EP0015886A1 - Elément transducteur électro-acoustique amélioré - Google Patents

Elément transducteur électro-acoustique amélioré Download PDF

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Publication number
EP0015886A1
EP0015886A1 EP80850028A EP80850028A EP0015886A1 EP 0015886 A1 EP0015886 A1 EP 0015886A1 EP 80850028 A EP80850028 A EP 80850028A EP 80850028 A EP80850028 A EP 80850028A EP 0015886 A1 EP0015886 A1 EP 0015886A1
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EP
European Patent Office
Prior art keywords
transducer element
piezoelectric film
additional layer
rear side
acoustic 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Withdrawn
Application number
EP80850028A
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German (de)
English (en)
Inventor
Hiroji Ohigashi
Toshiharu Nakanishi
Miyo Suzuki
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Toray Industries Inc
Original Assignee
Toray Industries Inc
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Priority claimed from JP2885079A external-priority patent/JPS5912079B2/ja
Priority claimed from JP3550479A external-priority patent/JPS5912240B2/ja
Application filed by Toray Industries Inc filed Critical Toray Industries Inc
Publication of EP0015886A1 publication Critical patent/EP0015886A1/fr
Withdrawn legal-status Critical Current

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R17/00—Piezoelectric transducers; Electrostrictive transducers
    • H04R17/005—Piezoelectric transducers; Electrostrictive transducers using a piezoelectric polymer
    • 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
    • G10K11/02—Mechanical acoustic impedances; Impedance matching, e.g. by horns; Acoustic resonators

Definitions

  • the acoustic impedance of the polymer piezoelectric material is by far lower than that of the inorganic piezoelectric material and very close to those of water, and general organic materials.
  • the polymer piezoelectric material functions as an excellent transmitter and receiver for ultrasonic waves which travel through these objects.
  • a potential of about 10 6 V/cm is needed for polarization of polymer for provision of piezoelectricity.
  • Polarization of a polymer film of a large thickness is often accompanied with troubles such as aerial discharge, thereby disabling easy preparation of a thick polymer piezoelectric film.
  • the available thickness under the present condition is 100 ⁇ m or smaller. This is the first disadvantage of the conventional art.
  • a polymer piezoelectric film is accompanied, on its acoustic emanation side, with an additional layer whose acoustic impedance (Z) is equal or very close to the acoustic impedance (Z o ) of the polymer piezoelectric film.
  • a polymer piezoelectric film is accompanied, on the side opposite to its acoustic emanation side, with an additional layer whose acoustic impedance (Z) is equal or very close to the acoustic impedance (Z o ) of the polymer piezoelectric film.
  • a polymer piezoelectric film is accompanied, on its both surface sides, with respective additional layers whose acoustic impedances are equal or very close to the acoustic impedance (Z o ) of the polymer piezoelectric film.
  • the additional layer may be either directly or indirectly disposed to the polymer piezoelectric film.
  • acoustic emanation side'' refers to one of the two surface sides of a polymer piezoelectric film which faces an acoustic transmission medium through which the ultrasonic waves of an aimed frequency travel away from or towards the polymer piezoelectric film.
  • this side of the film may be referred to "the front side” whereas the other side of the film opposite to this acoustic emanation side may be referred to "the rear side”.
  • the additional layer should be made of a material whose acoustic impedance (Z) is equal or very close to the acoustic impedance (Z o > of the piezoelectric film.
  • the ratio Z/Z o should be in a range from 0.2 to 2 exclusive. More preferably, the ratio Z/Z o should be in a range from 0.3 to 2 exclusively. Further preferably, the ratio Z/Z o should be in a range from 0.5 to 2 exclusive.
  • Such an additional layer is preferably made of a polymeric material such as polyethylene telephthalate, polycarbonate, PMMA, polystylene, ABS, polyethylene, polyvinyl chloride, polyamide, aromatic polyamide, polyvinylidene fluoride or a mixture of such a polymeric material with an inorganic compound.
  • a polymeric material such as polyethylene telephthalate, polycarbonate, PMMA, polystylene, ABS, polyethylene, polyvinyl chloride, polyamide, aromatic polyamide, polyvinylidene fluoride or a mixture of such a polymeric material with an inorganic compound.
  • a nylon, rubber, polyurethane or silicone rubber sheet is usable for the additional layer.
  • the material for the additional is first shaped into a film which is next bonded to the polymer piezoelectric film. It is also employable to coat one surface of the polymer piezoelectric film with the material for the additional layer.
  • diehlorobenzene solution of PMMA of chlorobenzene solution of polyethylene telephthalate is preferably used for the solvent, which may be removed by evaporation after coating.
  • the coating may be subjected to appropriate polymerization such as vapor phase polymerization.
  • h is equal to zero in the equation (1).
  • the two-port nextwork shown in Fig. 3 is -used for connecting the equivalent circuit in Fig. 2 to an electric power source having an internal,impedance Z S , the electric impedance of the transducer with respect to the power source being designated with Z L .
  • Fig. 4 The node of distribution and consumption of the energy supplied by the electric power source is schematically shown in Fig. 4, in which Pr is the reflection energy caused by inconsistency between Z S and Z in , P T is the input energy to the transducer and given in the form of the difference between P o and P r , P Af is the front acoustic emanation, P Ab is the rear acoustic emanation energy and P th is the internal consumption energy (heat) within the transducer, P th being equal to P T - (P Af + P Ab ). Hence, the following equations are conducted.
  • TLf should be designed as small as possible and TLb as large as possible over a wide frequency band, in order to enhance utility of a transducer used for non-destructive ultrasonic detection.
  • the transducer For measurement of the electric reflection loss ML, the transducer was placed within a water bath in which reflection of ultrasonic waves was negligible. The impedance of the transducer was measured by an arrangement shown in Fig. 6 in terms of the reflection voltage and its phase.
  • the transducer included a polyvinylidene fluoride film obtained by applying polarization for 1 hour at 10° v/cm and 120° C to an uniaxially drawn material film.
  • each transducer element includes a polymer piezoelectric film 11.
  • the bottom side of the polymer piezoelectric film 11 corresponds to the above-described acoustic emanation or front side.
  • the transducer element 10 shown in Fig. 7A includes a a polymer piezoelectric film 11, an electrode 14b fixed to the rear side surface of the film 11, another electrode 14a fixed to the front side surface of the film 11, and an additional layer 12 coupled to the film 11 via the front side electrode 14a.
  • the transducer element 10 shown in Fig. 7B includes a polymer piezoelectric layer 11, a rear side electrode 14b, an additional layer 12 fixed directly to the front side surface of the film 11, and a front side electrode 14a fixed to the front side surface of the additional layer 12.
  • the transducer element 10 shown in Fig. 70 includes a polymer piezoelectric film 11, a front side electrode 14a, an additional layer 12a coupled to the front side of the film 11 via the front side electrode 14a, a rear side electrode 14b, and another additional layer 12b coupled to the film 11 via the rear side electrode 14b.
  • the one additional layer 12a will hereinafter be referred to "a front side additional layer” and the other " a rear side additional layer”.
  • the transducer element 10 shown in Fig. 7D includes a polymer piezoelectric film 11, a front additional layer 12a coupled to the front side surface of the film 11 via a front side electrode 14a, and a rear side electrode 14b coupled to the rear side surface of the film 11 via a rear side additional layer 12b.
  • the transducer element 10 shown in Fig. 7E includes a polymer piezoelectric film 11, a front side electrode 14a coupled to the front side surface of the film 11 via a front side additional layer 12a, and a rear side additional layer 12b coupled to the rear side surface of the film via a rear side electrode 14b.
  • the transducer element 10 shown in Pig. 7F includes a polymer piezoelectric film 11, a front side electrode 14a coupled to the front side surface of the film 11 via a front side additional layer 12a, and a rear side electrode 14b coupled to the rear side surface of the film 11 via a rear side additional layer.12b.
  • One lead 28b extends outsides from the rear side electrode 24b whereas another lead 28a extends outsides from the front side electrode 24a via the conductive wafer 26.
  • the transducer 20 is placed in touch with an acoustic transmission medium ATM via the additional layer 22.
  • the reflector plate i.e. the rear side electrode 24b is made of a material whose acoustic impedance is by far larger than those of the polymer piezoelectric film 21 and the substrate 23. Metals such as Au, Cu and W are in general advantageously usable for this purpose.
  • an insulating material such as a PZT ceramic. plate may be added as a reflector plate.
  • transducer 20 shown in Fig. 8 incorporates the transducer element 10 shown in Fig. 7A, different type of transducer element 10 shown in either of Figs. 7B through 7F if usable for a similar purpose.
  • FIG. 23A through 23E Still further embodiments of the electro-acoustic transducer element in accordance with the present invention are shown in Figs. 23A through 23E.
  • the transducer element 30 shown in Fig. 23A includes a polymer piezoelectric film 31, a front side electrode 34a fixed to the front side surface of the film 31, and an additional layer 32 coupled to the rear side surface of the film 31 via a rear side electrode 34b.
  • the transducer element 30 shown in Fig. 23B includes a polymer piezoelectric film 31, a front side electrode 34a fixed to the front side surface of the film 31, and a rear side electrode 34b coupled to the rear side surface of the film 31 via an additional layer 32.
  • the transducer element 30 shown in Fig. 23C includes a polymer piezoelectric film 31, a front side electrode 34a fixed to the front side surface of the film 31, an additional layer 32 coupled to the rear side surface of the film 31 via a rear side electrode 34b, and an acoustic reflector plate 35 fixed to the rear side surface of the additional layer 32.
  • the transducer element 30 shown in Fig. 23D includes a polymer piezoelectric film 31, a front side electrode 34a fixed to the front side surface of the film 31, a rear side electrode 34b coupled to the rear side surface of the film 31 via an additional layer 32, and an acoustic reflector plate 35 fixed to the rear side surface of the rear side electrode 34b.
  • the transducer element 30 shown in Fig. 23 E includes a polymer piezoelectric film 31, a front side electrode 34a fixed to the front side surface of the film 31, an additional layer 32 coupled to the rear side surface of the film 31 via a rear side electrode 34b, and a substrate 33 fixed to the rear side surface of the additional layer 32.
  • Example 1 and comparative example 1.
  • a Fig. 7A-type transducer element 10 shown in Fig. 9A. was used in the measurement.
  • the polymer piezoelectric film 11 was made of polyvinylidene fluoride and 30 ⁇ m in thickness and 0.92 cm 2 in surface area. Water was used as the acoustic transmission medium ATM.
  • test pieces Four types were prepared.
  • the first to third test pieces I to IV included polyvinylidene fluoride, either piezoelectric or non-piezoelectric, additional layers, one for each, of 7.5,15, 30 and 60 ⁇ m thicknes respectively.
  • the fourth test piece IV included no additional layer.
  • a transducer element shown in Fig. 10A was prepared, which included a polyvinylidene fluoride piezoelectric film 11, front and rear side electrodes 14a and 14b, and a copper plate 15 of 66.5 ⁇ m thickness fixed to the front side surface of the front side electrode 14a. was used for the acoustic transmission medium ATM.
  • the piezoelectric film 11 was common in dimension to that used for the transducer element shown in Fig. 9A.
  • the loss presents minimal peaks at frequencies fo/2, fo and 3fo/2 but upsurges at other frequencies. That is, the transducer element of this type has narrow frequency-band filtering characteristics. In the evaluation of the relationship, the mechanical loss of the copper plate was disregarded.
  • resonant frequency of the transducer element in accordance with the present invention can be adjusted quite freely by means of appropriately changing the thickness of the front side additional layer 12 without any change in the thickness of the polymer piezoelectric film 11. This successfully precludes the above-described disadvantages inherent to the prior art.
  • FIG. 11 A different type of electro-acoustic transducer 40 in accordance with the present invention is shown in Fig. 11.
  • a Fig. 70-type transducer element is used.
  • the transducer 40 includes a metallic housing 45 having a bottom opening, a polymer piezoelectric film 41 placed in the housing 45 whilst closing the bottom opening, and a pair of electrodes 44a and 44b placed in contact with both side surfaces of the film 41.
  • a front side additional layer 42a is filled into the bottom opening and fixed to the housing 45 via an annular bond layer 47a.
  • a rear side additional layer 42b is located on the rear side electrode 44b and surrounded by an annular metallic ring 46.
  • a polyvinylidene fluoride film of 70 ⁇ m thickness and 4.4 cm 2 surface area was used for the piezoelectric film 41, polyester films of 25 and 50 ⁇ m thickness (t f ) were used for front side additional layer 42a, and polyester films of 25 and 50 ⁇ m thickness (t b ) were used for the rear side additional layer 42b.
  • a further transducer of like construction but without the rear side additional layer was prepared as a comparative example. Particulars of the test pieces are as follows.
  • FIG. 13 A further different type of electro-acoustic transducer 50 in accordance with the present invention is shown in Fig. 13.
  • a Fig. 7A-type transducer element is used.
  • the transducer 50 includes a hollow metallic housing 55, a cylinder 56 screwed to the bottom of the housing 55, and a polyvinylidene fluoride piezoelectric film 51 placed within the housing 55 whilst closing-the end opening of the cylinder 56.
  • the film 51 is backed by a PMMA substrate 53 via a rear side reflector plate 54b made of strainless steel.
  • the reflector plate 54b acts as a rear side electrode also, and 100 ⁇ m in thickness and 21.0 mm in diamter.
  • a front side additional layer 52 is coupled to the front side surface of the film 51 via a front side electrode 54a.
  • a lead 58 extends outwards- from the reflector plate 54b, i.e. the rear side electrode, and the metallic housing 55 is earthed.
  • the transducer 50 of the above-described construction was placed within a water bath for transmission of high frequency pulses of several ⁇ s periods and the ultrasonic waves reflected by a brass block immensed in the water bath were received by the same transducer.
  • the resultant actual frequency characteristics of its electro-acoustic conversion loss TL f are shown in Fig. 14 with nominal frequency characteristics theoretically estimated on the basis of the above-described equations (1) through (5).
  • the solid line curve is for the actual frequency characteristics and the dot line curve for the nominal frequency characteristics.
  • Fig. 15 For comparison, like frequency characteristics are shown in Fig. 15 for a comparative transducer without provision of the front side additional layer 52.
  • the solid line curve is for the actual values and the dot line curve for the estimated nominal values. Appreciable coincidence is recognized to exist between both values in this case also.
  • the difference in frequency characteristics between Figs. 14 and 15 is resulted from provision of the front side additional layer.
  • the resonant frequency for the minimum peak loss value is lowered from about 10 to 8 MHz without any substantial narrowing in the frequency band which the characteristic curve extends over.
  • test pieces were as follows;
  • Fig. 16 The nominal results obtained by estimation are shown in Fig. 16, in which the eleetro-acoustic conversion loss TL f and non-tuning conversion loss CLf are taken on the ordinate and the frequency of the ultrasonic wave used in the measurement is taken on the abscissa. It was confirmed that the difference in resonant frequency between the actual and nominal estimated values was 0.5 MHz and that in loss values was 3 dB or smaller. With increase in thickness of the additional layer 52, the resonant frequency shifted towards the lower side.
  • the relative frequency band ( ⁇ f/fr) was 0.52, 0.54, 0.57 and 0.63 for 0, 5, 25 and 50 ⁇ m thickness, respectively. That is, the relative frequency band increased with increase in thickness of the additional layer 52.
  • Fig. 17 depicts a still different type of transducer 60 incorporating a polymer piezoelectric transducer element in accordance with the present invention.
  • the transducer element used in this example is basically same in type with that used in Fig. 13 except that the entire construction is concave towards the acoustic emanation side, i.e. the front side.
  • the transducer 60 includes a polycarbonate pipe 65 of 20 mm outer diameter, a polyvinylidene fluoride piezoelectric film 61 of 76 ⁇ m thickness and bonded to the bottom opening of the pipe 65 and a pair of aluminium electrodes 64a and 64b disposed to both side surfaces of the film 61 by evaporation.
  • the front side electrode 64a is accompanied on its front side with a thin bronze phosphate ring 66 via electrically conductive bond.
  • An additional layer 62 made of undrawn polyvinylidene film is bonded to the ring 66 in contact with the front side electrode 64a.
  • a rearwardly converging copper substrate 63 of 13 mm maximum diameter is placed in the pipe 65 in contact with the rear side electrode 64b, which is in turn backed with an epoxy resin filler 67 in a manner such that the converging end of the substrate 63 projects rearwards.
  • a front side lead 68a extends outsides from the front side electrode 64a through the pipe whereas a rear side lead 68b extends from the converging end of the substrate 63.
  • the assembly is encased within a cylindical metallic housing 69.
  • test pieces I through V Five sets of different test pieces I through V were prepared as follows;
  • the estimated nominal frequency characteristics of the electro-acoustic conversion loss TL f are shown Fig. 18.
  • the resonant frequency shifts towards the lower side with increase in thickness of the additional layer 62.
  • Use of the additional layer enlarges the relative frequency band.
  • the electro-acoustic transducers prepared were able to generate sonic waves of frequencies well suited for diagnostic applications whilst using thin polymer piezoelectric films.
  • a brass plate was placed in the water bath measurement of echo signals reflected by the brass block. It was confirmed that there was a good coincidence between the actual and estimated nominal values.
  • a high frequency coil L of about 5 ⁇ H was connected in series to the transducer.
  • the transducer so prepared was used for obtaining resolution echogram of a fish in a water bath using an ultrasonic wave of 5MHz frequency. The resulting resolution was satisfactory for both depth and transverse direction.
  • the transducer 70 includes a polyvinylidene fluoride piezoelectric film 71 of 76 ⁇ m thickness and accompanied with a pair of aluminium electrodes 74a and 74b, an additional layer 72 coupled to the front side of the film 71 via a front side of the film 71 via a front side electrode 74a, a copper reflector plate 76 coupled to the rear side of the film 71, and a substrate 73.
  • the additional layer 72 is made of an uniaxially drawn polyvinylidene fluoride non-piezoelectric film.
  • the thickness of the reflector plate 76 is chosen so that it operates as a quarter wave-length plate in the vicinity of the resonant frequency.
  • test pieces I through V Five sets of test pieces I through V were prepared as follows;
  • Fig. 20 The frequency characteristics of the non-tuning conversion loss are shown in Fig. 20. It is noticed in the illustration that the lowest peak loss for the test piece IV (152 ⁇ m thickness) appears at 2.5 MHz frequency.
  • the piezoelectric film 71 is required to have a thickness of 230 ⁇ m, which is too large to produce easily. Further, this increased thickness causes lowering in electric capacity. In the case of the present invention, no lowering in capacity assures well match of the transducer to the electric power source.
  • the transducer 80' (test piece E) shown in Fig. 21B includes basically a Fig. 7A-type transducer element in accordance with the present invention, also. That is, the transducer 81' includes a polyvinylidene fluoride piezoelectric film 81' of 140 ⁇ m thickness, a polyethylene telephthalate additional layer 82' of 25 ⁇ m thickness and coupled to the front side of the film 81' via the front side electrode 84a, the copper reflector palte 86 fixed to the rear side surface of the film 81', and the bakelite substrate 83 backing the reflector plate 86.
  • the transducer 80" (test piece III) shown in Fig. 21C was prepared for comparison and conventional in construction.
  • the transducer 80" includes a polyvinylidene fluorize - piezoelectric film 81" of 76 ⁇ m thickness, the front side electrode 84a, a copper reflector plate 86" of 40 ⁇ m thickness, and a PMMA substrate 83" backing the reflector plate 86".
  • test piece I presents a further minimal loss peak at a double frequency approximately equal to 10MHz.
  • the system may be driven for operation by means of short pulse excitation also.
  • An electro-acoustic transducer incorporating a Fig. 23A-type transducer in accordance with the present invention was used with a water bath as the acoustic transmission medium ATM.
  • test pieces I to IV were as follows;
  • frequency characteristics of electric reflection loss ML f was measured also using the test piece II, the result being disignated in the graph with a chain line curve.
  • a transducer such as shown in Fig. 25 A was prepared, which includes a like polyvinylidene fluoride piezoelectric film accompanied with a front side electrode, and, as a substitute for the polyvinylidene fluoride backing additional layer, a copper plate of 163 ⁇ m. In this case, the copper plate acts as a rear side electrode also.
  • Frequency characteristics of electro-acoustic and electric reflection losses TL f and ML f were measured and are shown in Fig. 25B, respectively.
  • a water bath was used for the acoustic transmission medium ATM, also.
  • the minimal peak value for the electro-acoustic conversion loss TL f appears about the frequency of 7 MHz whereas, in Fig. 24, the test piece III has an almost similar resonant frequency for the electro-acoustic conversion loss TLf.
  • Fig. 24 further indicates that simple adjustment in thickness of the additional layer enable free choice of the resonant frequency.
  • Fig. 26A depicts an electro-acoustic transducer including a Fig. 23A-type transducer element in accordance with the present invention. That is, the transducer 90 includes a polyvinylidene piezoelectric film 91 of 76 ⁇ m thickness and 10 cm 2 surface area, a pair of electrodes 94a and 94b sandwiching the piezoelectric film 91, and a polyethylene telephthalate additional layer 92 in back of the rear side electrode 94b. The thickness of the additional layer is 25 ⁇ m for a test piece I and 100 ⁇ m for a test piece IL. The additional layer 92 is backed by a copper reflector plate 96 of 168 ⁇ m thickness, and further by a PMMA substrate 93. A water bath was used for the acoustic transmission medium ATM.
  • Fig. 26B Frequency characteristics of electro-acoustic conversion loss TL f were measured using the test pieces I and II and the obtained result is shown in Fig. 26B.
  • the transducer used in this Example is different from that shown in Fig. 25A (comparative example) in that an additional layer 92 is interposed between the polyvinylidene fluoride piezoelectric film 91 and the copper reflector plate 96. Due to insertion of the additional layer, the resonant frequency is lowered from about 7 MHz (Fig. 25B) to about 5 MHz (Fig. 26B). Thus, the effect caused by presence of the additional layer is clearly indicated.
  • An electro-acoustic transducer with low losses can be produced without any increase in thickness of the polyvinylidene fluoride piezoelectric film whose mechanical loss is rather on the higher side. Presence of the additional layer gives reliable projection to the polyvinylidene film against a wide variety of thinkable external attacks.
EP80850028A 1979-03-13 1980-03-12 Elément transducteur électro-acoustique amélioré Withdrawn EP0015886A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP2885079A JPS5912079B2 (ja) 1979-03-13 1979-03-13 超音波トランスデュ−サ
JP28850/79 1979-03-13
JP3550479A JPS5912240B2 (ja) 1979-03-28 1979-03-28 電気−音響変換素子
JP35504/79 1979-03-28

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EP0015886A1 true EP0015886A1 (fr) 1980-09-17

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EP (1) EP0015886A1 (fr)
AU (1) AU5637080A (fr)

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4383194A (en) * 1979-05-01 1983-05-10 Toray Industries, Inc. Electro-acoustic transducer element
FR2531298A1 (fr) * 1982-07-30 1984-02-03 Thomson Csf Transducteur du type demi-onde a element actif en polymere piezoelectrique
FR2551611A1 (fr) * 1983-08-31 1985-03-08 Labo Electronique Physique Nouvelle structure de transducteur ultrasonore et appareil d'examen de milieux par echographie ultrasonore comprenant une telle structure
US4549107A (en) * 1982-09-28 1985-10-22 Tokyo Shibaura Denki Kabushiki Kaisha Ultrasonic beam focusing device with a concave surface
EP0404154A2 (fr) * 1989-06-22 1990-12-27 Terumo Kabushiki Kaisha Sonde à ultrasons avec couche de matériaux à épaisseur irrégulière
WO2004007098A1 (fr) * 2002-07-15 2004-01-22 Eagle Ultrasound As Transducteurs ultrasonores a bande haute frequence et multifrequence et a base de films ceramiques
EP1944815A1 (fr) * 2007-01-09 2008-07-16 Konica Minolta Medical & Graphic, Inc. Élément piézoélectrique, fabrication et sonde ultrasonique
EP1949754A1 (fr) * 2005-10-29 2008-07-30 Dream Sonic Technology Limited Haut-parleur audio de type film à renforcement de bande médium/basse utilisant un film piézoélectrique en tant qu´élément vibrant
JP2009213137A (ja) * 2008-02-29 2009-09-17 General Electric Co <Ge> 超音波トランスジューサの感度を高めるための装置及び方法
CN105228065A (zh) * 2015-11-02 2016-01-06 李崇 具有良好音质效果的薄膜扬声器
CN105246011A (zh) * 2015-11-02 2016-01-13 李崇 兼具音响功能的相框
CN105246010A (zh) * 2015-11-02 2016-01-13 李崇 具有低音改善效果的薄膜扬声器
WO2020251557A1 (fr) * 2019-06-11 2020-12-17 Halliburton Energy Services, Inc. Transducteur de fond de trou commandé par signalisation manuelle
US11554387B2 (en) 2019-06-11 2023-01-17 Halliburton Energy Services, Inc. Ringdown controlled downhole transducer
US11770975B2 (en) 2019-09-09 2023-09-26 Halliburton Energy Services, Inc. Acoustic sensor self-induced interference control

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US3663842A (en) * 1970-09-14 1972-05-16 North American Rockwell Elastomeric graded acoustic impedance coupling device
FR2161949A1 (fr) * 1971-11-05 1973-07-13 Kureha Chemical Ind Co Ltd
DE2718772A1 (de) * 1976-04-27 1977-11-03 Tokyo Shibaura Electric Co Sonde fuer eine ultraschall- diagnosevorrichtung
GB1515287A (en) * 1974-05-30 1978-06-21 Plessey Co Ltd Piezoelectric transducers

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Publication number Priority date Publication date Assignee Title
US3663842A (en) * 1970-09-14 1972-05-16 North American Rockwell Elastomeric graded acoustic impedance coupling device
FR2161949A1 (fr) * 1971-11-05 1973-07-13 Kureha Chemical Ind Co Ltd
GB1515287A (en) * 1974-05-30 1978-06-21 Plessey Co Ltd Piezoelectric transducers
DE2718772A1 (de) * 1976-04-27 1977-11-03 Tokyo Shibaura Electric Co Sonde fuer eine ultraschall- diagnosevorrichtung

Non-Patent Citations (1)

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Title
ELECTRONICS LETTERS, Vol. 12, No. 16, 5th August 1976, pages 393, 394 London, G.B. L. BUI et al.: "Experimental Broadband Ultrasonic Transducers Using PVF2 Piezoelectric Film" * Page 393, left-hand column, paragraph 2 - page 394, right-hand column, line 8; figures * *

Cited By (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4383194A (en) * 1979-05-01 1983-05-10 Toray Industries, Inc. Electro-acoustic transducer element
FR2531298A1 (fr) * 1982-07-30 1984-02-03 Thomson Csf Transducteur du type demi-onde a element actif en polymere piezoelectrique
EP0100711A2 (fr) * 1982-07-30 1984-02-15 Thomson-Csf Transducteur du type demi-onde à élément actif en polymère piézoélectrique
US4473769A (en) * 1982-07-30 1984-09-25 Thomson-Csf Transducer of the half-wave type with a piezoelectric polymer active element
EP0100711A3 (fr) * 1982-07-30 1984-11-14 Thomson-Csf Transducteur du type demi-onde à élément actif en polymère piézoélectrique
US4549107A (en) * 1982-09-28 1985-10-22 Tokyo Shibaura Denki Kabushiki Kaisha Ultrasonic beam focusing device with a concave surface
FR2551611A1 (fr) * 1983-08-31 1985-03-08 Labo Electronique Physique Nouvelle structure de transducteur ultrasonore et appareil d'examen de milieux par echographie ultrasonore comprenant une telle structure
EP0142178A1 (fr) * 1983-08-31 1985-05-22 Laboratoires D'electronique Philips Transducteur ultrasonore
US5212671A (en) * 1989-06-22 1993-05-18 Terumo Kabushiki Kaisha Ultrasonic probe having backing material layer of uneven thickness
EP0404154A3 (fr) * 1989-06-22 1991-03-13 Terumo Kabushiki Kaisha Sonde à ultrasons avec couche de matériaux à épaisseur irrégulière
EP0404154A2 (fr) * 1989-06-22 1990-12-27 Terumo Kabushiki Kaisha Sonde à ultrasons avec couche de matériaux à épaisseur irrégulière
WO2004007098A1 (fr) * 2002-07-15 2004-01-22 Eagle Ultrasound As Transducteurs ultrasonores a bande haute frequence et multifrequence et a base de films ceramiques
EP1949754A1 (fr) * 2005-10-29 2008-07-30 Dream Sonic Technology Limited Haut-parleur audio de type film à renforcement de bande médium/basse utilisant un film piézoélectrique en tant qu´élément vibrant
EP1949754A4 (fr) * 2005-10-29 2009-04-08 Dream Sonic Technology Ltd Haut-parleur audio de type film à renforcement de bande médium/basse utilisant un film piézoélectrique en tant qu´élément vibrant
EP1944815A1 (fr) * 2007-01-09 2008-07-16 Konica Minolta Medical & Graphic, Inc. Élément piézoélectrique, fabrication et sonde ultrasonique
JP2009213137A (ja) * 2008-02-29 2009-09-17 General Electric Co <Ge> 超音波トランスジューサの感度を高めるための装置及び方法
CN105228065A (zh) * 2015-11-02 2016-01-06 李崇 具有良好音质效果的薄膜扬声器
CN105246011A (zh) * 2015-11-02 2016-01-13 李崇 兼具音响功能的相框
CN105246010A (zh) * 2015-11-02 2016-01-13 李崇 具有低音改善效果的薄膜扬声器
WO2020251557A1 (fr) * 2019-06-11 2020-12-17 Halliburton Energy Services, Inc. Transducteur de fond de trou commandé par signalisation manuelle
US11554387B2 (en) 2019-06-11 2023-01-17 Halliburton Energy Services, Inc. Ringdown controlled downhole transducer
US11770975B2 (en) 2019-09-09 2023-09-26 Halliburton Energy Services, Inc. Acoustic sensor self-induced interference control

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