Ultrasonic probe and ultrasonic diagnostic apparatus
The present invention relates to an ultrasonic probe including a piezoelectric element, a first acoustic matching layer provided on the front face of the piezoelectric element and formed of a solid inorganic material, and a second acoustic matching layer provided on the first acoustic matching layer and formed of a mixture of an organic resin and 10 to 30% by volume of oxide powder with a density of 6.5 g/cm 3 or more.
1. An ultrasonic probe, comprising:
a piezoelectric element;
a first acoustic matching layer provided on the front face of the piezoelectric element and formed of a solid inorganic material; and
a second acoustic matching layer provided on the first acoustic matching layer and formed of a mixture of an organic resin and 10 to 30% by volume of oxide powder with a density of 6.5 g/cm 3 or more.
2. The ultrasonic probe according to claim 1 , wherein the oxide powder is of a perovskite structure comprising 50% or more of PbO and 1% or more of Nb 2 O 5 .
3. The ultrasonic probe according to claim 1 , wherein the oxide powder is selected from the group consisting of CeO 2 , Pr 2 O 3 , Nd 2 O 3 , Yb 2 O 3 , and Lu 2 O 3 .
4. The ultrasonic probe according to claim 1 , wherein the first acoustic matching layer is formed of a solid inorganic material selected from the group consisting of a ceramics including SiO 2 , MgO and Al 2 O 3 , a ceramics including Si 3 N 4 , AlN, Al 2 O 3 and ZrO 2 , a ceramics including calcium silicate and lithium aluminosilicate, a fluorophlogophite ceramics, and a hexagonal boron nitride ceramics.
5. The ultrasonic probe according to claim 1 , wherein the piezoelectric element includes a piezoelectric material and a pair of electrodes formed on the front face and the back face of the piezoelectric material.
6. The ultrasonic probe according to claim 5 , wherein the piezoelectric material is formed of a single crystalline material having a composition represented by:
Pb(B1 1-x , Ti x )O 3 ,
where 0.3≦x≦0.6, and B1 is at least one element selected from the group consisting of Zr, Sn and Hf.
7. The ultrasonic probe according to claim 5 , wherein the piezoelectric material is formed of a single crystalline material represented by:
Pb(B1, B2) 1-x Ti x O 3 ,
where 0.04≦x≦0.55, B1 is at least one element selected from the group consisting of Zn, Mg, Ni, Sc, In and Yb, and B2 is at least one element selected from the group consisting of Nb and Ta.
8. The ultrasonic probe according to claim 1 , further comprising an acoustic lens formed on the second acoustic matching layer.
9. The ultrasonic probe according to claim 1 , further comprising a third acoustic matching layer formed on the second acoustic matching layer.
10. The ultrasonic probe according to claim 9 , further comprising an acoustic lens formed on the third acoustic matching layer.
11. The ultrasonic probe according to claim 1 , further comprising a backing material provided on the back face of the piezoelectric element.
12. The ultrasonic probe according to claim 1 , wherein the piezoelectric element, the first acoustic matching layer, and the second acoustic matching layer are one-dimensionally or two-dimensionally arrayed.
13. An ultrasonic diagnostic apparatus, comprising:
an ultrasonic probe comprising: an acoustic backing layer; a piezoelectric element provided on the front face of the acoustic backing layer; a first acoustic matching layer provided on the front face of the piezoelectric element and formed of a solid inorganic material; a second acoustic matching layer provided on the front face of the first acoustic matching layer and formed of a mixture of an organic resin and 10 to 30% by volume of oxide powder with a density of 6.5 g/cm 3 or more; and an acoustic lens provided on the front face of the second acoustic matching layer, and
a ultrasonic-probe control unit connected to the ultrasonic probe via a cable.
14. The apparatus according to claim 13 , wherein the oxide powder is of a perovskite structure comprising 50% or more of PbO and 1% or more of Nb 2 O 5 .
15. The apparatus according to claim 13 , wherein the oxide powder selected from the group consisting of CeO 2 , Pr 2 O 3 , Nd 2 O 3 , Yb 2 O 3 , and Lu 2 O 3 .
16. The apparatus according to claim 13 , wherein the first acoustic matching layer is formed of a solid inorganic material selected from the group consisting of a ceramics including SiO 2 , MgO and Al 2 O 3 , a ceramics including Si 3 N 4 , AlN, Al 2 O 3 and ZrO 2 , a ceramics including calcium silicate and lithium aluminosilicate, a fluorophlogophite ceramics, and a hexagonal boron nitride ceramics.
17. The apparatus according to claim 13 , wherein the piezoelectric element includes a piezoelectric material and a pair of electrodes formed on the front face and the back face of the piezoelectric material.
18. The apparatus according to claim 17 , wherein the piezoelectric material is formed of a single crystalline material having a composition represented by:
Pb(B1 1-x , Ti x )O 3 ,
where 0.3≦x≦0.6, and B1 is at least one element selected from the group consisting of Zr, Sn and Hf.
19. The apparatus according to claim 17 , wherein the piezoelectric material is formed of a single crystalline material represented by:
Pb(B1, B2) 1-x Ti x O 3 ,
where 0.04≦x≦0.55, B1 is at least one element selected from the group consisting of Zn, Mg, Ni, Sc, In and Yb, and B2 is at least one element selected from the group consisting of Nb and Ta.
20. The apparatus according to claim 13 , wherein the piezoelectric element, the first acoustic matching layer, and the second acoustic matching layer are one-dimensionally or two-dimensionally arrayed.