Rokuro Uchida at Aloka® had similar research on the linear-array technology in the late 1960s predating their European counterpart. In 1971 they published in Japanese (and presented at the Japan Society of Ultrasonics in Medicine) a system based on 200 closely interspaced transducers. Electronic switching and use of overlapping groups of 20 small elements yielded 2-D images with a field depth of 20 cm at a rate of 17/frames per second. The company produced this first prototype linear array scanner in the same year. It was a relatively large machine resembling the mechanical scanner 'Vidoson' from Siemens in Germany.
Rectangular real-time image of a sponge type phantom. Image quality was nevertheless un-impressive.
Images courtesy of Aloka.
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