EP0031614B2 - Curved array of sequenced ultrasound transducers - Google Patents

Curved array of sequenced ultrasound transducers Download PDF

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Publication number
EP0031614B2
EP0031614B2 EP19800201181 EP80201181A EP0031614B2 EP 0031614 B2 EP0031614 B2 EP 0031614B2 EP 19800201181 EP19800201181 EP 19800201181 EP 80201181 A EP80201181 A EP 80201181A EP 0031614 B2 EP0031614 B2 EP 0031614B2
Authority
EP
European Patent Office
Prior art keywords
elements
array
transducer elements
active group
ultrasound
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.)
Expired
Application number
EP19800201181
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German (de)
English (en)
French (fr)
Other versions
EP0031614B1 (en
EP0031614A1 (en
Inventor
James W. Pell
Gerald L. Hansen
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.)
Philips North America LLC
Original Assignee
North American Philips Corp
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Publication date
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Application filed by North American Philips Corp filed Critical North American Philips Corp
Publication of EP0031614A1 publication Critical patent/EP0031614A1/en
Application granted granted Critical
Publication of EP0031614B1 publication Critical patent/EP0031614B1/en
Publication of EP0031614B2 publication Critical patent/EP0031614B2/en
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    • 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
    • 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
    • G10K11/34—Sound-focusing or directing, e.g. scanning using electrical steering of transducer arrays, e.g. beam steering
    • G10K11/341—Circuits therefor
    • G10K11/345—Circuits therefor using energy switching from one active element to another

Definitions

  • the invention relates to an apparatus for producing and/or receiving a sector-scanned beam of ultrasound energy that is suitable to be directed through a space between obstacles to scan a region behind the obstacles, the apparatus comprising:
  • Internal body organs may be imaged and otherwise characterized by apparatus which directs pulses of ultrasound energy into the body and subsequently detects echos which originate when the energy is reflected from tissue interfaces or other discontinuities within the body.
  • the ultrasound energy is directed into the body in a relatively narrow beam.
  • Electric signals which describe the position and direction of the beam with respect to the body, as well as the relative arrival time and amplitude of the echos, are utilized to generate a visual display and/or mapping of the internal body structures.
  • the direction of the ultrasound beam is manually controlled by a technician (generally by physical motion of a probe head) to build up a display pattern.
  • Ultrasound systems for generating real time displays of rapidly moving body organs generally utilize electromechanical or electronic means to change the position and direction of one or more beams of ultrasound energy with respect to the body.
  • Motion of a beam of ultrasound energy with respect to the body may be provided by sequentially activating transducer elements in a flat linear array to effectively scan an area of the body with a sequence of substantially parallel ultrasound beams.
  • a device of this type is described in US-A-3,013,170.
  • a beam of ultrasound energy may, alternately, be scanned around a single origin point to produce a so-called "sector-scan".
  • Sector-scan geometries are particularly useful since ultrasound energy may be directed between the ribs to scan the interior of the chest cavity.
  • Sector scanning has been achieved in the prior art by rapidly rotating one or more transducers about an axis, by steering energy from a fixed transducer with a rotating ultrasound reflector, or by sequencing individual transducer elements in a linear curved array.
  • DE-A-2,818,915 describes a curved transducer array with individual transducers which are individually activated to produce a sector-scan.
  • the transverse spatial resolution which may be obtained from a sequence array of ultrasound transducers is related to dimensions of the individual transducer elements in the array. Small transducer elements are desirable for obtaining fine resolution.
  • the amount of ultrasound energy produced by an individual transducer element is, however, limited by its size.
  • the signal-to-noise ratio of the returned ultrasound echos necessarily depends on the amount of ultrasound energy introduced into the body. Thus, the signal to noise ratio suffers if small transducer elements are individually activated to achieve a scanning action. Diffraction effects will furthermore, cause spreading of an ultrasound beam which originates from a single, small ultrasound transducer element.
  • the ultrasonic beam is directed through a small window in order to decrease its lateral dimensions, thereby decreasing the amount of energy in the beam even further.
  • This apparatus comprises a sequenced group curved array of transducers in which the focus is slightly displaced to a point at a distance from the array of about 1 2/3 times the natural focual distance. This displacement of the focus is obtained by activating the outer transducers of the group with a signal having a 90° phase shift relative to the signal activating the transducers located near the center of the group. In this manner an acceptable resolution is obtained only in a very limited area around the new focus.
  • the apparatus according to the invention is characterized in that it further comprises:
  • the invention also relates to a method for manufacturing a curved array of ultrasound transducer elements for such an apparatus, comprising the steps of:
  • Figure 1 is a linear array of ultrasound transducers 110 which is known in the prior art.
  • a series of individual transducers elements 100 are disposed along a line 101.
  • Separate electrodes 102 are provided for each transducer in the array and are connected to electronic circuits (not shown) which permit sequential activation of the elements to, in effect, move the source of an ultrasound beam along the line 101.
  • Figure 2 illustrates an application of the array 110 of Figure 1.
  • a group of adjacent transducers 111 are simultaneously activated to produce a beam of ultrasound energy 112 which is inwardly projected into a body 113.
  • the array 110 is disposed on the surface of a probe assembly 114 which includes switching circuits 115.
  • the switching circuits act to incrementally shift the group of active transducers 111 along the array to generate a linear scan of the beam 112 with respect to the body.
  • the operation of prior art imaging systems with incrementally shifted arrays is described in the articles Ultrasonic Imaging Using Arrays, Albert Macovski and Methods and Terminology for Diagnostic Ultrasound Imaging Systems, Maxwell G. Maginness in the Proceedings of the IEEE, Vol. 67, No. 4, April 1979 at page 484 and 641 respectively.
  • British patent Specification 1,546,445 describes a curved linear array of transducers which are individually activated to generate a sector-scanned ultrasound beam.
  • a positive (converging) lens is utilized with the transducer array to focus the beam through the spaces between the ribs. Because only one transducer element is active at a time, the array of British patent 1,546,445 suffers from relatively low spatial resolution and signal-to-noise ratio. The performance of the array cannot, however, be improved by directly applying the incrementally shifted active group geometry of Figure 2 to the curved array configuration.
  • the simultaneous activation of a group of adjacent elements on a curved array necessarily produces a sharply focussed beam which diverges in the far field and is unsuitable for medical imaging.
  • FIG. 3 schematically illustrates a transducer array of the present invention.
  • a plurality of electro- acoustic transducer elements 200 are disposed along an arc and are oriented to project and receive ultrasound energy in the direction of the center of the arc.
  • the individual elements 200 in the array are provided with separate electrodes and are connected via wires 202, and a sequencing circuit to pulse generator and receiver circuits (not shown).
  • the array is contained in a housing 204 which includes an ultrasound transmissive window 206.
  • the housing may be filled with an ultrasound transmissive fluid 208, for example, castor oil, which is matched to the ultrasound transmissive properties of the human body. Alternately the housing may be filled with a solid material. In general the filling should have an acoustic attenuation between those of water and human tissue and should have an acoustic impedance which is matched to the impedance of human tissue.
  • a group of adjacent transducer elements (for example 220) within the array is activated for the transmission and reception of each ultrasound pulse.
  • the active group of transducers is incrementally shifted along the array, one transducer at a time, on a pulse to pulse basis to provide a sector scan of ultrasound energy.
  • Defocussing means are included to compensate for the strong inherent focussing of the curved array.
  • the curved array, with an incrementally shifted group of active detectors, in combination with the defocussing means, produces a finer spatial resolution and higher signal to noise ratio than curved sequenced arrays of the prior art.
  • FIG. 4 illustrates a preferred embodiment of the defocussing means.
  • a group 220 of adjacent transducers A-K within the array is activated by sequencing switches (not shown for the sake for clarity).
  • the central transducer F within the zone is connected directly to ultrasound pulse generator 240 and receiver 250 circuits via a transmit-receive (TR) switch 260.
  • TR transmit-receive
  • the transducer pair E and G immediately adjacent the central transducer is connected to the TR switch 260 via a first delay 270.
  • the next adjacent pair of transducers D and H are connected to the TR switch through a second delay circuit 280 which provides a longer delay than the delay circuit 270.
  • Each next adjacent pair of transducers within the group i.e.
  • C and I, B and J, A and K are connected to the TR switch via delay circuits (290,300,310) which provide increasing delays in proportion to the distance from the center of the active group to the associated transducers.
  • the magnitude of the delays are chosen, using techniques which are well known in the art and which are described, for example, in the above referenced Macovski article, to compensate for the physical focussing effects of the curved array and thus provide a more parallel beam of ultrasound energy. Alternately the beam may thus be focussed at a point deep within the body of a patient.
  • Figure 5 illustrates a system for incrementally shifting the active group along the transducer array.
  • Pulsers 400, receiver amplifiers 410, and associated TR isolators 420 are connected in a conventional fashion to first ends of a bank of bidirectional delay lines 430.
  • the bank of delay lines 430 includes delay lines of varying time delay which are calculated to provide the defocussing compensation for the active group as described above with respect to the Figure 4.
  • the opposite end of each delay line in the bank 430 is connected to a row of switches in an analog switch matrix 440.
  • Each column of switches in the switch matrix 440 is connected to a separate element 200 in the transducer array 450.
  • a separate switch (which may be a MOS transistor) is provided at each cross point (that is the intersection of each row with each column) in the switch matrix.
  • the switching elements are individually activated by the output lines of a read-only memory (ROM) 460.
  • Input lines of the read-only memory 460 are addressed by the output of a sequencer circuit which may be a sequential counter 470 driven by a clock 480.
  • the sequencer circuit addresses consecutive words in the read-only memory which establish the connection patterns between the individual transducer elements in the array and corresponding delay lines to effect incremental shifting of a defocussed, active group along the array.
  • Table I illustrates the first three words of a read-only memory which shifts an active group of nine transducer elements along an array by establishing connections to four delay lines I through IV.
  • bit patterns of Table I are shortened for the sake of clarity of illustration; the principles illustrated therein may be extended to active groups and arrays which include larger or smaller numbers of transducer elements.
  • Figure 6 is an alternate embodiment of a transducer array wherein the defocussing means comprise a negative lens 500.
  • a group of transducers is sequentially shifted across the array as in the embodiment of Figure 3 to produce a sector scan. All of the transducers in the group 200 may be simultaneously pulsed.
  • the delay line defocussing means of Figure 4 may be utilized in conjunction with the lens 500.
  • the lens may be constructed from metal or plastic and may advantageously comprise two negative lens elements separated by a fluid-filled cavity 510.
  • FIG. 7 illustrates first steps in a preferred method for manufacturing the transducer array.
  • the array is advantageously formed from a single rectangular bar 600 of piezo-electric ceramic (which may comprise Type PZT-5). Copper electrodes 605 and 610 are bonded to the front 601 and rear 602 major surfaces of the bar with a silver bearing epoxy resin.
  • a flexible matching window 615 is then cast directly on the front electrode.
  • the matching window may be advantageously cast from a mixture of two parts of a Stycast 1264 resin binder and one part tungsten powder. The window is cast by pouring the mixture directly onto the surface of the front electrode and allowing the tungsten powder to settle. After the resin is cured, the window is machined to a thickness of one quarter acoustic wavelength at the operating frequency of the array. For example, a window designed for operation at 3.5 MHz is machined to approximately 0.09 mm thickness.
  • a series of parallel grooves 620 are then cut through the rear electrode 610 and into the upper surface of the bar to segregate individual transducer elements 630 with their associated rear electrodes.
  • the grooves are approximately 0.13 mm wide and penetrate to 75% of the thickness of the ceramic bar.
  • the ceramic bar is approximately 80.5 millimeters long, 12.5 millimeters wide, and 2.0 millimeters thick.
  • the bar is divided by 71 saw cuts to form 72 transducer elements.
  • the rear electrodes on the endmost transducer elements are grounded to the front electrode so that the array comprises 70 functional transducer elements.
  • Figures 8 and 9 illustrate the further construction of the array.
  • the grooved ceramic bar 600 with attached electrodes 605 and 610 and window 615 is formed around a semi-cylindrical mandrel 650, the grooves in the bar being parallel to the axis of the cylinder.
  • the bar cracks under each groove 620 to produce a curved array of separate, electroded transducer elements 630 which are retained in place by the front electrode 605 and window 615.
  • a supporting foam air cell 660 is then cast between the elements 630 and around the rear surface of the curved transducer array.
  • the air cell retains the transducer elements in place and further provides a low acoustic impedance backing for the individual elements.
  • the air cell may typically comprise glass microballoons in an epoxy resin binder.
  • the upper electrodes 610 are wider than the ceramic bar and are folded back along the edges of the air cell to provide electrical connections to the individual elements.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Multimedia (AREA)
  • Ultra Sonic Daignosis Equipment (AREA)
  • Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)
  • Transducers For Ultrasonic Waves (AREA)
EP19800201181 1979-12-17 1980-12-09 Curved array of sequenced ultrasound transducers Expired EP0031614B2 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US10451679A 1979-12-17 1979-12-17
US104516 1979-12-17

Publications (3)

Publication Number Publication Date
EP0031614A1 EP0031614A1 (en) 1981-07-08
EP0031614B1 EP0031614B1 (en) 1984-10-24
EP0031614B2 true EP0031614B2 (en) 1990-07-18

Family

ID=22300906

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19800201181 Expired EP0031614B2 (en) 1979-12-17 1980-12-09 Curved array of sequenced ultrasound transducers

Country Status (5)

Country Link
EP (1) EP0031614B2 (enrdf_load_stackoverflow)
JP (1) JPS56103598A (enrdf_load_stackoverflow)
CA (1) CA1152729A (enrdf_load_stackoverflow)
DE (1) DE3069525D1 (enrdf_load_stackoverflow)
ES (1) ES497752A0 (enrdf_load_stackoverflow)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102006010009A1 (de) * 2006-03-04 2007-09-13 Intelligendt Systems & Services Gmbh & Co Kg Verfahren zum Herstellen eines Ultraschallprüfkopfes mit einer Ultraschallwandleranordnung mit einer gekrümmten Sende- und Empfangsfläche
US9224938B2 (en) 2011-04-11 2015-12-29 Halliburton Energy Services, Inc. Piezoelectric element and method to remove extraneous vibration modes
WO2024112570A1 (en) * 2022-11-22 2024-05-30 Provisio Medical, Inc. Multifrequency ultrasound measuring systems and methods

Families Citing this family (32)

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JPS57113596U (enrdf_load_stackoverflow) * 1980-12-30 1982-07-14
JPS5887998A (ja) * 1981-11-20 1983-05-25 Hitachi Ltd 超音波探触子の製造方法
JPS5996999U (ja) * 1982-12-21 1984-06-30 横河電機株式会社 超音波アレイトランスデユ−サ
US4523122A (en) * 1983-03-17 1985-06-11 Matsushita Electric Industrial Co., Ltd. Piezoelectric ultrasonic transducers having acoustic impedance-matching layers
JPS59202058A (ja) * 1983-05-02 1984-11-15 Hitachi Medical Corp 超音波検査装置用探触子の製造方法
EP0128049B1 (en) * 1983-06-07 1990-09-12 Matsushita Electric Industrial Co., Ltd. Ultrasonic probe having a backing member
JPS60114239A (ja) * 1983-11-28 1985-06-20 株式会社日立製作所 超音波探触子の製造方法
JPS60192500A (ja) * 1984-03-14 1985-09-30 Nippon Dempa Kogyo Co Ltd マトリツクス・アレ−型超音波探触子及びその製造方法
FR2580286B1 (fr) * 1985-04-12 1987-05-22 Sintra Materiau anechoique allege
FR2614747B1 (fr) * 1987-04-28 1989-07-28 Dory Jacques Generateur d'impulsions elastiques ayant une forme d'onde predeterminee desiree et son application au traitement ou au diagnostic medical
DK5392A (da) * 1992-01-17 1993-07-18 Reson System As Sonarudstyr for maritimt miljoe
US5423220A (en) * 1993-01-29 1995-06-13 Parallel Design Ultrasonic transducer array and manufacturing method thereof
KR0165516B1 (ko) * 1996-02-26 1999-05-01 김광호 진동 검출 센서
US6337465B1 (en) * 1999-03-09 2002-01-08 Mide Technology Corp. Laser machining of electroactive ceramics
US6618620B1 (en) 2000-11-28 2003-09-09 Txsonics Ltd. Apparatus for controlling thermal dosing in an thermal treatment system
US6632179B2 (en) * 2001-07-31 2003-10-14 Koninklijke Philips Electronics N.V. Acoustic imaging system with non-focusing lens
JP3856380B2 (ja) 2002-04-26 2006-12-13 テイカ株式会社 コンポジット圧電振動子およびその製造方法
US7611462B2 (en) * 2003-05-22 2009-11-03 Insightec-Image Guided Treatment Ltd. Acoustic beam forming in phased arrays including large numbers of transducer elements
US8409099B2 (en) 2004-08-26 2013-04-02 Insightec Ltd. Focused ultrasound system for surrounding a body tissue mass and treatment method
US20070016039A1 (en) 2005-06-21 2007-01-18 Insightec-Image Guided Treatment Ltd. Controlled, non-linear focused ultrasound treatment
US8235901B2 (en) 2006-04-26 2012-08-07 Insightec, Ltd. Focused ultrasound system with far field tail suppression
WO2011045669A2 (en) 2009-10-14 2011-04-21 Insightec Ltd. Mapping ultrasound transducers
US9852727B2 (en) 2010-04-28 2017-12-26 Insightec, Ltd. Multi-segment ultrasound transducers
US20130079621A1 (en) * 2010-05-05 2013-03-28 Technion Research & Development Foundation Ltd. Method and system of operating a multi focused acoustic wave source
US9981148B2 (en) 2010-10-22 2018-05-29 Insightec, Ltd. Adaptive active cooling during focused ultrasound treatment
HK1201429A1 (en) 2011-10-17 2015-09-04 Butterfly Network Inc. Transmissive imaging and related apparatus and methods
US9667889B2 (en) 2013-04-03 2017-05-30 Butterfly Network, Inc. Portable electronic devices with integrated imaging capabilities
DE102013211627A1 (de) * 2013-06-20 2014-12-24 Robert Bosch Gmbh Elektroakustischer Wandler
FR3027827B1 (fr) * 2014-11-03 2020-01-31 Imasonic Transducteur ultrasonore a couche de microballons
GB2557345B (en) 2016-12-08 2021-10-13 Bae Systems Plc MIMO communication system and data link
GB2565159B (en) * 2017-07-19 2021-12-01 Bae Systems Plc Electroacoustic transducer
CN110646802B (zh) * 2019-09-26 2022-08-02 哈尔滨工程大学 一种水听器镜像对称弧型阵及其布置方法

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JPS52131676A (en) * 1976-04-27 1977-11-04 Tokyo Shibaura Electric Co Probe for ultrasonic diagnostic device

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102006010009A1 (de) * 2006-03-04 2007-09-13 Intelligendt Systems & Services Gmbh & Co Kg Verfahren zum Herstellen eines Ultraschallprüfkopfes mit einer Ultraschallwandleranordnung mit einer gekrümmten Sende- und Empfangsfläche
US9224938B2 (en) 2011-04-11 2015-12-29 Halliburton Energy Services, Inc. Piezoelectric element and method to remove extraneous vibration modes
WO2024112570A1 (en) * 2022-11-22 2024-05-30 Provisio Medical, Inc. Multifrequency ultrasound measuring systems and methods

Also Published As

Publication number Publication date
JPS56103598A (en) 1981-08-18
ES8107014A1 (es) 1981-09-16
DE3069525D1 (en) 1984-11-29
EP0031614B1 (en) 1984-10-24
CA1152729A (en) 1983-08-30
ES497752A0 (es) 1981-09-16
JPH0452040B2 (enrdf_load_stackoverflow) 1992-08-20
EP0031614A1 (en) 1981-07-08

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