US3831434A - Methods and apparatus for image display of sound waves and utilizations thereof - Google Patents

Methods and apparatus for image display of sound waves and utilizations thereof Download PDF

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Publication number
US3831434A
US3831434A US00237404A US23740472A US3831434A US 3831434 A US3831434 A US 3831434A US 00237404 A US00237404 A US 00237404A US 23740472 A US23740472 A US 23740472A US 3831434 A US3831434 A US 3831434A
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cell
acoustic
image
waves
liquid crystal
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US00237404A
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P Greguss
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Vari-Light Corp
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Vari-Light Corp
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Priority to US00237404A priority Critical patent/US3831434A/en
Priority to DE2313738A priority patent/DE2313738A1/de
Priority to CA166,774A priority patent/CA1002172A/en
Priority to GB1418573A priority patent/GB1433623A/en
Priority to JP48033381A priority patent/JPS498261A/ja
Priority to FR7310591A priority patent/FR2177410A5/fr
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01H—MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES
    • G01H9/00—Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by using radiation-sensitive means, e.g. optical means
    • G01H9/002—Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by using radiation-sensitive means, e.g. optical means for representing acoustic field distribution
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
    • G03H3/00—Holographic processes or apparatus using ultrasonic, sonic or infrasonic waves for obtaining holograms; Processes or apparatus for obtaining an optical image from them

Definitions

  • a device employing a piezo-optic cell having a thin layer of aligned liquid crystals which is illuminated by polarized light and viewed through a polarized analyzer to give a real-time visual image in color of the acoustic wave pattern incident thereon.
  • the acoustic wave pattern is typically an acoustic image of an insonified object such that the resulting device is useful in non-destructive testing for industry and medicine.
  • the acoustic wave pattern can also be the human [56] References Cited voice (helpful in teaching speech to the deaf) and UNITED STATES PATENTS music (for pleasurable and informative visualization of 3,597,043 8/1971 Dreyer 350/149 the musical sound).
  • a reference acoustic ,5 8/1971 Cohen eta! R wave this device may be utilized to obtain a holo- 3,700,805 10/1972 Hanlon 178/73 D graphic image 3.707.323 12/1972 Kessler et a1.
  • the present invention relates to the general field of mechanical-to-optical wave form conversion which finds particular application in the insonification of objects with conversion of the resulting acoustic image to a visual display.
  • Such use with ultrasonography and the like has considerable potential for many uses including non-destructive testing and diagnostics.
  • it should be recognized that much of the exemplification of this invention will be in terms of acoustical waves including ultrasonics through infrasonics, but in its broader aspects is applicable to mechanical waves of all frequencies, in general.
  • the acoustic signal emerging from the insonified specimen could be detected by a scanning acoustic receiver.
  • the latter is in the form of a transducer which converts the acoustic signal into an electrical signal.
  • a holographic transparency is then recorded and reduced for optical reconstruction of the acoustic image.
  • this technique still has many of the drawbacks of the applicants aforementioned earlier developments. Although it achieved a greater sensitivity, its lack of a real-time image makes it completely unsuitable for biological-medical applications and the like.
  • these advantages can be obtained by the utilization of a piezo-optic cell of the type described in US. Pat. No. 3,597,043, issued Aug. 3, 1971 (the description of which is incorporated herein by reference) with a sufficiently thin liquid crystal layer, effectively coupled to the source of an acoustic wave pattern emanating from the object to be observed, illuminated by polarized light passing through the cell and viewed through a relatively rotatable polarizer (or a functional equivalent).
  • a dichroic liquid crystal compound is used, the liquid crystal may serve as the first polarizer and only one additional polarizing filter is needed, as an analyzer.
  • the optical element of the aforementioned patent is a piezo-optic cell which functions as a recording media for converting mechanical waves into corresponding visible colored patterns.
  • the patentee recognized the response of his cell to acoustic energy, there is no teaching nor recognition that such a cell would be useful in obtaining a good quality visual image of an insonified object.
  • applicant in connection with his decades of work on developing acoustical-to-optical converters recognized the possibility of adapting the patentees cell to function as an effective acoustical-to-optical converter having sufficient sensitivity and resolution to give the desired visual image of the insonified object.
  • This cell used for this purpose is currently referred to in the art as AOCC (Acousticalto-Optical Converter Cell).
  • the applicant suggests the following theory.
  • the nematic liquid crystal molecules are sandwiched in a thin layer between two glass plates.
  • the aforementioned patent indicates that when its lubricant is used on "the surface of one of the plates in contact with the liquid crystal film such substance will remove any effect of surface orientation of the supporting plates.
  • the liquid crystals in said film may be characterized as being substantially in their free state.
  • the birefrigence is uniform across the field.
  • These disorientations may function as a diffraction grating, the interaction of the line spacings of which functions to help re-create the acoustic image in a correspondingly sized visual image causing the piezooptic cell to function as a wave-length converter.
  • the piezooptical cell can be considered to act partly as a volume hologram and so as a hologram which can be recon structed with white light. That this is the case is illustrated by the floating E experiment discussed below.
  • the acoustic hologram can be created in the usual manner by using two separate acoustic transducers, one supplying the reference wavefront and the other insonifying the object to supply the object wavefront.
  • the same effect can be achieved by splitting the beam from one acoustic transducer into two separate reference and object beams.
  • a single acoustic transducer can also be used by having its beam incident on the piezo-optic cell at a sufficiently acute angle to have a traveling wave established in the cell. Experiments indicate that a practical limit at present on the viewing angle is fi0 (this is not to be confused with the angle of incidence of the ultrasonic beam on the cell, just mentioned).
  • the frequency range for this invention is the whole acoustic spectrum.
  • varying .the frequency one changes the color patterns of the image created at a given polarizer setting. It may thereby be possible to emphasize different features of the image by more effective color contrasting (or alternatively merely by adjusting the polarizer setting). Similar results can be achieved by use of multiple selected frequencies.
  • Match the frequencies (or the wave length) with the structure of the object being analyzed e.g., soft tissue or foundry castings
  • Image size can also apparently be somewhat controlled by altering various factors including the coupling media, shape of the cell, etc.
  • this invention may have the following more specific utilizations.
  • the visualized acoustic image developed in the transparent piezo-optic cell may simultaneously have projected thereon a super-imposed optical image.
  • the two optic and sonic-derived visual images related as to size and content so that one would view in essence a double exposure indicating the exterior and outline of the object being viewed and at the same time an x-ray like visualization of the internal structure of the object.
  • this invention could find particular application in the medical examination of soft tissue, tumors and the like.
  • the differentiation of tumors from surrounding soft materials is particularly useful since sound waves react to such materials in a manner different from x-rays and therefore can often differentiate to a better degree.
  • the invention can also be used as well in diagnostics as in nondestructive testing, in analyzing reflections within such structures or transsonification of these structures and the tissue therebeyond.
  • this invention can find application as an underwater radar display useful for submarines, in oceanography, and in night-time or deep-skin-diving.
  • this invention could be utilized as a visual aid for deaf persons.
  • This invention it would be possible to identify and teach visual display patterns of the various sounds. These patterns could probably be learned within a year or so in much the same way that a written foreign language is learned.
  • One problem is that the wave lengths of audible sound are too large to be displayed on a piezo-optic cell of convenient dimensions so that such a cell is not suitable for direct visualization of the characteristic sound patterns.
  • the display could be formed thereby of a convenient size. This can be achieved for example by using a ceramic transducer with a fundamental frequency identical to the carrier frequency of an FM radio and driving it with an FM signal.
  • the field pattern of this ceramic transducer visualized by the piezo-optic cell would yield a recognizable pattern of the audible sound. Since this pattern would be in color, it would be easier to memorize and therefore to learn how to hear by seeing.
  • An additional feature could be to use two ceramic transducers at right angle in a stereophonic manner and obtain recognizable interference patterns.
  • the utility of this invention can be further expanded by utilizing optical and/or sonic lenses and even fiber optics. These can be used to focus or otherwise alter the sonic image prior to conversion or to better visualize the optical image created after conversion.
  • the piezo-optic cells could also have multiple liquid crystal layers in depth by having one or more very thin glass sheets (or the like) interleaved between said layers. This would give a greater display depth and yet not adversely affect the normal alignment of the liquid crystals by having the spacing forming each individual liquid crystal layer being too large.
  • a thin layer of nematic liquid crystal between two glass plates there is a thin layer of nematic liquid crystal between two glass plates, the inner surfaces of which plates have been coated with a thin layer (probably monomolecular) of lecithin or compounds with similar effect.
  • This layer thickness of liquid crystals follows typically the following equation FH /C K (a constant) which F is frequency and which K depends upon the liquid crystal material used.
  • H is the thickness of the liquid crystal layers and C is the sound velocity in the liquid crystal layer said layer is typically about 0.001 inches thick.
  • the glass facing the sonic generator is about 1/16 of an inch thick.
  • the opposite sheet of glass is about one-quarter of an inch thick.
  • the sandwich of glass and liquid crystals are preferably sealed and positioned along the edges by an epoxy cement.
  • the overall size of these cells has been approximately two to ten inches, but in actual fact is limited at the lower end merely by aperture considerations and at the upper end by the physical problems of maintaining the inter-glass spacing sufficient to retain the required alignment of the liquid crystals therein. If the sizes get too large there is a gravitational tendency of the glass to sag in the horizontal position or of the weight of the liquid crystal solution to bulge the glass, if the cell is held in the vertical position.
  • liquid crystal thicker layer is no more than 0.010 inches thick, because a layer tends to become translucent.
  • this invention can utilize a piezo-optic cell of the type described in FIG. 3 of the aforementioned patent where one of the sides of the cell has a reflecting surface. It is possible that the glass plate on the reflecting surface side could be replaced by a polished metal provided the alignment of the liquid crystals is not thereby adversely affected.
  • the ultrasonic energy be pulsed and the visual image thereof be viewed with strobescopic light to thereby obtain a holographic cross-sectional image of the solid object being trans-sonified at a given depth thereof.
  • the sound beam be scanned to give an electrical image that can be transmitted by radio and, can be reconstructed by a sonic transducer to give a sonic beam incident on a pieZo-optic cell at a remote location to give a very thin holographic television display.
  • FIG. 1 is a schematic plan view of a device embodying the present invention.
  • FIG. 2 is a schematic sectional view of a piezo-optic cell.
  • FIG. 3 is a schematic plan view (partially exploded for clarity) of an alternative embodiment of the present invention illustrating a solid instead of a liquid coupling.
  • FIG. 4 is a schematic plan view (partially exploded for clarity) of a third embodiment of the present invention illustrating the use of a reflecting piezo-optic cell.
  • FIG. 5 is a schematic plan view of a fourth embodiment of the present invention illustrating that the direct line up of the ultrasonic generator, the object to be viewed, and the piezo-optic cell is not required, but can be achieved by reflection.
  • FIG. 6 is a schematic side elevational view of a fifth embodiment of the present invention illustrating the creation of an image from an ultrasonic generator coupled by solid contact between the object and the edge of the piezo-optic plate.
  • a box 10 conveniently constructed of a clear acrylic plastic is filled with water 12 which has immersed therein at one end of the box 10 a piezo-optic cell 14 and opposite therefrom an ultrasonic generator 16.
  • the water 12 preferably has a small amount of wetting agent such as l/lO percent Aerosal OT to give good coupling between the generator 16 and the cell 14 so as to carry the sonic waves therebetween with little loss.
  • the ultrasonic generator 16 is a l to 3 MHz piezo-electric transducer.
  • the generator 16 is directed at the object 18 which is to be transsonifled and therebeyond at the cell 14.
  • the object 18 is here illustrated as a metal cube having a hole 20 drilled therein.
  • a linear polarizer 22 At the end of the box 10 adjacent to generator 16 is a linear polarizer 22, a difuser 24, and a light source 26 for creating polarized light incident on the back of the piezo-optic cell 14.
  • the visually converted ultrasonic image of the object 18 and its hole 20 appears on the flat surface of the cell 14 when viewed through a polarizing filter 28. It will be appreciated that the relative positioning of these various elements can vary to a large degree and still give the desired effect within the scope of the present invention.
  • the cell 14 could form the front of the box 12 and be integrally constructed therewith and the front plate 30 of the cell 14 could have a polarizing surface (provided that the polarized light incident thereon is rotated at a desirable angle or is rotatable with respect thereto so as to achieve any desired angle). As discussed in the aforementioned patent, these two polarizers 22 and 28 need not be crossed.
  • the piezo-optic cell 14 has a thin plate of glass 32 which should function as an acoustic window. Therefore, as previously indicated, it would preferably have a thickness governed by the previously discussed equation.
  • the liquid crystal layer 34 is apparently aligned by the effect of the lecithin layers 36 and 38 on either side thereof.
  • the function of this lecithin, or its equivalent, is discussed in the aforementioned patent as being a lubricant, but more properly is probably a positive orienting means in that one end of the lecithin molecule is attracted to the polarity of the glass and the other end of the lecithin molecule is attracted to the liquid crystal layer, thereby counteracting the effect of surface orientation of the glass.
  • the plates 30 and 32 are fixedin spaced relation by epoxy cement 40.
  • the water 12 preferably is degassed and may have additives to enhance its coupling function.
  • Alternative liquid couplers such as glycerine can also be used.
  • the box 10 can be constructed as an anechoic liquid chamber for the coupler 12 to eliminate any ultrasonic reflections impinging upon the piezo-optic cell 14 and thereby give a clearer image thereon.
  • Impedance matching layers may be put on the glass surface to reduce the reflections of the glass surface to the piezooptic cell.
  • a good alternative coupler is'the solid object 18 itself in direct contact with the generator 16 and the cell 14, as in FIGS. 3 and 4.
  • the ultrasonic generator 16 is put in direct contact with the solid object 18 which in turn is in effective contact with the cell 14 through the light source 26 and the polarizer 22.
  • the latter two objects will have to transmit ultrasonic waves well.
  • Such flat light sources might be created by electroluminescence, phosphorescence, or perhaps even difusing plate sidelights.
  • any one or more of the individual elements of the inventive device may be incorporated as a part of one or more of the other items so long as the necessary function is achieved.
  • the device of FIG. 4 is similar to FIG. 3 except that only one polarizer 28 is used and the light source 26 is on the same side as the cell 14 as the viewer 17, physically separated from the coupling between the sound generator 16, the object 18, and the cell 14.
  • the light from the source 26 is polarized as it passes through polarizer 28, falls upon the reflecting mirror 42 positioned beyond the liquid crystal layer 34, and is reflected back through polarizer 28 (after having been acted upon by the birefringence of the layer 34) to give the desired image to the viewer 17.
  • the ultrasonic radiation of the piezo-optic cell can be at an angle as well as perpendicular to the surface.
  • acoustical energy of about 0.5 watts per square inch is needed to create images on the piezo-optic cells made with lecithin and nematic liquid crystal MBBA in accordance with the aforementioned patent disclosure.
  • considerably less energy can be used with efficient systems according to the present invention.
  • the object 18 schematically indicated in FIG. 5 is a bone specimen.
  • the sonic waves from the sonic generator 16 are reflected off the back of cell 14 onto the specimen l8 and back onto the cell 14.
  • a patterned image was viewed on the cell 14 depicting the internal structure of the scull bone.
  • a sonic generator 16 with a right angle prism shaped head acting as the object 18 has engraved in one flat side thereof a hole 20 in the shape of a flat E.
  • the object 18 was placed in direct contact with the edge of the piezo-optic cell 14 and the viewer located at 17 could see the floating" image of the engraved E in the cell 14.
  • the object to be viewed need not be a solid, but can be liquids with different densities or even can be a virtual object such as music.
  • a mechanical wave-optical converter imaging device for visualizing a mechanical wave pattern image, for example of an object, comprising a piezo-optic visual display cell, having a thin layer of aligned liquid crystals, means for polarized transillumination of said cell, a mechanical wave image generating source oriented to be incident on said cell, and analyzing means for observing the changes in birefringence occasioned by the action of the mechanical waves in a patterned image on the liquid crystal layer of the piezo-optic cell.
  • a device as claimed in claim 1 further comprising coupling means for effectively coupling said cell, object and source efficiently to transmit said mechanical waves therebetween, wherein said mechanical waves are acoustic waves, said source is an acoustic transducer oriented to impinge upon said object so as to cause a wave-form image thereof to be incident on said cell, and said liquid crystal layer has a thickness small enough to view said image.
  • a device as claimed in claim 3, wherein the mechanical wave generating source is an acoustic transducer positioned to trans-sonify the object to be incident on said cell.
  • a device as claimed in claim 2, wherein the mechanical wave generating source is an acoustic transducer positioned to insonify said cell with acoustic waves reflected from said object.
  • the mechanical wave generating source is an acoustic transducer positioned to form a solid coupling to a face of said cell.
  • a device as claimed in claim 8 comprising a light source positioned to be incident on the viewing side of said cell through the polarized analyzing means, and a mirror on the opposing cell face which is in contact with said coupling means whereby the light source, analyzer and mirror combine to form said polarizing means.
  • a device as claimed in claim 3, wherein the mechanical wave generating source is an acoustic transducer positioned to form a solid coupling to an edge of said cell.
  • a device as claimed in claim 3 for creating visualized acoustic holograms comprising a means for generating and directing reference acoustic waves on said cell in coherence and overlap with said object acoustic waves.
  • a device as claimed in claim 3 wherein the thickness of said liquid crystal layer is governed by the following equation FH /C less than or equal to K, wherein H is the thickness of the liquid crystal layer, C is the velocity of the acoustic wave in the crystal layer, F is the frequency and K is a constant for the given device.
  • a method of forming a real-time visual image of an acoustic wave pattern image of objects comprising the steps of treating at least one interface surface formed of a layer of liquid crystals and of its surrounding environment with a lubricant to reduce the surface orientation of the environment on said liquid crystals, insonifying the objects to be viewed and directing the acoustic wave pattern image thus formed focused onto a layer of liquid crystals the thickness of which is small enough to assure clarity of the resulting visual image, transilluminating the layer with polarized light and viewing the thus illuminated layer with an analyzer.
  • a method as claimed in claim 15 for creating visualized acoustic holograms comprising generating and directing reference acoustic waves on said cell in coherence and overlap with said object acoustic waves.
  • a method according to claim 15 comprising using said method for acoustic radar by reflective insonification of said objects.
  • Claim 14 '2 should be 3-.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Holo Graphy (AREA)
  • Liquid Crystal (AREA)
  • Stereophonic System (AREA)
  • Devices For Indicating Variable Information By Combining Individual Elements (AREA)
  • Ultra Sonic Daignosis Equipment (AREA)
US00237404A 1972-03-23 1972-03-23 Methods and apparatus for image display of sound waves and utilizations thereof Expired - Lifetime US3831434A (en)

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Application Number Priority Date Filing Date Title
US00237404A US3831434A (en) 1972-03-23 1972-03-23 Methods and apparatus for image display of sound waves and utilizations thereof
DE2313738A DE2313738A1 (de) 1972-03-23 1973-03-20 Verfahren und vorrichtung zum sichtbarmachen von schallwellen
CA166,774A CA1002172A (en) 1972-03-23 1973-03-22 Methods and apparatus for image display or sound waves and utilization thereof
GB1418573A GB1433623A (en) 1972-03-23 1973-03-23 Method and device for generating visual patterns
JP48033381A JPS498261A (enrdf_load_stackoverflow) 1972-03-23 1973-03-23
FR7310591A FR2177410A5 (enrdf_load_stackoverflow) 1972-03-23 1973-03-23

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US00237404A US3831434A (en) 1972-03-23 1972-03-23 Methods and apparatus for image display of sound waves and utilizations thereof

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JP (1) JPS498261A (enrdf_load_stackoverflow)
CA (1) CA1002172A (enrdf_load_stackoverflow)
DE (1) DE2313738A1 (enrdf_load_stackoverflow)
FR (1) FR2177410A5 (enrdf_load_stackoverflow)
GB (1) GB1433623A (enrdf_load_stackoverflow)

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3991606A (en) * 1974-11-08 1976-11-16 Minnesota Mining And Manufacturing Company Apparatus and method for converting mechanical wave energy to optical energy
US4077253A (en) * 1973-06-01 1978-03-07 Grisell Ronald D Apparatus and method for the imaging of the internal structure of a three-dimensional solid and/or liquid object
US4338821A (en) * 1978-10-13 1982-07-13 Dion Jean Luc Liquid crystal cell for acoustical imaging
US4379408A (en) * 1981-01-12 1983-04-12 Raj Technology Partnership Liquid crystal technique for examining internal structures
EP0113941A1 (en) * 1983-01-17 1984-07-25 Raj Technology Partnership Liquid crystal acousto-optical detector cell
EP0101189A3 (en) * 1982-07-20 1984-10-17 Raj Technology Partnership Non-destructive testing system employing a liquid crystal detector cell
US4679436A (en) * 1986-08-05 1987-07-14 Raj Technology, Inc. Reciprocating method and apparatus for producing uniform ultrasonic field for use in liquid crystal based acoustical imaging
US4788865A (en) * 1986-11-26 1988-12-06 Raj Technology, Inc. Construction of liquid crystal cell for acoustic imaging
US5771041A (en) * 1994-06-03 1998-06-23 Apple Computer, Inc. System for producing directional sound in computer based virtual environment
WO1999015863A1 (en) * 1997-09-24 1999-04-01 3Dv Systems, Ltd. Acoustical imaging system
US6049411A (en) * 1998-10-14 2000-04-11 Santec Systems Inc Optical imager for birefringent detector acoustic imaging systems
US6321023B1 (en) 2000-06-20 2001-11-20 Honghui Wang Serial imager for birefringent detector acoustic imaging systems
ES2245203A1 (es) * 2003-12-02 2005-12-16 Universidad De La Laguna Transductor acustico optico electronico de visualizacion de sonidos para personas sordas.
US9786204B2 (en) 2013-11-25 2017-10-10 The University Of Scranton Visualizing sound with an electro-optical eardrum
CN112880803A (zh) * 2021-01-19 2021-06-01 业成科技（成都）有限公司 光学环境振荡侦测系统及应用其的光学量测方法
GB2610588A (en) * 2021-09-08 2023-03-15 Univ Warwick Acoustic field visualisation

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JPS5678819A (en) * 1979-11-30 1981-06-29 Seiko Epson Corp Liquid-crystal device
US4393712A (en) * 1981-09-08 1983-07-19 Raj Technology Partnership Portable liquid crystal testing device
JPS61189277A (ja) * 1985-02-15 1986-08-22 Idemitsu Kosan Co Ltd トリアジン誘導体，その製造方法およびそれを有効成分とする除草剤
JPS6341825A (ja) * 1986-08-06 1988-02-23 Yamamoto Kogaku Kk 調光フイルタ−
CN110133879B (zh) * 2019-04-25 2022-12-09 福建师范大学 一种提高超声调制光成像深度的装置和方法

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US3599477A (en) * 1969-05-14 1971-08-17 Lockheed Aircraft Corp Apparatus for converting acoustic energy into a visible image
US3700805A (en) * 1971-08-26 1972-10-24 Thomas F Hanlon Black-and-white image control by ultrasonic modulation of nematic liquid crystals
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GB1194544A (en) * 1966-08-03 1970-06-10 Battelle Development Corp Liquid Crystal Detector
US3597043A (en) * 1969-05-02 1971-08-03 Polacoat Inc Nematic liquid crystal optical elements
US3599477A (en) * 1969-05-14 1971-08-17 Lockheed Aircraft Corp Apparatus for converting acoustic energy into a visible image
US3707323A (en) * 1970-11-06 1972-12-26 Zenith Radio Corp Liquid crystal devices and systems for ultrasonic imaging
US3700805A (en) * 1971-08-26 1972-10-24 Thomas F Hanlon Black-and-white image control by ultrasonic modulation of nematic liquid crystals

Cited By (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4077253A (en) * 1973-06-01 1978-03-07 Grisell Ronald D Apparatus and method for the imaging of the internal structure of a three-dimensional solid and/or liquid object
US3991606A (en) * 1974-11-08 1976-11-16 Minnesota Mining And Manufacturing Company Apparatus and method for converting mechanical wave energy to optical energy
US4338821A (en) * 1978-10-13 1982-07-13 Dion Jean Luc Liquid crystal cell for acoustical imaging
US4379408A (en) * 1981-01-12 1983-04-12 Raj Technology Partnership Liquid crystal technique for examining internal structures
US4506550A (en) * 1981-02-06 1985-03-26 Raj Technology Partnership Non-destructive testing system employing a liquid crystal detector cell
EP0101189A3 (en) * 1982-07-20 1984-10-17 Raj Technology Partnership Non-destructive testing system employing a liquid crystal detector cell
AU567880B2 (en) * 1982-07-20 1987-12-10 Sandhu, J.S. Liquid crystal detector cell for ultrasonic imaging.
EP0113941A1 (en) * 1983-01-17 1984-07-25 Raj Technology Partnership Liquid crystal acousto-optical detector cell
US4679436A (en) * 1986-08-05 1987-07-14 Raj Technology, Inc. Reciprocating method and apparatus for producing uniform ultrasonic field for use in liquid crystal based acoustical imaging
US4788865A (en) * 1986-11-26 1988-12-06 Raj Technology, Inc. Construction of liquid crystal cell for acoustic imaging
US5771041A (en) * 1994-06-03 1998-06-23 Apple Computer, Inc. System for producing directional sound in computer based virtual environment
WO1999015863A1 (en) * 1997-09-24 1999-04-01 3Dv Systems, Ltd. Acoustical imaging system
US6049411A (en) * 1998-10-14 2000-04-11 Santec Systems Inc Optical imager for birefringent detector acoustic imaging systems
US6321023B1 (en) 2000-06-20 2001-11-20 Honghui Wang Serial imager for birefringent detector acoustic imaging systems
ES2245203A1 (es) * 2003-12-02 2005-12-16 Universidad De La Laguna Transductor acustico optico electronico de visualizacion de sonidos para personas sordas.
ES2245203B2 (es) * 2003-12-02 2007-10-16 Universidad De La Laguna Transductor acustico optico electronico de visualizacion de sonidos para personas sordas.
US9786204B2 (en) 2013-11-25 2017-10-10 The University Of Scranton Visualizing sound with an electro-optical eardrum
CN112880803A (zh) * 2021-01-19 2021-06-01 业成科技（成都）有限公司 光学环境振荡侦测系统及应用其的光学量测方法
CN112880803B (zh) * 2021-01-19 2022-11-22 业成科技（成都）有限公司 光学环境振荡侦测系统及应用其的光学量测方法
GB2610588A (en) * 2021-09-08 2023-03-15 Univ Warwick Acoustic field visualisation
WO2023037108A1 (en) * 2021-09-08 2023-03-16 The University Of Warwick Acoustic field visualisation

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JPS498261A (enrdf_load_stackoverflow) 1974-01-24
GB1433623A (en) 1976-04-28
FR2177410A5 (enrdf_load_stackoverflow) 1973-11-02
CA1002172A (en) 1976-12-21
DE2313738A1 (de) 1973-09-27

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