| 摘要 |
The ultrasonic sensor (2) comprises a polymer film (4) which is mounted in its edge area and activated piezoelectrically in a subregion (8). A first electrode (16), e.g. in the form of a pin (16A), is arranged at a prescribed distance (a) in front of the activated subregion (8) and without touching the latter. A second electrode (26), e.g. in the form of a ring, is arranged spatially separated from the active region (8). The space (42, 44) between the electrodes (16, 26) and the activated subregion (8) is respectively filled with a strong electrolyte (46, 48), e.g. cooking salt solution. The electric signal tap on the activated zone (8) via the electrolytes (46, 48) produces a high sensitivity of the ultrasonic sensor (2). The latter is provided, in particular, for measuring shock waves having a high pressure amplitude, preferably for lithotripsy. <IMAGE>
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