| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To improve the sensitivity by making the operation possible at the optimum frequency even in the ultrasonograph in which the piezoelectric elements are fixed on the substrate for easier production. <P>SOLUTION: The piezoelectric element 41 transmits the ultrasonic waves into the object to be measured according to the drive signal inputted with a drive circuit 32. The piezoelectric elements 41 and 42 are held on the substrate 43, An acoustic matching layer 45 is provided on the top surfaces of the piezoelectric elements 41 and 42. The drive circuit 32 excites the piezoelectric elements 41 and 42 across the thickness thereof 41 and 42 at the specified frequency to drive the piezoelectric elements 41 and 42. The drive frequency is set higher than the intermediate frequency between the resonance frequency across the thickness and the anti-resonance frequency before the piezoelectric elements 41 and 42 are held on the substrate 43. <P>COPYRIGHT: (C)2005,JPO&NCIPI</p> |
