Patent ID: 8323201

Claim:
A multi-focus acoustic lens for focusing ultrasonic pulses transmitted by a concave transducer array at desired locations in an object, the concave transducer array having a multiplicity of individual concave transducer rows for generating multiple images of the object in a range and azimuthal direction, comprising: (a) a multiplicity of lens rows forming an entire lens comprised of a center lens row and a plurality of uncentered lens rows forming at least two outer lens rows relative the said center lens row when said entire lens is viewed elevationally, wherein each said lens row has an inner surface and an outer surface, wherein each said outer surface is configured to form a convex shape in the azimuthal direction, wherein each said inner surface is configured to form a concave arcuate surface in the azimuthal direction, wherein, each said lens row is elevationally and azimuthally aligned to cover an entire transmit/receive area of a respective individual concave transducer row to focus a beam transmitted through the said entire lens in an elevational and azimuthal direction, wherein, when a pair of said uncentered lens rows are symmetric in an elevation direction with respect to an azimuthal centerline of the said center lens rows, said uncentered lens row pair has a same focal range, wherein the said inner surface of each of said lens rows varies in height in a range direction relative to a lens row of the entire lens to which it is adjacent, wherein said each lens row has a constant curvature and a radius when viewed cross-sectionally, wherein the said center lens row has a smaller radius and a larger curvature in size as compared to each of the said radius and each of the said curvature of each said uncentered lens row, so that a center portion of the said center lens row is not coincident with a center portion of an arc formed by any symmetric uncentered lens row pair, wherein the said lens rows have f-numbers which are essentially constant with one another, wherein each said lens row is sized to simultaneously deliver all components of an echo received by the entire lens to a beamformer; and (b) a moving mechanism operably coupled to the entire lens for moving the entire lens to one or more radial positions with respect to the object being imaged thereby generating the multiple images in the range and azimuthal direction.