Claims
- 1. An ultrasonic imaging device comprising at least one acoustic transducer each transducer being associated with its own acoustic focusing system, a means to move the point of focus of each focusing system progressively to different coordinates within an acoustically transmissive volume to gather data as to the acoustic reflectivity of matter within said volume at said different coordinates, and means to construct an image or images of the volume from said data, each focusing system being a confocal acoustic focusing system including a first acoustic lens associated with the transducer, an aperture plate having a pinhole upon which the first lens is focused, and a second acoustic lens on an opposite side of the aperture plate to the first lens and focused upon said pinhole and said point of focus respectively,wherein an acoustically transparent and optically reflective diaphragm is applied spanning each pinhole, and each diaphragm is associated with an optical monitoring means generating a beam incident upon and receiving the beam as reflected by the diaphragm, to interrogate movement of the diaphragm responsive to passage of acoustic energy therethrough, whereby to detect acoustic energy reflected to the pinhole from the point of focus.
- 2. A device according to claim 1, comprising multiple acoustic transducers and their associated confocal focusing systems, disposed in an array.
- 3. A device according to claim 2, wherein the array is a two-dimensional planar array.
- 4. A device according to claim 3, wherein the means to move the points of focus includes actuators to move the array on two perpendicular axes parallel to the plane of the array and a third axis perpendicular to the plane of the array.
- 5. A device according to claim 4, wherein the actuators moving the array in its plane do so in a dither pattern of dimensions in accordance with the spacing of the axes of the focusing system in the array.
- 6. A device according to claim 1, wherein each transducer is an electroacoustic transducer connected to a driver for applying pulses of electrical energy at an ultrasonic frequency to the transducer to cause it to transmit pulses of acoustic energy.
- 7. A device according to claim 1, including a membrane providing a coupling layer between said at least one focusing system and said volume to be imaged.
- 8. A device according to claim 1, wherein each monitoring means is an optical laser interferometer.
- 9. A device according to claim 8, including an array of confocal acoustic focusing systems and their associated interferometers.
- 10. A device according to claim 9, including an array of confocal acoustic focusing systems, and wherein the associated interferometers share a single laser having a beam splitter in an interrogation beam path providing an array of parallel beams, one to interrogate each of the diaphragms associated with each of the array of confocal acoustic focusing systems, a beam splitter in a reference beam path to provide an array of parallel beams for recombination, one with each of the reflected parallel beams of the interrogation path, and an array of optical detectors one to receive each of the recombined beams.
- 11. A device according to claim 9, including an array of optical detectors, one array for receiving optical signals from each of the diaphragms interrogated and means for scanning the optical signals over each array to direct successive samples of the received optical signals to successive detectors of the array.
- 12. A device according to claim 11, wherein each array of optical detectors is a charge coupled array storing the samples for later recovery.
- 13. A pulse-echo acoustic system including an acoustic transducer utilized to insonify a target with pulses of acoustic energy transmitted along a path from the transducer to the target, and means to monitor acoustic energy reflected back from the target along the same path, wherein the monitoring means comprises an optical interferometer in which an acoustically transparent but optically reflective diaphragm, which is located on the path between the transducer and the target, forms a reflective element in an optical interrogation beam path of the optical interferometer.
- 14. A pulse-echo acoustic system according to claim 13, wherein the path from the transducer to the target incorporates an acoustic focusing system.
- 15. A pulse-echo acoustic system according to claim 14, wherein the acoustic focusing system is a confocal acoustic focusing system.
- 16. A pulse-echo acoustic system according to claim 13, wherein the diaphragm spans a pinhole of the confocal acoustic focusing system.
REFERENCE TO RELATED APPLICATION
This Application is a Continuation of Internation Patent Application PCT/CA96/00432 Filed Jun. 26, 1996.
US Referenced Citations (7)
Continuations (1)
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Number |
Date |
Country |
Parent |
PCT/CA96/00432 |
Jun 1996 |
US |
Child |
09/219323 |
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US |