| 摘要 |
PURPOSE:To reduce a side rove of the transmitting/receiving beams in the slicing direction by arranging plural ultrasonic oscillators in an array form and forming a weighing means to the sensitivity distribution in the direction square to the lineup direction in each oscillator. CONSTITUTION:Of electrodes installed on both sides of a basic material 25 which consists of a ceramics or the like, the electrode at the signal side is divided in the slicing direction, and a voltage for polarization different in the scope Va - Vb is applied to electrodes 22 and 27. For example, to the outer side electrodes from the central electrode, voltages V1, V2, V3...Vn (V1>V2>V3>...>Vn) are applied in order, the oscillators nearer the center are polarized by higher voltages, and a piezoelectric body 28 with a high electric sound conversion efficiency is obtained. After the polarization, the divided type electrodes 27 are removed and electrodes 21 are installed. By using the piezoelectric body 28 made in such a way for an array type ultrasonic probe, a weighing means of the transmitting/receiving sensitivity in the slicing direction is to be made. As a result, a good ultrasonic directivity of little side rove, not only in the scanning direction, but also in the slicing direction, can be obtained, and a high picture quality of tomogram image can be realized. |
