Fig 2Convex probe · openedHover to open the probeconvex probe · 128 elements · R 50 mm · 64° · 2–5 MHz
Piezo array: the part that makes and hears the soundAcoustic stack: lens, matching layers, backingSignal path: flex, board, cable, connectorA convex probe of the 2–5 MHz abdominal class: 128 PZT elements on a 50 mm radius, 64° of arc, pitch about 0.44 mm. From the patient inward: silicone lens, two quarter-wave matching layers, the piezo array cut into elements by kerfs, and the tungsten-epoxy backing that stops each element ringing. Every element has its own trace on the flex and its own coax in the cable, so a cracked crystal, a lifted flex trace or a broken core all show the same way: one dark vertical stripe in the image. Layer thicknesses are drawn larger than life and kerfs are drawn for every second element.