Abstract: A first medium having an acousto-optic activity and a second medium are combined to form a net medium having a net acousto-optic activity greater than the acousto-optic activity of the first medium, where the improvement is substantiated via measurements made at specific viewing conditions, and where the second medium can be chosen because it effects at least one of three key properties of the net medium.

Abstract: A product and method uses acousto-optic reflection-active media having an optical reflectivity which changes with changes in acoustic energy intensity interacting with the media to form images of defects in samples when the defects reflect acoustic energy differently from known acoustically reflecting parts of the samples.

Abstract: A product and method uses acousto-optic reflection-active media having an optical reflectivity which changes with changes in acoustic energy intensity interacting with the media to form images of defects in samples when the defects reflect acoustic energy differently from known acoustically reflecting parts of the samples.

Abstract: A computer-readable signal bearing medium (10) has components (11, 21, 31) which act via a data processor (86) in an imaging system having an acoustic energy source (81) and a birefringent detector (84, 70) to record first data (14) from a first portion (61) of an object (60), the first portion attenuating first acoustic energy (12) at least part way to a first attenuation maximum (13, 43) along a first acousto-optic response (41) of the birefringent detector; to record second data (24) from a second portion (62) of the object, the second portion attenuating second acoustic energy (22) at least part way to a second attenuation maximum (23, 53) along a second acousto-optic response (51) of the birefringent detector; combines the data (32), and outputs a result.

Abstract: Light from a collimated light source which is incident on a birefringent detector at a predetermined optimum angle interacts with the birefringent detector and is viewed by an imaging transducer in order to produce an image which shows changes in the birefringence of the birefringent detector caused by acoustic energy which has interacted with an object, the image thus showing heterogeneities in the object.

Abstract: An ultrasonic inspection system for inspecting a test object and producing substantially artifact-free images, which system includes (1) a sound source for emitting ultrasonic energy toward a test object, (2) a liquid crystal detector for detecting emitted ultrasonic energy and displaying an image, and (3) a coupling medium for sonically coupling the sound source, the test object and the detector. The ultrasonic energy is emitted at each of a plurality of frequencies within a predetermined range. It has been determined that the ultrasonic energy insonifing the object can be caused to scan the object and be angularly varied with respect thereto. Moreover, the rate of frequency scanning is substantially less that the detector image decay so as to produce a substantially flicker-free image. The angular variation is performed by rocking the sound source through a small angle, such as 2.degree. to 6.degree. relative to the liquid crystal detector.

Abstract: An acoustic imaging system which employs a liquid crystal cell for detecting acoustic energy and displaying an image. The cell includes a layer of liquid crystal material which is disposed between and encapsulated by a pair of cover members. At least one of the cover members is a laminated structure having at least two plies. The plies are of different materials and the thickness of each ply is governed by the expression n .lambda./2, where n is an integer, and .lambda. is the wavelength of the acoustic energy in the cover materials. This structure enhances cell rigidity and the uniform of thickness of the liquid crystal layer in larger sized cells, while maintaining good transmission for energy angularly incident on the cell.

Abstract: There is disclosed herein an apparatus and method for producing a substantially uniform acoustic field for use with a liquid crystal cell to produce a substantially artifact-free image of an object. The apparatus and method include moving an ultrasonic transducer toward and away from an object, a distance effective to cause adjacent constructive and destructive zone patterns to in effect overlie each other. The period of reciprocation is less than the time for onset of image decay, but greater than the image rise time so as to assure image formation. In addition, the frequency and/or phase of the acoustic energy can be varied so as to further enhance the image.Electro-mechanical and piston driven embodiments are disclosed for reciprocating the transducer.

Abstract: There is disclosed herein an orthoscopic ultrasonic imaging system which includes an acoustic transducer for insonifying an object to be inspected and an improved liquid crystal detector cell for receiving an imaging beam from the insonified object and for displaying a visible image.An acoustic biasing field is applied to the liquid crystal cell for raising the cell to an acousto-optic threshold which permits detection and display of low intensity imaging signals. Using the improved liquid crystal system, low intensity, acoustic fields [e.g. less than 10.sup.-3 w/cm.sup.2 (watts per square centimeter)] can be detected and displayed, and the object being examined can be insonified with low intensity ultrasonic beams.

Abstract: There is disclosed herein an ultrasonic imaging system using a liquid crystal detector cell and a source of non-coherent acoustic energy to produce substantially artifact-free images. The ultrasound source and cell are matched with one another, and the source is caused to operate over a range of frequencies or phases so as to produce the non-coherent ultrasonic energy. The frequency response of the cell and its response time are matched to the operating characteristics of the transducer. The transducer may be mounted in a pendulum-like sector scanning apparatus so as to assure a uniform insonification of the object, a uniform beam and a substantially uniform non-coherent insonification of the cell. The movement of the scanning apparatus is also matched to the cell and the transducer characteristics.

Abstract: There is disclosed herein a movable, ultrasonic transducer array for use in an ultrasonic inspection system that employs a signal detector and display of the liquid crystal cell type. The movable array uniformly insonifies the object to be inspected and is particularly suitable for inspecting large objects or large areas of an object. The array may include a plurality of sending or emitting transducers which are held in substantially parallel alignment so that their transmission or radiation axes are parallel. The array is part of an assembly which includes a support for holding the transducers and a drive system for moving the array and support along a predetermined path.In a first specific embodiment, the array is mounted on a support which moves along a circular path while maintaining the relative horizontal and vertical positions of the transducers. That movement is accomplished by use of a drive and linkage system which provides for an eccentric-like movement.

Abstract: There is disclosed herein an ultrasonic imaging system for use in non-destructively testing objects, which system includes a source of ultrasonic energy, a liquid crystal detector cell and an optical viewing system. The liquid crystal detector cell includes a pair of acoustically transmissive covers which encase a nematic liquid crystal material. The material exhibits an acousto-optic effect, and in particular, exhibits birefringence in response to ultrasonic energy. The cell construction, geometry, and material are acoustically matched to the frequencies of the insonifying ultrasonic transducer so as to optimize the performance of the cell. The covers are substantially acoustically transparent to ultrasonic energy incident on the cover at both normal and oblique attitudes. The acoustic impedance of the covers match as closely as possible to that of the coupling medium.

Abstract: There is disclosed herein an acoustic or ultrasonic power meter which includes a liquid crystal cell for detecting acoustic energy and a control circuit for applying an electric field to said cell. The liquid crystal cell includes a liquid crystal material having elongated molecules. The preferred liquid crystal is in the form of a layer of the nematic type which is homeotropically aligned. The elongated liquid crystal molecules exhibit positive dielectric anisotropy wherein the dielectric constant parallel to the molecule's axis is greater than the dielectric constant perpendicular to the molecule's axis. In the unexcited condition, the nematic layer is dark. In the ultrasonically excited condition, the nematic layer exhibits birefringence. A restoring electric force can be applied to the liquid crystal material to suppress the acoustically-induced birefringence condition of the cell to the dark appearance associated with the unexcited condition.

Abstract: There is disclosed herein a method for producing a liquid crystal display or cell which has a liquid crystal film positioned between a pair of substrate members whose surfaces have been ultrasonically surface treated so as to cause the liquid crystal molecules to be aligned in a predetermined manner.The method includes ultrasonically treating the surface of the substrate which contacts the liquid crystal film so as to form microgrooves or striations. The surface is treated by immersing the substrate in a liquid bath, ultrasonically forming a column of cavitation bubbles which is directed to the substrate where the cavitation bubbles collapse on the substrate, and moving the substrate through the liquid at a predetermined speed so as to form microgrooves or striate the surface of the substrate. Using two such treated substrates, a liquid crystal cell is prepared in the form of a sandwich of substrate/liquid crystal/substrate.

Abstract: There is disclosed herein a portable device for inspecting bodies for internal flaws or other internal features. The device is constructed so as to be mounted on the surface of the body, emit and receive ultrasonic energy, and display the same on a liquid crystal display. The device includes a first housing member for supporting a transducer in relation to the surface being inspected. The device also includes a second housing member for supporting and positioning the liquid crystal display in relation to the surface and in relation to the transducer. Interconnecting means are provided for adjustably interconnecting the two members and fixing their positions in a reflection-receiving relation. The liquid crystal support housing is a substantially hollow tubular member having a viewing end and a surface contacting end. The liquid crystal display is positioned intermediate the ends.

Abstract: There is disclosed herein an ultrasonic system for detecting internal discontinuities in a body. The system includes: an ultrasonic transducer for directing sonic energy toward a body; a liquid crystal, acousto-optical detector cell for detecting ultrasonic energy passing through said body; an optical system for illuminating said liquid crystal cell; and a liquid medium for coupling the transducer body and cell.The acousto-optical cell includes a pair of substantially rigid covers, a liquid crystal material positioned between said covers and a peripheral spacer and sealing member surrounding said liquid crystal and sealingly engaging said covers. Each of the covers is substantially acoustically transparent and at least one of said covers is optically transparent. The optically transparent cover is a laminate having at least three layers, with each of said layers of said laminate having a thickness much much less than 1/4 of the wave length of the ultrasonic energy propagating through said layer.