WO1991012093A1 - Procede et appareil pour generer une onde ultrasonore - Google Patents
Procede et appareil pour generer une onde ultrasonore Download PDFInfo
- Publication number
- WO1991012093A1 WO1991012093A1 PCT/FR1991/000105 FR9100105W WO9112093A1 WO 1991012093 A1 WO1991012093 A1 WO 1991012093A1 FR 9100105 W FR9100105 W FR 9100105W WO 9112093 A1 WO9112093 A1 WO 9112093A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- transducer
- medium
- ultrasound
- ultrasonic wave
- thick
- Prior art date
Links
- 238000000034 method Methods 0.000 title claims abstract description 12
- 238000002592 echocardiography Methods 0.000 claims abstract description 5
- 238000002604 ultrasonography Methods 0.000 claims description 33
- 239000002033 PVDF binder Substances 0.000 claims description 5
- 229920002981 polyvinylidene fluoride Polymers 0.000 claims description 5
- 230000005284 excitation Effects 0.000 claims description 4
- 238000010586 diagram Methods 0.000 description 6
- 238000003384 imaging method Methods 0.000 description 4
- 230000010355 oscillation Effects 0.000 description 4
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 3
- 239000000463 material Substances 0.000 description 2
- 230000035945 sensitivity Effects 0.000 description 2
- 229920002554 vinyl polymer Polymers 0.000 description 2
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- 229910021523 barium zirconate Inorganic materials 0.000 description 1
- DQBAOWPVHRWLJC-UHFFFAOYSA-N barium(2+);dioxido(oxo)zirconium Chemical compound [Ba+2].[O-][Zr]([O-])=O DQBAOWPVHRWLJC-UHFFFAOYSA-N 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 239000011651 chromium Substances 0.000 description 1
- 230000003292 diminished effect Effects 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 239000002985 plastic film Substances 0.000 description 1
- 229920006255 plastic film Polymers 0.000 description 1
- 238000007747 plating Methods 0.000 description 1
- 238000005498 polishing Methods 0.000 description 1
- 239000010453 quartz Substances 0.000 description 1
- 230000001739 rebound effect Effects 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 238000004381 surface treatment Methods 0.000 description 1
- 238000012285 ultrasound imaging Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/22—Details, e.g. general constructional or apparatus details
- G01N29/24—Probes
-
- 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
- B06B1/0651—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 of circular shape
-
- 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
- G10K11/18—Methods or devices for transmitting, conducting or directing sound
- G10K11/26—Sound-focusing or directing, e.g. scanning
- G10K11/32—Sound-focusing or directing, e.g. scanning characterised by the shape of the source
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2291/00—Indexing codes associated with group G01N29/00
- G01N2291/04—Wave modes and trajectories
- G01N2291/042—Wave modes
- G01N2291/0423—Surface waves, e.g. Rayleigh waves, Love waves
Definitions
- the invention relates to a method for generating an ultrasonic wave for use in ultrasound, with obtaining good resolution.
- the invention relates more particularly, but not exclusively, to ultrasound ultrasound used in dermatological research, in particular for carrying out imaging of the skin.
- the invention can be applied to ultrasound in general, for example for the study of surface treatments, such as chromium plating.
- ultrasound ultrasound requires the use of transducers operating at high frequencies of at least 20 MHz.
- the pulse generated has oscillations or twists, as illustrated in FIG. 1 of the appended drawings, which impair longitudinal and lateral resolution.
- the object of the invention is, above all, to provide a method which makes it possible to generate a wave, preferably unipolar, the diagram of which is given in FIG. 2 of the appended drawing, with a view to its use in ultrasound.
- the method according to the invention for generating an ultrasonic wave, for use in ultrasound, provides for using a thick transducer whose face, facing towards the medium where the ultrasound is sent, is a concave curved surface to allow focusing the ultrasonic wave in the medium to be studied and obtaining good lateral resolution.
- the method makes it possible to generate a unipolar ultrasonic wave, the means of electrical excitation of the transducer being suitable for applying a voltage step, on this transducer, to produce a pressure pulse.
- thick transducer we mean a transducer for which the time taken by an ultrasonic pulse to travel the thickness of the transducer from one face to the other is clearly greater than the duration of the pulse, in particular at least five times bigger.
- a transducer which then plays the role of receiver, or a sensor, which can be of a different nature, placed between the transmitting transducer and the medium or object to be analyzed.
- the invention also relates to an apparatus for generating an ultrasonic wave for use in ultrasound, comprising a transducer and means for electrically exciting this transducer, this apparatus being characterized in that, to produce a wave: - the transducer is thick;
- the face of the thick transducer, facing towards the medium where the ultrasound is transmitted, is limited by a concave curved surface allowing a focusing of the ultrasonic wave.
- the device produces a unipolar ultrasonic wave, the electric excitation means being suitable for applying a voltage step to the transducer.
- the concave face of the transducer can be formed by a spherical cap.
- the apparatus includes a receiver which can use the thick emission transducer; in this case, electronic means are provided to derive the received signal in order to recover the image of the pressure pulse.
- the receiver comprises a piezoelectric sensor disposed between the transmitting transducer and the medium or object to be analyzed.
- This piezoelectric sensor can be a
- PVDF polyvinyl difluoride
- a PVDF film can be either glued to the transmitter or placed at a distance from the transmitter.
- the invention consists, apart from the arrangements set out above, of a certain number of other arrangements which will be more explicitly discussed below in connection with an exemplary embodiment described with reference to the attached drawing, but which is by no means limiting.
- FIG. 1 of this drawing is a diagram of an ultrasound transmitter of the prior art and of the oscillating wave produced by this transmitter, the time being plotted on the abscissa, and the amplitude on the ordinate.
- FIG. 2 is a diagram of a unipolar wave, time being. plotted on the abscissa, and the amplitude on the ordinate.
- FIG. 3 is a diagram illustrating the response of a thick transducer excited by a pulse.
- Figure 4 is a diagram of bipolar pulses.
- FIG. 5 is a diagram of an apparatus according to the invention.
- FIG. 6 represents a relatively rapid descent voltage step.
- FIG. 7 represents the unipolar wave obtained from the excitation of the thick transducer by the signal of FIG. 6.
- FIG. 8 represents a voltage step with relatively slow descent.
- the ultrasonic transducers 1 (FIG. 1) used in the field of ultrasound have been relatively thin, that is to say that their thickness e was such that the travel time from one face to the other of this transducer 1 by an ultrasonic wave was equal to or close to half the wavelength.
- the axial resolution in the case of ultrasound ultrasound imaging, depends on the duration of the ultrasonic signal, that is to say on the width 1 of the signal 3. The axial resolution is improved if the width 1_ is diminished.
- the reduction in the width JL is obtained by the increase in the frequency of the ultrasonic waves, that is to say the reduction of the pseudo-period, which results in the reduction of the thickness e_ of the transducer 1.
- the invention instead of proposing to further reduce the thickness of the piezoelectric transducer, surprisingly proposes for ultrasound ultrasound to use a thick transducer 4 (FIG. 5) of thickness h whose front face 5, facing towards the middle M where the ultrasound is sent, is formed by a concave curved surface allowing a focusing of the ultrasonic wave at a point B.
- electrical means 6 are provided to excite the transducer ultrasonic 4, no longer by an electrical pulse such as pulse 2 in FIG. 1, but by a voltage step 7.
- a thick transducer 8 ( Figure 3), with flat, parallel end faces, excited by a pulse electric ion 2, alternately supplies a positive pressure pulse 9 and a negative pressure pulse 10.
- the solution of the invention which provides a concave front face 5 for the thick transducer 4, allows, by focusing the ultrasonic wave, to obtain a good lateral resolution which is added to the good axial resolution.
- Figure 6 shows a relatively fast downward voltage step to obtain the unipolar wave of Figure 7.
- Figure 8 shows a longer downward voltage step than in the case of Figure 6 leading to the wave unipolar of figure 9.
- the transducer is excited with a voltage signal which corresponds to the integral (or primitive) of the wave which it is desired to obtain at focus B.
- the transducer 4 is excited with a voltage step 7.
- the unipolar wave u. corresponds well to the derivative with respect to time of the voltage step electric 7.
- the thick transducer 5 was cylindrical with a diameter of 20 mm and a length of 25 mm, and was made of barium zirconate.
- the voltage step 7 corresponded to a voltage variation of 6000 volts in a time of 10 ns, which made it possible to obtain a resolution of 7.5 microns.
- the electrical voltage step corresponds to a pressure step on face 5 with a duration of 17 ns.
- the focal length was 25 mm.
- the quality of the transducer bore the reference PI 60 or PI 68, sold by the company Quartz and Silica.
- the unipolar wave u had a duration d equal to 50 ns.
- the focal spot had a diameter of about 20 microns.
- the concave surface 5 was a spherical surface, polished to the nearest micron (according to the methods used in optics for polishing the mirrors). Two possibilities of reception of ultrasonic echoes can be envisaged.
- a first possibility consists in using the same thick transducer 4 which then plays the role of receiver.
- a pressure pulse such that it arrives on the thick transducer 4 gives a voltage step.
- the electrical means 6 comprise an electronic differentiating circuit (6a) capable of deriving the echo signal received by the transducer 4 and of providing. on its output, the image-of the pressure pulse.
- deriving the received echo signal may cause interference.
- Another advantageous possibility for receiving echoes is to have a piezoelectric sensor 12 connected to electronic analysis means 13 between the emitting transducer 4 and the medium M to be analyzed.
- a PVDF polyvinyl difluoride
- the PVDF film can be bonded to all or part of the face 5 of the transmitter. As a variant, it can be placed at a distance from the transmitter 4.
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- Multimedia (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Mechanical Engineering (AREA)
- Acoustics & Sound (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Ultra Sonic Daignosis Equipment (AREA)
- Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)
Abstract
Description
Claims
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP91504965A JPH05505323A (ja) | 1990-02-14 | 1991-02-12 | 超音波を発生する方法及び装置 |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR9001737A FR2658298B1 (fr) | 1990-02-14 | 1990-02-14 | Procede et appareil pour generer une onde ultrasonore en vue de son utilisation en echographie avec obtention d'une bonne resolution. |
FR90/01737 | 1990-02-14 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1991012093A1 true WO1991012093A1 (fr) | 1991-08-22 |
Family
ID=9393696
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/FR1991/000105 WO1991012093A1 (fr) | 1990-02-14 | 1991-02-12 | Procede et appareil pour generer une onde ultrasonore |
Country Status (5)
Country | Link |
---|---|
EP (1) | EP0515557A1 (fr) |
JP (1) | JPH05505323A (fr) |
CA (1) | CA2075049A1 (fr) |
FR (1) | FR2658298B1 (fr) |
WO (1) | WO1991012093A1 (fr) |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5657391A (en) * | 1979-10-17 | 1981-05-19 | Fujitsu Ltd | Ultrasonic oscillator |
-
1990
- 1990-02-14 FR FR9001737A patent/FR2658298B1/fr not_active Expired - Fee Related
-
1991
- 1991-02-12 WO PCT/FR1991/000105 patent/WO1991012093A1/fr not_active Application Discontinuation
- 1991-02-12 EP EP19910905345 patent/EP0515557A1/fr not_active Withdrawn
- 1991-02-12 CA CA 2075049 patent/CA2075049A1/fr not_active Abandoned
- 1991-02-12 JP JP91504965A patent/JPH05505323A/ja active Pending
Non-Patent Citations (4)
Title |
---|
ANNALES DE DERMATOLOGIE ET DE VENEREOLOGIE, Vol. 116, Nos. 6-7, 1989, J.L. LEVEQUE et al., "L'echographie Ultrasonore en Recherche Dermatologique", pages 503-509. * |
JOURNAL OF ACOUSTICAL SOCIETY OF AMERICA, Vol. 41, No. 2, 1967, (New York, US), R.G. PETERSON et al., "Use of Thick Transducers to Generate Short-duration Stress Pulses in Thin Specimens", pages 336-345. * |
PATENT ABSTRACTS OF JAPAN, Vol. 5, No. 121, (E-68)[793], 5 August 1981; & JP,A,56 057 391 (FUJITSU K.K.), 19 May 1981. * |
ULTRASONICS, January- March 1965, (Guildford, GB), W. BUSCHMANN, "New Equipment and Transducers for Ophthalmic Diagnosis", pages 18-21. * |
Also Published As
Publication number | Publication date |
---|---|
EP0515557A1 (fr) | 1992-12-02 |
FR2658298A1 (fr) | 1991-08-16 |
JPH05505323A (ja) | 1993-08-12 |
FR2658298B1 (fr) | 1993-11-26 |
CA2075049A1 (fr) | 1991-08-15 |
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