US3541848A - Acoustical imaging system - Google Patents

Acoustical imaging system Download PDF

Info

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
Authority
US
United States
Prior art keywords
energy
detector
acoustical
waveguide
medium
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 - Lifetime
Application number
US770928A
Inventor
Frederick L Thurstone
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.)
Warner Lambert Technologies Inc
Original Assignee
American Optical Corp
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 American Optical Corp filed Critical American Optical Corp
Application granted granted Critical
Publication of US3541848A publication Critical patent/US3541848A/en
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,
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01JELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J31/00Cathode ray tubes; Electron beam tubes
    • H01J31/08Cathode ray tubes; Electron beam tubes having a screen on or from which an image or pattern is formed, picked up, converted, or stored
    • H01J31/495Pick-up tubes adapted for an input of sonic, ultrasonic, or mechanical vibrations and having an electric output
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01HMEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES
    • G01H3/00Measuring characteristics of vibrations by using a detector in a fluid
    • G01H3/10Amplitude; Power
    • G01H3/12Amplitude; Power by electric means
    • G01H3/125Amplitude; Power by electric means for representing acoustic field distribution
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N29/00Investigating 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
    • G01N29/22Details, e.g. general constructional or apparatus details
    • G01N29/24Probes
    • G01N29/2437Piezoelectric probes
    • G01N29/2443Quartz crystal probes
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N29/00Investigating 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
    • G01N29/22Details, e.g. general constructional or apparatus details
    • G01N29/24Probes
    • G01N29/2462Probes 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.

Landscapes

  • Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Pathology (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Immunology (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)

Description

Nov. 24, 1970 F. L. THURSTONE 3,541,848
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.
BACKGROUND OF THE INVENTION Field of the invention Ultrasound image producing systems.
Description of the prior art A fundamental problem arising in prior art ultrasound image producing systems and, in fact, in any acoustical system involving the transfer of energy from one media to another is the reflection of acoustical energy at the interface between the detecting medium and the coupling medium due to the differing acoustical impedances of the media.
When the ratio of acoustical impedances of the media is high as for example when one medium is a piezoelectric detector such as a quartz plate and the other medium is a liquid such as Water, then the critical angle of incidence for total reflection of acoustical energy may be quite small. Thus, 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.
SUMMARY OF THE INVENTION According to principles of this invention, the acoustic energy acceptance angle at the interface of a detector medium (e.g., piezoelectric plate) and coupling medium (e.g., water) is greatly increased by the provision of a Waveguide structure which will accept energy through a large angle and, in turn, propagate this energy into the detector medium at a normal angle of incidence.
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,
Details of the present invention will be more fully understood by reference to the following detailed description and the accompanying drawing.
DESCRIPTION OF THE DRAWING 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; and
FIG. 3 is a greatly enlarged fragmentary cross-sectional view similiar to FIG. 2 wherein details of the present inventive concept are illustrated.
DESCRIPTION OF THE PREFERRED EMBODIMENTS 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. 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 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, some of which are illustrated by arrows 25, 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. Thus, 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).
The system thus far described is conventional and its operation, though only briefly described hereinabove, would be thoroughly understood by the artisan.
Heretofore, however, the transfer function of acoustical energy to electrical energy by the piezoelectric detector 16 of such a system has been seriously restricted by reflection, back into coupling medium 20', of large amounts of acoustic energy incident upon the receiving face 40 of detector 16.
This is illustrated in FIG. 2 wherein 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.
Angle i has been chosen arbitrarily since it will become apparent that whatever this angle may be, as determined by the relative acoustical impedances of the detecting and coupling media, the present invention deals with the matter of considerably improving the energy transfer function in electroacoustic systems as follows:
-In FIG. 3, 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).
Operation of the acoustic image transducing system with waveguide 46 (FIG. 3) is as follows:
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.
These 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.
From the foregoing it can be seen that acoustic image forming energy incident upon the transducer coupling system of this invention (FIG. 3) at all angles Within and greatly larger than the normal critical angle of incidence for such coupling systems is effectively utilized with the result of considerable and important improvement in the energy transfer function of the system. This, of course, carries through to a corresponding improvement in the conversion to a signal for visual display or recording of acoustic images by whatever means (e.g., tube 12) may be employed to effect such a conversion.
I claim:
1. 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.
2. An acoustical imaging system according to claim 1 wherein said 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.
3. An acoustical imaging system according to claim 2 wherein the matrix of said waveguide is nonvibratile when subjected to said acoustic energy.
4. An acoustical imaging system according to claim 2 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.
5. An acoustical imaging system according to claim 4 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.
References Cited UNITED STATES PATENTS 2,567,407 9/1951 Slaymaker. 2,580,439 1/1952 Kock. 2,820,214 1/1958 ONeil 340-8 2,899,580 8/1959 Dranetz et al.
RICHARD C. QUEISSER, Primary Examiner J. P. BEAUCHAMP, Assistant Examiner US. Cl. X.R.
US770928A 1968-10-28 1968-10-28 Acoustical imaging system Expired - Lifetime US3541848A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US77092868A 1968-10-28 1968-10-28

Publications (1)

Publication Number Publication Date
US3541848A true US3541848A (en) 1970-11-24

Family

ID=25090140

Family Applications (1)

Application Number Title Priority Date Filing Date
US770928A Expired - Lifetime US3541848A (en) 1968-10-28 1968-10-28 Acoustical imaging system

Country Status (6)

Country Link
US (1) US3541848A (en)
JP (1) JPS4814271B1 (en)
DE (1) DE1952760A1 (en)
FR (1) FR2022317A1 (en)
GB (1) GB1289507A (en)
NL (1) NL6915721A (en)

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 (en) * 1984-07-12 1986-11-14 Commissariat Energie Atomique ADJUSTABLE SECONDARY TRANSMISSION DYNODE AND DEVICES USING SUCH 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 (en) * 2010-09-10 2012-04-04 株式会社东芝 Ultrasonic detecting device and sheet handling apparatus comprising the same

Also Published As

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

Similar Documents

Publication Publication Date Title
Kino Acoustic imaging for nondestructive evaluation
US5734588A (en) Bore probe for tube inspection with guided waves and method therefor
US3911730A (en) Ultrasonic transducer probe system
AU697833B2 (en) Ultrasonic inspection
US3898840A (en) Multi-frequency ultrasonic search unit
US4333474A (en) Ultrasonic imaging system
US3780572A (en) Ultrasonic inspection apparatus
US3541848A (en) Acoustical imaging system
US4995260A (en) Nondestructive material characterization
JP3635453B2 (en) Ultrasonic shear wave oblique angle flaw detection method and apparatus
KR101877769B1 (en) Apparatus for hybrid multi-frequency ultrasound phased array imaging
US4492117A (en) Ultrasonic nondestructive test apparatus
US3510833A (en) Frequency conversion imaging system
US3709029A (en) Ultrasonic inspection apapratus
KR20030081533A (en) High-frequency ultrasound measurement of partial layer thickness of thin-walled tubes by a contact method
JPS59151057A (en) Ultrasonic flaw detector
JPS6326344B2 (en)
JPS634142B2 (en)
JPS63186143A (en) Ultrasonic wave probe
JP2978708B2 (en) Composite angle beam probe
JP3023642B2 (en) Insertion depth measurement method for welded pipe joints
JPH01187447A (en) Two-split type vertical probe
JPH05149931A (en) Method and apparatus for measuring sound speed and density
JPS6229957Y2 (en)
JPH0323864B2 (en)

Legal Events

Date Code Title Description
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