| 摘要 |
PROBLEM TO BE SOLVED: To provide an excellent ultrasonic diagnosis apparatus with a light and handy probe which can be opened and controlled in the minor axial direction (direction of a lens). SOLUTION: An acoustic matching layer 3 is thin at the center of opening with the thickness being Tc, equivalent to a quarter wavelength, at least 1.3 times of Tc along the rim of the opening. Therefore, the sensitivity of a high frequency component is high at the center of opening and that of a low frequency component is low along the rim of the opening. So by increasing the acoustic impedance of back side loads B1-B5 along the rim of the opening, the sensitivity of the low frequency component is at the same level both at the center and along the rim of the opening. In addition, as the sensitivity for received signals of the high frequency component is high in the short distance, a thin beam with a narrow opening can be obtained in the short distance and a highly directive beam with a wide opening can be obtained in the long distance by using a dynamic filter 7 with a high sensitivity for received signals of the low frequency component in the long distance. Therefore, a strong convergence by an acoustic lens 4 can be possible. |
