WO2002090242A2 - Transducteur electroacoustique pour produire ou acquerir des ultrasons, reseau de transducteurs et procede de production de ce transducteur et de ce reseau de transducteurs - Google Patents

Transducteur electroacoustique pour produire ou acquerir des ultrasons, reseau de transducteurs et procede de production de ce transducteur et de ce reseau de transducteurs Download PDF

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Publication number
WO2002090242A2
WO2002090242A2 PCT/EP2002/004869 EP0204869W WO02090242A2 WO 2002090242 A2 WO2002090242 A2 WO 2002090242A2 EP 0204869 W EP0204869 W EP 0204869W WO 02090242 A2 WO02090242 A2 WO 02090242A2
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WO
WIPO (PCT)
Prior art keywords
membrane
different
substrate
zones
transducer
Prior art date
Application number
PCT/EP2002/004869
Other languages
German (de)
English (en)
Other versions
WO2002090242A3 (fr
Inventor
Oliver Ahrens
Andreas Buhrdorf
Josef Binder
Original Assignee
Campus Micro Technologies Gmbh
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
Application filed by Campus Micro Technologies Gmbh filed Critical Campus Micro Technologies Gmbh
Priority to AU2002310796A priority Critical patent/AU2002310796A1/en
Publication of WO2002090242A2 publication Critical patent/WO2002090242A2/fr
Publication of WO2002090242A3 publication Critical patent/WO2002090242A3/fr

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B81—MICROSTRUCTURAL TECHNOLOGY
    • B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
    • B81B3/00—Devices comprising flexible or deformable elements, e.g. comprising elastic tongues or membranes
    • B81B3/0035—Constitution or structural means for controlling the movement of the flexible or deformable elements
    • 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
    • B06B1/0292—Electrostatic transducers, e.g. electret-type

Definitions

  • Electroacoustic transducer for generating or detecting ultrasound, transducer array and method for producing the transducer or transducer array
  • the invention relates to an electroacoustic transducer for generating or detecting ultrasound, with a solid, rigid substrate, a flexible membrane made of a semiconductor material, the edge of which is attached to the substrate, a cavity between the membrane and the substrate, and electrodes for applying or tapping a voltage between the membrane and the substrate, the membrane being doped with solids.
  • the invention further relates to an array constructed from such transducers and a method for producing such transducers or transducer arrays.
  • Such electroacoustic transducers are known and come in a number of commercial applications, for example in the non-destructive material testing or medical diagnostics. With the aid of such transducers, systems for distance measurement or for flow measurement can be implemented, or shape features can be recorded in acoustically transparent bodies, for example the human body, by means of imaging methods.
  • the flexible membrane is deflected by means of an electrical alternating voltage to generate ultrasound, at a frequency which corresponds to the mechanical resonance frequency of the system.
  • the usable ultrasound is generated by the mechanical periodic deflection of the membrane and the alternating compression and dilution of the gas or liquid environment in the form of pressure gradients on the front of the membrane.
  • the mechanical resonance of the membrane is determined in particular by the mechanical rigidity of the membrane and its clamping and the nature of the cavity located below the membrane.
  • the mechanical rigidity is in turn determined on the one hand by the geometric dimensions of the flexible membrane and on the other hand by its mechanical residual stress and other material parameters.
  • the known electroacoustic transducers which work as membrane vibrators, can only be operated in a relatively low frequency range due to their design, which is determined by the width of the resonance increase of the transducer, that is to say by its usable bandwidth.
  • converters with a low active bandwidth are disadvantageous for use as an image converter in imaging ultrasound diagnostic methods, since pulse-shaped signals and their different transit times have to be detected by different substances, for example body tissue, during image processing.
  • the flexible membrane is made of insulator material, and the electrode connected to the membrane is applied to the membrane as a metal layer, so that in addition to the cavity, the membrane thickness is also present between the first substrate-fixed electrode and the second electrode is, whereby the resting capacity around which the change in capacity due to a membrane deflection takes place is correspondingly smaller, the detection of the change in capacity and thus of the ultrasound is less sensitive.
  • transducers of the type mentioned are known, in which the flexible membrane consists of a uniformly doped polycrystalline silicon material. Due to a relatively high doping with dopants, the membrane has good conductivity and can therefore be used as a counter electrode to the base electrode fixed to the substrate. As a result, the ratio of change in capacity and resting capacity when the membrane is deflected during ultrasound generation / exposure is greater, and the sensitivity with which ultrasound can be detected is correspondingly greater.
  • the object of the invention is to develop a converter or a converter array of the type mentioned at the outset in such a way that the usable bandwidth of the converter or of the array is increased. It is also an object to specify a method for producing the converter or the converter array.
  • the advantages of the invention are, in particular, that the different doping of different local zones or areas of the membrane with foreign substances and / or the different masses of these zones, the material-specific or manufacturing-specific properties, such as the modulus of elasticity, the membrane density or the Poisson number Semiconductor material or the membrane thickness and the membrane internal stress changed so that zones of different mechanical material properties arise with the result that the different zones of the membrane have different discrete resonance frequencies, whereby the usable bandwidth of the transducer - with superposition of the individual resonances - is broadened.
  • the material-specific or manufacturing-specific properties such as the modulus of elasticity, the membrane density or the Poisson number Semiconductor material or the membrane thickness and the membrane internal stress changed so that zones of different mechanical material properties arise with the result that the different zones of the membrane have different discrete resonance frequencies, whereby the usable bandwidth of the transducer - with superposition of the individual resonances - is broadened.
  • a first electrode also referred to as a base electrode
  • the substrate preferably consists of semiconductor material.
  • the substrate can also be implemented as a base body made of insulator material with an upper semiconductor layer.
  • the first electrode or base electrode is preferably realized by a highly doped conductive zone in the substrate.
  • dopants that is to say donors or acceptors, as foreign substances for doping the various membrane zones which, in addition to changing the mechanical properties of the semiconductor material, also change the electrical properties.
  • a central zone of the membrane is preferably particularly heavily doped with donors or acceptors and thus has a high conductivity, on the basis of which the membrane itself can be switched as a second electrode and forms the counter electrode to the base electrode.
  • the two electrodes which are used to apply the generator voltage or to tap the voltage changes / capacitance changes generated, are located directly at the boundary layer with the cavity, and are therefore at a particularly small distance from one another, as a result of which the corresponding resting capacity or the capacitance changes are particularly large are.
  • the transducer therefore has a greater sensitivity than in embodiments in which the electrodes are at a greater distance from one another. Due to the high dopant concentration N of individual local zones, i.e.
  • the corresponding zones become electrical conductors or electrodes.
  • the capacitance present between the base electrode and the counter electrode is influenced, undesired capacitance components are reduced, which otherwise form in particular at the edge region of the membrane and reduce the signal-to-noise ratio.
  • the membrane is preferably attached or clamped to the substrate with its periphery all around an insulating intermediate layer.
  • the local doping of a defined, locally restricted zone of the membrane is carried out using the known methods for structured material introduction.
  • N becomes influences the mechanical properties of these zones differently.
  • the modulus of elasticity and / or the Poisson number and / or the membrane density and the mechanical residual stress of the membrane clamped circumferentially on the edge of the substrate are changed locally accordingly, and in this particular embodiment is reduced with increasing foreign substance concentration.
  • the residual stress is a measure of the rigidity of the membrane zone in question. Due to the changed stiffness, the highly doped zone in question has a different mechanical resonance than the entire membrane, including the highly doped zone. Overall, a resulting residual stress occurs in the membrane, which differs from the residual stress of the membrane, which is homogeneous over the entire surface.
  • either the membrane on its underside or the substrate on its top carries an insulating layer. This prevents the membrane and substrate from touching each other and forming electrical contact that could damage the transducer.
  • a circumferential third zone can be provided between the heavily doped central zone and the weakly doped or undoped edge zone, which circulates concentrically around the central zone and whose foreign substance concentration N is different from that of the other two zones.
  • An intermediate zone can also be arranged between the concentrically rotating third zone and the central first zone, which has its own foreign substance concentration N which differs from the other foreign substance concentrations, but which, like the peripheral zone, is preferably undoped or weakly doped.
  • the differently doped zones can also be arranged arbitrarily, for example next to one another or as islands within other zones.
  • the shape of the membrane is preferably round or square or hexagonal or polygonal.
  • monocrystalline silicon is used as the material for the substrate, the surface of which adjoins the cavity has a heavily doped and thus highly conductive zone, which represents the base electrode.
  • the base electrode can itself be electrically contacted via a highly doped semiconductor structure introduced into the substrate.
  • the membrane consists of polycrystalline silicon, which is weakly or not doped at the edge and also has a high doping concentration N in the central zone.
  • N means the impurity concentration when the membrane is doped with any suitable impurity atoms, but in particular also when doping with dopants, ie donors or acceptors. In the latter case, N is also referred to as the doping concentration or dopant concentration.
  • the invention also relates to an array of a plurality of capacitive membrane oscillators, all of which are arranged on a common, rigid, rigid substrate and have a structure according to one of Claims 1 to 16.
  • the membranes in such an array of ultrasonic transducers are all of the same size.
  • the membranes have different sizes and / or different thicknesses in order to design the resonance frequencies of the individual transducers differently.
  • the membranes of the individual transducers can also be doped to different extents with foreign substances and / or be provided with different mass assignments, in order in this way to differentiate the mechanical residual stress ranges of the individual transducers even more strongly.
  • the membranes and the transducers all have the same structure and the same size.
  • neighboring membranes however, local zones of comparatively different sizes are provided with a high concentration of foreign matter and / or different masses, which can also be of different heights in neighboring membranes, as a result of which the mechanical residual stresses of the adjacent transducers differ from one another.
  • the invention also relates to a method for producing a converter or a converter array, the construction of which is designed according to one of Claims 1 to 24. In the process, a flexible membrane made of semiconductor material is attached all around at its edge to a rigid and rigid substrate.
  • the dopants known in semiconductor technology are preferably used as foreign substances, which change their electrical properties in addition to the mechanical properties of the membrane when they are introduced.
  • the thickness of the membrane is set differently by material application or material removal, and thus the mass assignment of the membrane.
  • the thickness of the membrane is either removed locally by chemical or physical etching, or material is applied locally by chemical or physical deposition from the vapor phase.
  • FIG. 1 shows a diagram which shows the mechanical residual stress of a membrane and the specific surface resistance as a function of time and type of treatment, which are present in a membrane during a recrystallization phase and a subsequent doping phase;
  • FIG. 3 shows a perspective view of a transducer array comprising a plurality of transducers with rectangular membranes arranged in rows and columns;
  • the membrane shows the mechanical residual stress, measured in MPa, and the specific surface resistance, measured in ohm / sq, as is typically present in the case of crystallization or recrystallization of a membrane and in a subsequent doping step.
  • the membrane consists of a thin semiconductor layer of approximately 0.5 to 2 ⁇ m. It is remarkable that during a recrystallization phase the mechanical internal stress of the membrane, i.e. the voltage in the membrane plane can be negative at first and increases sharply with increasing crystallization time, so that the membrane becomes more and more tense with increasing crystallization and therefore always stiffer. If the membrane is subsequently doped, the mechanical residual stress as a function of the doping time and concentration decreases again sharply. In addition, the specific resistance decreases.
  • Fig. 1 The physical effect shown in Fig. 1 can be used according to the invention to determine the mechanical properties of the membrane of a capacitive electroacoustic transducer manufactured on a semiconductor basis, i.e. to be set differently in different subareas or zones.
  • N With a low doping concentration N, there is a comparatively high mechanical residual stress; with increasing doping concentration, this residual stress is reduced.
  • FIG. 2a to 2c show a cross section through a capacitive electroacoustic transducer at different times during its manufacture.
  • 2d shows an alternative embodiment to the representation according to FIG. 2c.
  • a semiconductor substrate 2 is provided on its surface with a highly doped zone 4, which serves as the first electrode or base electrode of the converter and is led to the outside with a connecting line.
  • One or more sacrificial layers are arranged above the first electrode 4, an insulating layer 12 is arranged outside the base electrode 4 and outside the sacrificial layer.
  • a thin semiconductor layer 7 is applied over the sacrificial layer 5, which can consist of several material layers, which in the example shown is undoped or has only a weak doping concentration N.
  • the semiconductor layer 7 is then in the outer, the sacrificial layers 5 partially overlapping zones, for example by means of a Photoresists 30 covered.
  • the photoresist-free central zone of the semiconductor layer 7, which is located above the base electrode 4 and the sacrificial layers 5 above, is then subjected to a doping step and thereby receives a high doping concentration of dopants, for example donors or acceptors.
  • the photoresist 30 is then removed.
  • the membrane layer is then structured and thereby receives its final lateral dimensions, for example a round or square, hexagonal or polygonal shape. Then the sacrificial layers 5 are removed, in this way the cavity 6 is created.
  • the membrane 8 is connected circumferentially to the substrate at its edge by means of already existing or still to be applied insulating layers 12 and thus completely clamped in at the edge.
  • a metallic connecting line 20 is applied, which is connected either via a highly conductive web at the edge of the membrane to the central, highly doped and thus highly electrically conductive zone Z ⁇ cf. 2c and 4b or directly to the central zone Zj and contacted with this, cf. Fig. 2d.
  • the substrate 2c shows the typical structure of a capacitive electroacoustic ultrasound transducer based on semiconductor material in cross section.
  • the substrate 2 contains a first electrode 4, the base electrode, which is implemented as a highly doped zone in the substrate 2.
  • a cavity 6 is located above it, and above the cavity is the thin, flexible membrane 8, which likewise consists of semiconductor material and is clamped against the substrate 2 at its edge by means of suitable insulating layers 12.
  • the membrane 8 according to FIG. 2 c has differently doped zones Z which have a different doping concentration N either from acceptors A or donors D.
  • the central zone Z 1 is provided with a high doping concentration Ni.
  • This zone Zi therefore has - according to the diagram in FIG. 1 - a low mechanical residual stress.
  • the edge zone Z 2 is not or only weakly doped, it has the doping concentration N 2 .
  • This edge zone Z 2 therefore has a comparatively high mechanical internal stress and therefore rigidity, cf. Fig. 1.
  • the highly conductive central zone Zi is used as the second electrode - also called the membrane electrode - because of the highly conductive properties of this central area can be dispensed with the otherwise usual additional application of a metal electrode to the membrane 8.
  • the two electrodes 4, Zi are aligned one above the other, they end laterally at a predetermined distance in front of the clamped and thus immovable edge of the membrane 8. This ensures that the capacitance between the electrodes 4 and only in that area of the membrane 8 that is defined takes part in the movement of the membrane 8, caused by an applied voltage or by incident ultrasound. Unused portions of the quiescent capacitance and also parasitic capacitances of supply lines are not detected via the two electrodes 4, Z ⁇ , and therefore do not reduce the sensitivity.
  • FIG. 2c shows the embodiment of the converter in which the highly doped central zone Z contains a narrow, web-shaped section which extends to the edge of the membrane 8 and is contacted there directly by an electrical connecting line 20.
  • Such a configuration of the membrane is, for example, also shown in a top view in FIG. 4b.
  • FIG. 2d shows an embodiment of the converter in which the highly doped central zone is completely surrounded by the weak or undoped edge zone Z 2 .
  • the edge zone Z 2 is covered at one point - on the left in the cross section shown - by an insulating layer 12, and the electrical connection line 20 is guided via this insulating layer 12 into the central zone Zi in order to contact the central zone Zi there ,
  • FIG. 3 shows an array of several transducers, which is arranged on a semiconductor substrate 2 and each has a first electrode 4 and a rectangular membrane 8 above it. Electrical connection lines 22 run between the membranes in order to contact the electrodes 4, Zi.
  • FIG. 4 shows plan views of various membranes 8, all of which have a quadratic basic shape and various, differently doped zones Zi, Z 2, Z 3 and Z. ... each with the associated different foreign substance concentrations Ni, N 2 , N 3 and N 4 ..., whereby in principle all chemical elements can be used as foreign substances.
  • Fig. 5 also shows top views of different membranes in different zones Z 2 ... are provided with different concentrations of foreign substances N 1 ⁇ N 2 ... While the membranes according to FIG. 4 have a square total area, the membranes 8 according to FIG. 5 are either round, hexagonal or square.
  • two separate zones Z 3 , Z 4 are provided with a high concentration of dopants N 3 , N 4 , the remaining areas of the membranes, also called base zone Z G , enclose the edge zone Z 2 and have the weak doping concentration N. 2 or are not endowed.
  • At least one highly doped zone for example the central zone Z ⁇ with the doping concentration, is introduced at the base zone Z G , which also contains the edge zone Z 2 with the weak doping concentration N 2 .
  • further circumferential zones Z 3 with the high concentration N 3 and zone Z 4 with the high concentration N 4 are at a short distance from the central zone Z ⁇ arranged from the adjacent zones, the doping of the highly doped zones having an identical concentration or different concentrations N of foreign substances.
  • FIG. 6 shows the schematic top view of several transducers within different transducer arrays.
  • the array A is designed in accordance with the prior art, in which all transducers have an identical membrane which is identical in terms of size, shape and doping. All individual converters therefore have a sharp resonance frequency at which the membrane can be set in mechanical vibrations, ie the bandwidth B of the transducer array is small, cf.
  • Figure 6b shows the schematic top view of several transducers within different transducer arrays.
  • the array A is designed in accordance with the prior art, in which all transducers have an identical membrane which is identical in terms of size, shape and doping. All individual converters therefore have a sharp resonance frequency at which the membrane can be set in mechanical vibrations, ie the bandwidth B of the transducer array is small, cf.
  • Figure 6b shows the schematic top view of several transducers within different transducer arrays.
  • each transducer thus has two different resonance frequencies, first the entire membrane, ie the edge zone together with the central zone, resonates, with a different frequency the less rigid central zone Zi then resonates alone.
  • the overlaying of two resonances results in a broadening of the active bandwidth of the array, cf. Fig. 6d.
  • 6e shows a transducer array in which the central zones Zi, Z 3 are again heavily doped with the concentration N, while the edge zones Z 2 have a weak doping.
  • the highly doped zones Z have different sizes in different converters. This constellation results in at least two and up to four discrete mechanical resonances, the total usable bandwidth resulting from a superimposition of these resonances is increased, cf. 6f.
  • FIG. 6g shows a transducer array in which the membranes all have the same area and in which the central, highly doped zones Zi also all have the same size.
  • some transducers have a high doping concentration Nu
  • other transducers have a different high doping concentration N 2 .
  • the transducer field shown has at least two and up to four discrete mechanical resonance frequencies. The usable total bandwidth resulting from superimposition is correspondingly large, cf. Fig. 6h.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Transducers For Ultrasonic Waves (AREA)
  • Ultra Sonic Daignosis Equipment (AREA)
  • Pressure Sensors (AREA)

Abstract

L'invention concerne un transducteur électroacoustique et un réseau de transducteurs pour produire ou acquérir des ultrasons, comprenant un substrat solide résistant à la flexion, une membrane flexible en matériau semi-conducteur fixée par son bord au substrat, une cavité située entre la membrane et le substrat, ainsi que des électrodes pour appliquer ou prélever une tension entre la membrane et le substrat. L'invention se caractérise en ce qu'au moins deux zones locales différentes (Z1, Z2) de la membrane (8) présentent des niveaux différents de concentration en corps étrangers (N1, N2) et/ou d'occupation de masse (M1, M2).
PCT/EP2002/004869 2001-05-10 2002-05-03 Transducteur electroacoustique pour produire ou acquerir des ultrasons, reseau de transducteurs et procede de production de ce transducteur et de ce reseau de transducteurs WO2002090242A2 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU2002310796A AU2002310796A1 (en) 2001-05-10 2002-05-03 Electroacoustic transducer for generating or detecting ultrasound, transducer array and method for the production of the transducer or the transducer array

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE10122765.5 2001-05-10
DE2001122765 DE10122765A1 (de) 2001-05-10 2001-05-10 Elektroakustischer Wandler zur Erzeugung oder Erfassung von Ultraschall, Wandler-Array und Verfahren zur Herstellung der Wandler bzw. der Wandler-Arrays

Publications (2)

Publication Number Publication Date
WO2002090242A2 true WO2002090242A2 (fr) 2002-11-14
WO2002090242A3 WO2002090242A3 (fr) 2004-01-08

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AU (1) AU2002310796A1 (fr)
DE (1) DE10122765A1 (fr)
WO (1) WO2002090242A2 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1764162A1 (fr) * 2005-09-14 2007-03-21 Esaote S.p.A. Transducteur capacitif ultrasonique microfabriqué pour applications haute fréquence
FR2952626A1 (fr) * 2009-11-19 2011-05-20 St Microelectronics Tours Sas Microtransducteur capacitif a membrane vibrante
WO2017216139A1 (fr) * 2016-06-13 2017-12-21 Koninklijke Philips N.V. Transducteur à ultrasons à large bande

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102005004878B4 (de) * 2005-02-03 2015-01-08 Robert Bosch Gmbh Mikromechanischer kapazitiver Drucksensor und entsprechendes Herstellungsverfahren

Citations (6)

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Publication number Priority date Publication date Assignee Title
DE4318466A1 (de) * 1993-06-03 1994-12-08 Bosch Gmbh Robert Mikromechanischer Sensor und Verfahren zu dessen Herstellung
US5583296A (en) * 1993-01-19 1996-12-10 Fraunhofer-Gesellschaft Zur Forderung Der Angewandten Forschung E. V. Layered diaphragm pressure sensor with connecting channel
US5682053A (en) * 1992-03-30 1997-10-28 Awa Microelectronics Pty. Limited Silicon transducer with composite beam
DE19643893A1 (de) * 1996-10-30 1998-05-07 Siemens Ag Ultraschallwandler in Oberflächen-Mikromechanik
US5870351A (en) * 1994-10-21 1999-02-09 The Board Of Trustees Of The Leland Stanford Junior University Broadband microfabriated ultrasonic transducer and method of fabrication
DE19922967A1 (de) * 1999-05-19 2000-12-07 Siemens Ag Mikromechanischer kapazitiver Ultraschallwandler und Verfahren zu dessen Herstellung

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5682053A (en) * 1992-03-30 1997-10-28 Awa Microelectronics Pty. Limited Silicon transducer with composite beam
US5583296A (en) * 1993-01-19 1996-12-10 Fraunhofer-Gesellschaft Zur Forderung Der Angewandten Forschung E. V. Layered diaphragm pressure sensor with connecting channel
DE4318466A1 (de) * 1993-06-03 1994-12-08 Bosch Gmbh Robert Mikromechanischer Sensor und Verfahren zu dessen Herstellung
US5870351A (en) * 1994-10-21 1999-02-09 The Board Of Trustees Of The Leland Stanford Junior University Broadband microfabriated ultrasonic transducer and method of fabrication
DE19643893A1 (de) * 1996-10-30 1998-05-07 Siemens Ag Ultraschallwandler in Oberflächen-Mikromechanik
DE19922967A1 (de) * 1999-05-19 2000-12-07 Siemens Ag Mikromechanischer kapazitiver Ultraschallwandler und Verfahren zu dessen Herstellung

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1764162A1 (fr) * 2005-09-14 2007-03-21 Esaote S.p.A. Transducteur capacitif ultrasonique microfabriqué pour applications haute fréquence
US7477572B2 (en) 2005-09-14 2009-01-13 Esaote, S.P.A. Microfabricated capacitive ultrasonic transducer for high frequency applications
FR2952626A1 (fr) * 2009-11-19 2011-05-20 St Microelectronics Tours Sas Microtransducteur capacitif a membrane vibrante
WO2017216139A1 (fr) * 2016-06-13 2017-12-21 Koninklijke Philips N.V. Transducteur à ultrasons à large bande
CN109311055A (zh) * 2016-06-13 2019-02-05 皇家飞利浦有限公司 宽带超声换能器
US11400487B2 (en) 2016-06-13 2022-08-02 Koninklijke Philips N.V. Broadband ultrasound transducer

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Publication number Publication date
AU2002310796A1 (en) 2002-11-18
DE10122765A1 (de) 2002-12-05
WO2002090242A3 (fr) 2004-01-08

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