| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an ultrasonic vibrator in which ultrasonic waves from a high frequency component to a low frequency component are transmitted-received from its middle portion to its peripheral portion and a method of manufacturing the same. <P>SOLUTION: Press moldings 11a, 11b, 11c, 11d of different compositions are combined and quickly heated to be integrally sintered by a discharge plasma sintering apparatus such that a sintered compact 12 is produced to change sound velocity distribution characteristics successively from a high frequency to a low frequency from its middle portion to its peripheral portion. Then, the sintered compact 12 is cut into prescribed thickness and afterwards, an ultrasonic wave radiation plane and the back facing the ultrasonic wave radiation plane are mutually parallel-polished such that the vibrator capable of transmitting-receiving the ultrasonic waves from the high frequency component to the low frequency component from its middle portion to its peripheral portion is easily produced at low cost. Particularly, when the ultrasonic vibrator is used as an ultrasonic probe, the high frequency component of the ultrasonic wave is transmitted-received in a narrow opening area of the middle portion within one probe and the low frequency component of the ultrasonic wave is transmitted-received in a wide opening area. Thus, tissue of a nearby part is observed with an excellent resolution from the ultrasonic waves of the high frequency component, and an ultrasonic image of sufficient depth is obtained from the ultrasonic waves of the low frequency component without deteriorating a resolution in a distant part (azimuth). <P>COPYRIGHT: (C)2004,JPO</p> |
