Device for electronic focusing of ultrasonic waves

Claim 1

A devie for electronic focusing of ultrasonic waves in which an ultrasonic wave propagates in one direction and/or in another between an array of piezoelectric cells and a focal point located within a medium, in which the electric signal corresponding to said wave is transmitted with difference time-delays in the case of each cell, said time-delays being dependent in the case of each cell on the reltive positons of the focal point and the cell considered, and in which the means for producing time-delays comprise delay circuits connected to said cells, wherein said means for producing time-delays comprise a hierarchized assembly of elementary circuits arranged in plural levels, wherein the piezoelectric cells of said array are coupled only to respective elementary circuits of a first level of the hierarchized assembly and the elementary circuits of said first level and each succeeding level are respectively coupled to the elementary circuits of the respective next succeeding level of the hierarchized assembly, each elementary circuit comprising a delay line connected in parallel with a direct line to a centralizing unit, wherein the time-delay of the delay line in a elementary circuit is a function of the relative time-delay which must exist between two cells or between two elementary circuits of the hierachized assembly of elementary circuits aforesaid, and wherein each individual elementary circuit comprises a switching device for reversing the relative time-delay between the two cells or between the two elementary circuits which are connected to said individual elementary circuit.