| 摘要 |
PURPOSE:To obtain a wide receiving opening extending over a wide range from a shallow part to a deep part without extending length of a delay line by providing a first and a second delay means in a receiving beam former. CONSTITUTION:The delay quantity to a receiving signal obtained by ultrasonic transducers(USTs) 1 (p), 1 (q) (1<p<n/2, n/2<q<n) positioned between USTs 1 (1), 1 (n) of both end parts and a UST 1 (n/2) of the center part is fixed by a variable focus delay line part 8. Subsequently, as the focus moves successively from the shallowest part to the deepest part, the delay quantity to a receiving signal obtained by USTs 1 (p+1),... 1 (q-1) placed between the USTs 1 (p), 1 (q) is decreased successively. Also, the delay quantity to a receiving signal obtained by USTs1 (1),...1 (p-1); 1 (q+1),... 1 (n) is decreased. In such a state, by a deflected/fixed focus delay line part 7, the fixed focus is aligned with the deepest part, and also, a delay having a step difference on the center side and both the end sides is executed. |
