| 摘要 |
PROBLEM TO BE SOLVED: To provide a piezoelectric element for a ultrasonic sensor which is small-sized and low in the cost by shortening reverberation at the time of transmission and, furthermore, improving sensor performance by raising a reception voltage. SOLUTION: In a ultrasonic sensor, a piezoelectric element 1 to be used as a transmission/reception means for performing transmission and reception of a ultrasonic wave is constituted with a disk like piezoelectric body 11 and electrodes 2 and 3 formed on its both end surfaces 12 and 13. The piezoelectric body 11 forms the edge surface 12 which becomes a radiation surface in a recessed surface, is formed as the one which has a distribution in a diameter and the thickness by expanding all periphery of a side face 14 outward and can shorten a reverberation time by reducing a mechanical quality coefficient Q value. Also, since the radiation surface 12 is a recessed surface, effects of converging the radiated ultrasonic wave and of raising a reception voltage can also be obtained.
|
