Ultrasonic probe
View Patent ↗An ultrasonic probe includes piezoelectric elements each including grooves parallel to each other and arrayed in a direction substantially parallel to the grooves, and a mixed member which is to fill the grooves and obtained by mixing in a nonconductive resin member a nonconductive granular substance with a coefficient of thermal expansion of not more than substantially 10 −5 K −1 .
1. An ultrasonic probe, comprising:
piezoelectric elements each including grooves parallel to each other and arrayed in a direction of the grooves; and
a mixed member which fills the grooves and is obtained by mixing, in a nonconductive resin member, a nonconductive granular substance with a coefficient of thermal expansion of not more than substantially 10 −5 K −1 , wherein a lower limit of a weight ratio of the nonconductive granular substance to the mixed member is 30 wt %, and an upper limit thereof is determined by a largest amount of the nonconductive granular substance that can be mixed in the nonconductive resin member.
2. A probe according to claim 1 , wherein a mixing ratio of the resin member and the granular substance is determined on the basis of a temperature of the piezoelectric elements and at least one of a stress value that the piezoelectric element is configured to endure, a specific gravity of the mixed member, and a coefficient of thermal expansion of the mixed member.
3. A probe according to claim 1 , wherein the specific gravity of the mixed member is no more than approximately one-third a specific gravity of the piezoelectric elements.
4. A probe according to claim 1 , wherein the coefficient of thermal expansion of the mixed member is determined on the basis of a temperature of the mixed member in use.
5. A probe according to claim 1 , wherein the mixed member has such a coefficient of thermal expansion that the mixed member generates a stress that does not break the piezoelectric elements even when the mixed member thermally expands.
6. A probe according to claim 1 , wherein a grain size of the granular substance is no more than substantially one-eighth a wavelength of an ultrasonic wave that the piezoelectric elements transmit and receive.
7. A probe according to claim 1 , wherein the grooves are formed in each of the piezoelectric elements such that an intensity of an ultrasonic wave to be transmitted/received gradually decreases from a central portion toward an end of a direction in which the grooves are arrayed.
8. A piezoelectric transducers comprising:
a piezoelectric element including grooves; and
a mixed member which fills the grooves and is obtained by mixing, in a nonconductive resin member, a nonconductive granular substance with a coefficient of thermal expansion of not more than substantially 10 −5 K −1 , wherein a lower limit of a weight ratio of the nonconductive granular substance to the mixed member is 30 wt %, and an upper limit thereof is determined by a largest amount of the nonconductive granular substance that can be mixed in the nonconductive resin member.
9. An ultrasonic probe, comprising:
piezoelectric elements each including grooves parallel to each other and arrayed in a direction of the grooves; and
a mixed member which fills the grooves and is obtained by mixing, in a nonconductive resin member, a nonconductive granular substance with a coefficient of thermal expansion of not more than substantially 10 −5 K −1 , wherein a grain size of the granular substance is no more than substantially one-eighth a wavelength of an ultrasonic wave that the piezoelectric elements transmit and receive.