Transducer including coupler fitted in slits between beams
A transducer includes a base, beams, and a coupler. The beams each include a piezoelectric layer, a first electrode layer, and a second electrode layer. The coupler is fitted in slits between adjacent beams to define a connection between the beams. The coupler extends from an upper portion of the base into each of the slits without a break. A Young's modulus of the material of the coupler is lower than a Young's modulus of the material of the piezoelectric layer. A maximum thickness of the coupler in the upper portion of the base in the direction of the central axis of the base is greater than a thickness of each of the beams.
1. A transducer, comprising:
a base that is ring-shaped;
beams each including a fixed end portion connected to an inner periphery of the base and a tip portion located opposite the fixed end portion, each of the beams extending such that the tip portion is farther than the fixed end portion from the inner periphery; and
a coupler fitted in slits between adjacent ones of the beams to define a connection between the beams and extending from an upper portion of the base into each of the slits without a break; wherein
the beams each include:
a piezoelectric layer; and
a first electrode layer and a second electrode layer on opposite sides of the piezoelectric layer in a direction of a central axis of the base such that the second electrode layer faces at least a portion of the first electrode layer with the piezoelectric layer interposed therebetween in the direction of the central axis;
a Young's modulus of a material of the coupler is lower than a Young's modulus of a material of the piezoelectric layer; and
a maximum thickness of the coupler in the upper portion of the base in the direction of the central axis of the base is greater than a thickness of each of the beams.
2. The transducer according to claim 1 , wherein
the upper portion of the base includes recesses connected to a respective one of the slits; and
the coupler is fitted inside each of the recesses and the corresponding one of the slits without a break.
3. The transducer according to claim 2 , wherein a maximum thickness of the coupler on a bottom surface of each of the recesses defined by side walls is greater than a height of each of the side walls, where the maximum thickness of the coupler on the bottom surface of each of the recesses defined by side walls is a dimension in the direction of the central axis of the base.
4. The transducer according to claim 2 , wherein a maximum width of each of the recesses viewed in the direction of the central axis of the base is greater than a width of a corresponding one of the slits, where the maximum width of each of the recesses is a dimension orthogonal or substantially orthogonal to a direction in which the corresponding one of the slits extends.
5. The transducer according to claim 1 , wherein the Young's modulus of the material of the coupler is less than or equal to about 1 GPa.
6. The transducer according to claim 1 , wherein
the piezoelectric layer is made of an inorganic material; and
the coupler is made of an organic material.
7. The transducer according to claim 6 , wherein the coupler is made of silicone resin or fluoroelastomer.
8. The transducer according to claim 6 , wherein the piezoelectric layer is made of lithium niobate or lithium tantalate.
9. The transducer according to claim 1 , wherein the slits each include a portion in which the coupler is not located.
10. The transducer according to claim 9 , wherein the tip portions of the beams are not connected to each other by the coupler and are spaced away from each other.
11. The transducer according to claim 1 , wherein
at least one of the beams includes a through-hole extending through the at least one of the beams in the direction of the central axis of the base; and
the through-hole is spaced away from the slits.
12. The transducer according to claim 11 , wherein
the tip portions of the beams point to the central axis of the base when viewed in the direction of the central axis;
the beams each include a through-hole extending in the direction of the central axis; and
the through-holes of the beams are symmetrical about the central axis when viewed in the direction of the central axis.
13. A transducer, comprising:
a base that is ring-shaped;
beams each including a fixed end portion connected to an inner periphery of the base and a tip portion located opposite the fixed end portion, each of the beams extending such that the tip portion is farther than the fixed end portion from the inner periphery; and
a coupler fitted in slits between adjacent ones of the beams to define a connection between the beams and extending from an upper portion of the base into each of the slits without a break; wherein
the beams each include:
a piezoelectric layer; and
a first electrode layer and a second electrode layer on opposite sides of the piezoelectric layer such that the second electrode layer faces at least a portion of the first electrode layer with the piezoelectric layer interposed therebetween;
a Young's modulus of a material of the coupler is lower than a Young's modulus of a material of the piezoelectric layer;
the upper portion of the base includes recesses connected to the respective slits; and
the coupler is fitted inside each of the recesses and the corresponding one of the slits without a break.
14. The transducer according to claim 13 , wherein a maximum thickness of the coupler on a bottom surface of each of the recesses defined by side walls is greater than a height of each of the side walls, where the maximum thickness of the coupler is a dimension in a direction of a central axis of the base.
15. The transducer according to claim 13 , wherein a maximum width of each of the recesses viewed in the direction of the central axis of the base is greater than a width of a corresponding one of the slits, where the maximum width of each of the recesses is a dimension orthogonal or substantially orthogonal to a direction in which the corresponding one of the slits extends.
16. The transducer according to claim 13 , wherein the Young's modulus of the material of the coupler is less than or equal to about 1 GPa.
17. The transducer according to claim 13 , wherein
the piezoelectric layer is made of an inorganic material; and
the coupler is made of an organic material.
18. The transducer according to claim 17 , wherein the coupler is made of silicone resin or fluoroelastomer.
19. The transducer according to claim 17 , wherein the piezoelectric layer is made of lithium niobate or lithium tantalate.
20. The transducer according to claim 13 , wherein the slits each include a portion in which the coupler is not located.