US3541848A - Acoustical imaging system - Google Patents

Acoustical imaging system Download PDF

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Publication number
US3541848A
US3541848A US770928A US3541848DA US3541848A US 3541848 A US3541848 A US 3541848A US 770928 A US770928 A US 770928A US 3541848D A US3541848D A US 3541848DA US 3541848 A US3541848 A US 3541848A
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Prior art keywords
energy
detector
acoustical
waveguide
medium
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Expired - Lifetime
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US770928A
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English (en)
Inventor
Frederick L Thurstone
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Warner Lambert Technologies Inc
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American Optical Corp
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Assigned to WARNER LAMBERT TECHNOLOGIES, INC., A CORP OF TX. reassignment WARNER LAMBERT TECHNOLOGIES, INC., A CORP OF TX. ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: WARNER LAMBERT COMPANY
Assigned to WARNER LAMBERT COMPANY, A CORP. OF DEL. reassignment WARNER LAMBERT COMPANY, A CORP. OF DEL. ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: AMERICAN OPTICAL CORPORATION,
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J31/00—Cathode ray tubes; Electron beam tubes
    • H01J31/08—Cathode ray tubes; Electron beam tubes having a screen on or from which an image or pattern is formed, picked up, converted, or stored
    • H01J31/495—Pick-up tubes adapted for an input of sonic, ultrasonic, or mechanical vibrations and having an electric output
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01H—MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES
    • G01H3/00—Measuring characteristics of vibrations by using a detector in a fluid
    • G01H3/10—Amplitude; Power
    • G01H3/12—Amplitude; Power by electric means
    • G01H3/125—Amplitude; Power by electric means for representing acoustic field distribution
    • 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
    • G01N29/2437—Piezoelectric probes
    • G01N29/2443—Quartz crystal probes
    • 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
    • G01N29/2462—Probes with waveguides, e.g. SAW devices

Definitions

  • ACOUSTICAL IMAGING SYSTEM Filed Oct. 28, 1968 32 ELECTRON M [8 su/v V I NVENTOR. FREDP/C/f L. THURS TONE ATTORNEY United States Patent Oihce 3,541,848 Patented Nov. 24, 1970 US. Cl. 73-67.5 Claims ABSTRACT OF THE DISCLOSURE
  • a system for electroacoustically producing images of objects placed in an ultrasound transmitting medium which is coupled to a piezoelectric transducer.
  • the coupling includes a sonic waveguide for accepting acoustical energy thorugh a large angle of incidence and directing the energy to the transducer at a normal angle of incidence.
  • the critical angle of incidence for total reflection of acoustical energy may be quite small.
  • the effective aperture or output of the system When used for imaging purposes is seriously restricted by a substantial loss of sonic energy by reflection from the detector back into the coupling medium.
  • the present invention overcomes this restriction With coupling which greatly increases the angle through which acoustic energy will be transmitted through the coupling interface in a system of the aforesaid type.
  • the acoustic energy acceptance angle at the interface of a detector medium e.g., piezoelectric plate
  • coupling medium e.g., water
  • the waveguide is placed immediately adjacent to the detector plate in the coupling medium and comprises a rigid matrix of acoustical waveguides each in the form of a hollow channel extending right angularly toward the detector plate.
  • Each channel is of a diametral size in the order of a wavelength of the acoustic energy applied to the image producing system so that a single mode piston type propagation of acoustic energy will take place axially thereof and accordingly be received by the detector plate at a zero angle of incidence.
  • Such energy propagation will be excited at the entrance aperture of each channel through a large angle of incidence of incident acoustical energy and the channel, in turn, will deliver this energy only along its axial direction,
  • FIG. 1 diagrammatically illustrates an acoustical image producing system which is exemplary of a type to which the improvement of this invention is applicable;
  • FIG. 2 is a greatly enlarged fragmentary cross-sectional view of a portion of the system of FIG. 1;
  • FIG. 3 is a greatly enlarged fragmentary cross-sectional view similiar to FIG. 2 wherein details of the present inventive concept are illustrated.
  • FIG. 1 diagrammatically illustrates an electroacoustical image producing cell 10 having an electron image converter tube 12 associated therewith.
  • This unit is exemplary of a type of system to which the present inventive concept is applicable.
  • Cell 10 includes tank 14 having a window at one end in the form of a piezoelectric image transducer (e.g., a quartz plate) which will be referred to hereinafter as image detector 16.
  • image detector 16 At the opposite end of tank 14 is ultrasound generator 18 preferably in the form of a crystal transducer capable of producing acoustic energy of frequencies in the order of from 1. to 20 megacycles per second,
  • Tank 14 is filled to a level above image detector 16 with an ultrasound transmitting coupling medium 20 (e.g., water) which transmits acoustic energy from generator 18 to detector 16.
  • an ultrasound transmitting coupling medium 20 e.g., water
  • An object 22 intended to be nondestructively examined by ultrasonic imaging is immersed in the liquid coupling medium between generator 18 and detector 16.
  • Object 22 may be an industrial product such as a weldment or the like or an in vivo or excised biological specimen.
  • Sound waves 24 produced by generator 18 in coupling medium 20 which become incident upon object 22 are suppressed, partially absorbed, diiferently refracted and/ or otherwise modified according to the external configuration and/or internal structure or nature of the object during transmittance therethrough.
  • Such sound waves may be considered as image forming waves.
  • Their effect upon detector 16 is to induce electrical charges on surface 26 of piezoelectric detector 16 of values corresponding to the position of incidence and respective sonic pressures applied thereby upon detector 16.
  • the ultrasound field of waves 25 is converted to what may be termed as an electrical image of object 22 located on the piezoelectric surface 26 of detector 16.
  • Image converter tube 12 is illustrative of means which may be employed to convert the aforesaid electrical image into a modulated electrical signal which in turn may be applied to the scanning circuit of a conventional cathode ray tube for visual display of the image.
  • Tube 12 having electron gun 28 scans surface 26 of detector 16 with electron beam 30 whereupon secondary emission electrons produced by the incident scanning beam are modulated by the piezoelectric voltage present on surface 26.
  • the modulated secondary emission electrons 32 are induced by accelerating mesh 34 into electron multiplier 36 from which, through lead 38, the signal may be directed to a cathode ray display tube (not shown).
  • angle 1' represents a critical angle of incidence at which total reflection of acoustic energy takes place and arrows 42 and 44 represent paths of image forming acoustic energy incident upon face 40 at angles larger than the critical angle.
  • This flected back into coupling medium 20, as shown, and acoustic energy is, accordingly, totally internally reflected hack into coupling medium 20, as shown, and fails to excite detector 16.
  • piezoelectric detector 16 is provided with waveguide 46 placed against the detector 16c0upling 20 interface.
  • Waveguide 46 comprises a rigid matrix of hollow channels 48 which are axially right angularly extended toward face 40 of detector 16.
  • the diametral size of each of channels 48 is in the order of a wavelength of the sonic energy produced by generator 18.
  • Each channel 48 is surrounded by a relatively thick wall 50 which gives the waveguide structure sufficient rigidity to be itself nonvibratile in the coupling medium 20.
  • Waveguide 46 may be formed of various metals such as aluminum, copper, brass or steel or of certain glasses and plastics or their equivalents. Preferred materials would be those which would provide the aforesaid rigidity of structure with minimum thicknesses of walls 50 or, in other words, with a maximum number of channels 48 per unit of surface area.
  • the waveguide may be cemented or otherwise attached to surface 40 of detector 16. Alternatively, it may be supported immediately adjacent to surface 40 by suitable brackets or the like (not shown) extending from. the side walls and/or bottom of tank 14 (FIG. 1).
  • Paths 42 and 44 (FIG. 2) of image forming acoustic energy which, as already mentioned, would ordinarly be totally reflected by face 40 of detector 16 are reproduced in FIG. 3 to illustrate the entirely different energy transfer effect produced by waveguide 46.
  • paths 42 and 44 of acoustic energy upon incidence at the entrance aperture of a waveguide channel, induce a single mode piston type propagation of acoustic energy axially thereof as represented by arrows 42a and 44a and by lines 42b and 44b.
  • This energy then being directed right angularly (i.e., flatly and well within the critical angle i of incidence) against face 40 of detector 16 in each case, now excites the detector to produce electrical charges by piezoelectric action on its surface 26 which charges are positionally and quantitatively representative of the image forming acoustic energy propagated along paths 42 and 44 at angles considerably greater than the aforesaid critical angle.
  • Image forming acoustic energy normally being propagated in medium 20 toward detector 16 within the critical i, as represented by arrow 52 (FIG. 3), is, naturally, largely propagated through a particular one or plurality of channels 48 against whose entrance apertures this energy becomes incident.
  • An acoustical imaging system having an acoustic energy transmitting medium of one acoustical impedance interfacially coupled to a transducer medium of a different acoustical impedance and means for generating acoustic energy in said transmitting medium wherein the improvement comprises:
  • an acoustical waveguide positioned at said coupling interface, said waveguide having a number of juxtapositioned energy transmitting channels in a matrix material with each channel having an entrance aperture exposed to said energy transmitting medium for receiving acoustic energy generated in said transmitting medium.
  • transducer is a piezoelectric plate having an acoustic energy receiving face immediately adjacent to which said waveguide is positioned with said channels extending perpendicularly from said face into said energy transmitting medium.
  • An acoustical imaging system wherein the matrix of said waveguide is nonvibratile when subjected to said acoustic energy.
  • An acoustical imaging system wherein said energy transmitting medium is a liquid and an object to be imaged is immersed in said liquid between said acoustic energy generating means and waveguide whereby said generated energy is modified by transmittance through and around said object and is received by said waveguide as image forming acoustic energy.
  • An acoustical imaging system wherein said image forming acoustic energy is received by said waveguide through angles less and greater than the critical angle of incidence for said coupling interface as determined by said acoustical impedances of said transmitting and transducing media and is transmitted through said waveguide channels to said face of said plate at normal angles of incidence for piezoelectric conversion by said plate into electrical image forming energy.

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  • Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Pathology (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)
  • Measurement Of Mechanical Vibrations Or Ultrasonic Waves (AREA)
US770928A 1968-10-28 1968-10-28 Acoustical imaging system Expired - Lifetime US3541848A (en)

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US77092868A 1968-10-28 1968-10-28

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US (1) US3541848A (enrdf_load_stackoverflow)
JP (1) JPS4814271B1 (enrdf_load_stackoverflow)
DE (1) DE1952760A1 (enrdf_load_stackoverflow)
FR (1) FR2022317A1 (enrdf_load_stackoverflow)
GB (1) GB1289507A (enrdf_load_stackoverflow)
NL (1) NL6915721A (enrdf_load_stackoverflow)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3831137A (en) * 1972-04-14 1974-08-20 Us Navy Acousto-optic underwater detector
US3903498A (en) * 1974-02-28 1975-09-02 Us Health Ultrasound imaging system utilizing shaped acoustic matching elements to increase the effective aperture of an acoustic transducer
US20120061901A1 (en) * 2010-09-10 2012-03-15 Kabushiki Kaisha Toshiba Ultrasonic detecting device and sheet handling apparatus comprising ultrasonic detecting device

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2567683B1 (fr) * 1984-07-12 1986-11-14 Commissariat Energie Atomique Dynode a emission secondaire reglable et dispositifs utilisant une telle dynode

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2567407A (en) * 1948-04-23 1951-09-11 Stromberg Carlson Co Electroacoustic transducer
US2580439A (en) * 1949-09-07 1952-01-01 Bell Telephone Labor Inc Directional acoustic system
US2820214A (en) * 1949-05-28 1958-01-14 John P O'neill Sonar transducers
US2899580A (en) * 1959-08-11 Electron tube

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2899580A (en) * 1959-08-11 Electron tube
US2567407A (en) * 1948-04-23 1951-09-11 Stromberg Carlson Co Electroacoustic transducer
US2820214A (en) * 1949-05-28 1958-01-14 John P O'neill Sonar transducers
US2580439A (en) * 1949-09-07 1952-01-01 Bell Telephone Labor Inc Directional acoustic system

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3831137A (en) * 1972-04-14 1974-08-20 Us Navy Acousto-optic underwater detector
US3903498A (en) * 1974-02-28 1975-09-02 Us Health Ultrasound imaging system utilizing shaped acoustic matching elements to increase the effective aperture of an acoustic transducer
US20120061901A1 (en) * 2010-09-10 2012-03-15 Kabushiki Kaisha Toshiba Ultrasonic detecting device and sheet handling apparatus comprising ultrasonic detecting device
CN102401815A (zh) * 2010-09-10 2012-04-04 株式会社东芝 超声波检查装置以及具备该装置的纸张类处理装置

Also Published As

Publication number Publication date
JPS4814271B1 (enrdf_load_stackoverflow) 1973-05-04
DE1952760A1 (de) 1970-04-30
FR2022317A1 (enrdf_load_stackoverflow) 1970-07-31
NL6915721A (enrdf_load_stackoverflow) 1970-05-01
GB1289507A (enrdf_load_stackoverflow) 1972-09-20

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AS Assignment

Owner name: WARNER LAMBERT COMPANY, 201 TABOR ROAD, MORRIS PLA

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:AMERICAN OPTICAL CORPORATION,;REEL/FRAME:004034/0681

Effective date: 19820513

Owner name: WARNER LAMBERT TECHNOLOGIES, INC.; 6373 STEMMONS F

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:WARNER LAMBERT COMPANY;REEL/FRAME:004034/0700

Effective date: 19820514