EP1169143A1 - Impuls-ultraschallwandler mit einem elementarblock aus piezoelektischem material - Google Patents
Impuls-ultraschallwandler mit einem elementarblock aus piezoelektischem materialInfo
- Publication number
- EP1169143A1 EP1169143A1 EP00929375A EP00929375A EP1169143A1 EP 1169143 A1 EP1169143 A1 EP 1169143A1 EP 00929375 A EP00929375 A EP 00929375A EP 00929375 A EP00929375 A EP 00929375A EP 1169143 A1 EP1169143 A1 EP 1169143A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- block
- sound transducer
- piezoelectric material
- impulse sound
- collar
- 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.)
- Granted
Links
- 239000000463 material Substances 0.000 title claims abstract description 9
- 230000010287 polarization Effects 0.000 claims description 8
- 238000007493 shaping process Methods 0.000 claims 1
- 238000005516 engineering process Methods 0.000 abstract description 3
- 238000013016 damping Methods 0.000 description 6
- 230000005684 electric field Effects 0.000 description 6
- 238000004519 manufacturing process Methods 0.000 description 5
- 230000000694 effects Effects 0.000 description 4
- 238000010276 construction Methods 0.000 description 3
- 230000035945 sensitivity Effects 0.000 description 3
- 230000010355 oscillation Effects 0.000 description 2
- 238000002604 ultrasonography Methods 0.000 description 2
- 208000023514 Barrett esophagus Diseases 0.000 description 1
- 240000006829 Ficus sundaica Species 0.000 description 1
- 241000405217 Viola <butterfly> Species 0.000 description 1
- 230000006978 adaptation Effects 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 230000002238 attenuated effect Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 230000005284 excitation Effects 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000009659 non-destructive testing Methods 0.000 description 1
- 239000011295 pitch Substances 0.000 description 1
- 230000001902 propagating effect Effects 0.000 description 1
Classifications
-
- 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
Definitions
- the invention relates to a pulse transducer in the ultrasonic range. Such converters are needed in many areas of technology where short pulses are necessary. Defectoscopy comes first, followed by sonography in the medical field.
- the classic design of such a transducer consists of a plane-parallel plate made of piezoelectric material, which has electrodes on the two flat upper and lower sides, the plate being polarized perpendicular to the sides covered with electrodes.
- This plate is glued to a block that dampens the ultrasonic wave and has acoustic impedance that is matched to the piezo plate.
- So-called adaptation layers are provided on the outlet side, which allow reflection-free sound transmission and very short pulses to be achieved in pulse mode. Converters of this type are well known State of the art, and a good discussion of it and the problems that arise, can be found, for example, in the book by MG Silk, Ultrasonic Transducers for Nondestructive Testing, Adam Hüger 1984.
- Converters of the well-known type require a complex and therefore expensive technology if they are to generate really good impulses. Furthermore, the known transducers are relatively thick (at least 5 mm) and it is virtually impossible to manufacture them for frequencies that are greater than 30 MHz. Also, with pulse excitation, only relatively long pulses are generated, which have a negative effect on the measurements. Another disadvantage is that they are not suitable for automatic mass production and their parameters cannot be kept within a narrow tolerance range.
- Transducers with lens-shaped elementary blocks have relatively good pulse shapes and also good repeatability, but they only produce weak signals and are considerably less sensitive compared to classic converters. The same disadvantages have also been found in transducers which are able to deliver relatively short signals due to the special electrode design or inhomogeneous polarization of the piezo element.
- the object on which the invention is based is to create a sound transducer for the ultrasound range which emits strong and short pulses, has a high sensitivity and ensures repeatability of the parameters in series production.
- the object is achieved according to the invention by the features of the pulse sound transducer contained in the characterizing part of claim 1.
- the block which is T-shaped in longitudinal section and which may have a column, cone or pyramid shape with a round, oval or polygonal cross section is dimensioned in such a way that that there is damping of the shaft which moves inside the column to prevent it from reflecting on the free column wall and emerging as a ringing which deteriorates the pulse quality. It is therefore possible to dispense with further damping means. In addition, the production as a mass article is made considerably easier by the omission of additional damping means and adhesive connections. It is essential for the invention to form a collar on the block to form the unit cell. This shape, the selected proportions and the arrangement of the electrodes, which are arranged on the exit surface and around the block above the collar, are decisive for the basic vibration, which is designed in three dimensions.
- the basic polarization direction of the piezo material should run perpendicular to the base surface, that is to say the exit surface of the pulse of the T-shaped unit cell.
- Fig. 3 shows the electric field within the elementary cell.
- Figure 1 shows the unit cell 1 in a perspective view. This consists of block 2 and the collar 3 molded onto it. The collar protrudes over the block.
- the unit cell 1 is triangular in section, but it can also have any other shape. It can be round, oval and polygonal, and taper to the top as a cone or pyramid.
- One electrode 4 is arranged on the straight exit surface of the pulse, while the other electrode 5 extends laterally along the block 2. It is not necessary for the electrode 5 to run around the entire block, nor for the lower electrode to cover the entire lower surface.
- the thickness of the covenant is marked with a, the height of the block with b, the width of the block with c and the total height of unit cell 1 with h.
- the active area of the unit cell is located in the lower part of the block and within the federal government.
- the proportions of the unit cell are essential. It has been shown that the thickness of the collar in relation to the height of the block of piezoelectric material to the total height, So keep a / b / h in the ratio 1/4 - 6/10 in order to produce optimal results. Optimal results means that strong and short impulses are emitted and the converter has a high sensitivity. 2 shows the pulse curve achieved with the sound transducer according to the invention.
- the T-shape of the elementary cell 1 according to the invention is of very great importance since it enables the electric field between the electrodes within the elementary cell to be closed.
- 3 shows the image of the electric field in the unit cell. As can be seen from this, this only runs within the unit cell of the converter. This shape also enables volume oscillation and all upwards s.
- Fig. 1 directed waves, that is, against the impulse exit surface propagating waves so attenuated that they can no longer be reflected at the upper end of the unit cell.
- the proportions of the unit cell are of great importance.
- the ratio of the individual parts of the unit cell has already been specified.
- the height of cell h should be at least 10 times greater than the height of collar a.
- Such a converter produces pulses that are 20 ns long and has a bandwidth of 4 - 35 MHz as a receiver.
- the ultrasonic wave that goes up in the drawing is totally damped.
- the complete transducer does not have to be thicker than 2 mm. It is even possible to make it significantly thinner if the unit cell is constructed in such a way that it forms a peak at the top, which prematurely dampens the wave going in this direction.
- the component of the electric field that is parallel to the foot of the unit cell 1, that is to say the transverse bars of the T, is comparable to the component perpendicular to it.
- the properties of the transducer according to the invention are only determined by the properties of the selected piezoelectric material and the precision of the shape of the unit cell, i. H. in other words, the converter according to the invention can be produced with very good repeatability.
- Transducers of this type can contain one or more unit cells that can be connected to one another.
- the converter according to the invention is able to produce very short and very strong pulses that cannot be achieved with other converter designs.
- the amplitude of the pulses produced is at least twice greater than that of the classic converters. Its sensitivity is comparable to that of classic designs.
- the converter according to the invention can, however, be manufactured at considerably lower costs and used wherever classic converter types can also be used.
- the converter according to the invention can achieve a significant increase in effectiveness in comparison to other non-classical constructions, since no losses of the electric field occur to the outside and all undesired sound waves are subjected to an almost complete damping without this large ceramic thickness or other damping bodies would have to be used.
- the pulse length is shorter and the amplitude larger. None of the known designs is easier to manufacture.
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Transducers For Ultrasonic Waves (AREA)
- Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)
- Piezo-Electric Transducers For Audible Bands (AREA)
- Surgical Instruments (AREA)
Description
Claims
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE19917429A DE19917429A1 (de) | 1999-04-19 | 1999-04-19 | Impulsschallwandler |
DE19917429 | 1999-04-19 | ||
PCT/EP2000/003489 WO2000062946A1 (de) | 1999-04-19 | 2000-04-18 | Impuls-ultraschallwandler mit einem elementarblock aus piezoelektrischem material |
Publications (2)
Publication Number | Publication Date |
---|---|
EP1169143A1 true EP1169143A1 (de) | 2002-01-09 |
EP1169143B1 EP1169143B1 (de) | 2004-12-22 |
Family
ID=7904937
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP00929375A Expired - Lifetime EP1169143B1 (de) | 1999-04-19 | 2000-04-18 | Impuls-ultraschallwandler mit einem elementarblock aus piezoelektischem material |
Country Status (7)
Country | Link |
---|---|
US (1) | US6720715B1 (de) |
EP (1) | EP1169143B1 (de) |
AT (1) | ATE285302T1 (de) |
CA (1) | CA2366956A1 (de) |
DE (2) | DE19917429A1 (de) |
PL (1) | PL351622A1 (de) |
WO (1) | WO2000062946A1 (de) |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR100927493B1 (ko) * | 2001-11-02 | 2009-11-17 | 프로덕트 시스템즈 인코포레이티드 | 방사출력 메가소닉 변환기 |
US6984922B1 (en) * | 2002-07-22 | 2006-01-10 | Matsushita Electric Industrial Co., Ltd. | Composite piezoelectric transducer and method of fabricating the same |
JP4473532B2 (ja) * | 2002-10-10 | 2010-06-02 | 日本碍子株式会社 | 圧電/電歪デバイス及び製造方法 |
Family Cites Families (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3271704A (en) * | 1963-03-25 | 1966-09-06 | Bell Telephone Labor Inc | Ultrasonic delay device |
DE2314420C3 (de) * | 1973-03-22 | 1978-03-30 | Siemens Ag, 1000 Berlin Und 8000 Muenchen | Piezoelektrische Taste |
US3891869A (en) * | 1973-09-04 | 1975-06-24 | Scarpa Lab Inc | Piezoelectrically driven ultrasonic generator |
SE455538B (sv) * | 1985-12-06 | 1988-07-18 | Tekniska Roentgencentralen Ab | Ultraljudssond for provning av ett slitsat eller halforsett materialstycke |
GB2225426B (en) * | 1988-09-29 | 1993-05-26 | Michael John Gill | A transducer |
WO1997016260A1 (de) * | 1995-11-02 | 1997-05-09 | Sonident Anstalt | Piezoelektrischer ultraschallwandler |
US5606297A (en) * | 1996-01-16 | 1997-02-25 | Novax Industries Corporation | Conical ultrasound waveguide |
US6777856B2 (en) * | 2001-08-02 | 2004-08-17 | Kistler Holding Ag | Crystal element for piezo sensors |
-
1999
- 1999-04-19 DE DE19917429A patent/DE19917429A1/de not_active Withdrawn
-
2000
- 2000-04-18 CA CA002366956A patent/CA2366956A1/en not_active Abandoned
- 2000-04-18 US US10/070,351 patent/US6720715B1/en not_active Expired - Fee Related
- 2000-04-18 WO PCT/EP2000/003489 patent/WO2000062946A1/de active IP Right Grant
- 2000-04-18 PL PL00351622A patent/PL351622A1/xx unknown
- 2000-04-18 AT AT00929375T patent/ATE285302T1/de not_active IP Right Cessation
- 2000-04-18 EP EP00929375A patent/EP1169143B1/de not_active Expired - Lifetime
- 2000-04-18 DE DE50009032T patent/DE50009032D1/de not_active Expired - Fee Related
Non-Patent Citations (1)
Title |
---|
See references of WO0062946A1 * |
Also Published As
Publication number | Publication date |
---|---|
CA2366956A1 (en) | 2000-10-26 |
DE19917429A1 (de) | 2000-10-26 |
DE50009032D1 (de) | 2005-01-27 |
EP1169143B1 (de) | 2004-12-22 |
US6720715B1 (en) | 2004-04-13 |
WO2000062946A1 (de) | 2000-10-26 |
ATE285302T1 (de) | 2005-01-15 |
PL351622A1 (en) | 2003-05-19 |
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