | Acoustic device and method of manufacturing |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5647196A (en) | 1981-04-28 |
| AU6178080A (en) | 1981-03-12 |
| FR2469852A1 (en) | 1981-05-22 |
| FR2469852B1 (en) | 1985-03-01 |
| JPS5920234B2 (en) | 1984-05-11 |
| AU539636B2 (en) | 1984-10-11 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |