Piezoelectric/electrostrictive film device

1. A piezoelectric/electrostrictive film device comprising a ceramic substrate, and a piezoelectric/electrostrictive actuator including a laminate formed by sequentially layering at least one lower electrode, at least one piezoelectric/electrostrictive layer, and at least one upper electrode on said substrate, said at least one piezoelectric/electrostrictive layer covering an upper surface of said at least one lower electrode and a lower surface of said at least one upper electrode and including a protruded portion protruding beyond edges thereof;

wherein said protruded portion of said piezoelectric/electrostrictive layer is coupled to said substrate via a coupling member, such that said coupling member completely couples at least an entire lower portion of said protruded portion of said piezoelectric/electrostrictive layer to said substrate; and

wherein a flexural displacement of said device is substantially the same as, and a resonant frequency of said device is at least 3% larger than, that of a piezoelectric/electrostrictive film device comprising the same materials and the same configuration as said device but not including said coupling member.

2. The piezoelectric/electrostrictive film device according to claim 1 , wherein a penetration depth of a Microvickers hardness indenter into said coupling member is larger than that of the piezoelectric/electrostrictive layer and lower than 1.3 μm when measured by using a micro hardness tester and a Diamond Vickers indenter having a diagonal angle of 136 degrees at a load of 1 gf and a penetration speed of 0.145 gf/sec.

3. The piezoelectric/electrostrictive film device according to claim 1 , wherein said coupling member of said piezoelectric/electrostrictive film device has a Young's modulus exceeding 2.4 GPa, but lower than that of said piezoelectric/electrostrictive layer.

4. A piezoelectric/electrostrictive film device comprising a ceramic substrate, and a piezoelectric/electrostrictive actuator including a laminate formed by sequentially layering at least one lower electrode, at least one piezoelectric/electrostrictive layer, and at least one upper electrode on said substrate, said at least one piezoelectric/electrostrictive layer covering an upper surface of said at least one lower electrode and a lower surface of said at least one upper electrode and including a protruded portion protruding beyond edges thereof;

wherein said protruded portion of said piezoelectric/electrostrictive layer is coupled to said substrate via a coupling member;

wherein a flexural displacement of said device is substantially the same as, and a resonant frequency of said device is at least 3% larger than, that of a piezoelectric/electrostrictive film device comprising the same materials and the same configuration as said device but not including said coupling member; and

wherein said coupling member comprises an organic-inorganic hybridized material.

5. A piezoelectric/electrostrictive film device comprising a ceramic substrate, and a piezoelectric/electrostrictive actuator including a laminate formed by sequentially layering at least one lower electrode, at least one piezoelectric/electrostrictive layer, and at least one upper electrode on said substrate, said at least one piezoelectric/electrostrictive layer covering an upper surface of said at least one lower electrode and a lower surface of said at least one upper electrode and including a protruded portion protruding beyond edges thereof;

wherein said protruded portion of said piezoelectric/electrostrictive layer is coupled to said substrate via a coupling member;

wherein a flexural displacement of said device is substantially the same as, and a resonant frequency of said device is at least 3% larger than, that of a piezoelectric/electrostrictive film device comprising the same materials and the same configuration as said device but not including said coupling member;

wherein a penetration depth of a Microvickers hardness indenter into said coupling member is larger than that of the piezoelectric/electrostrictive layer and lower than 1.3 μm when measured by using a micro hardness tester and a Diamond Vickers indenter having a diagonal angle of 136 degrees at a load of 1 gf and a penetration speed of 0.145 gf/sec; and

wherein said coupling member comprises an organic-inorganic hybridized material.

6. The piezoelectric/electrostrictive film device according to claim 4 , wherein an entirety of said protruded portion of said piezoelectric/electrostrictive layer is covered by said coupling member.

7. The piezoelectric/electrostrictive film device according to claim 1 , wherein said coupling member contains a coloring agent.

8. The piezoelectric/electrostrictive film device according to claim 7 , wherein said coloring agent is a fluorescent pigment.

9. The piezoelectric/electrostrictive film device according to claim 8 , wherein said fluorescent pigment is an organic substance being removable by subjecting it to thermal processing at a temperature at which said organic substance is decomposed or higher.

10. The piezoelectric/electrostrictive film device according to claim 1 , wherein said piezoelectric/electrostrictive actuator includes a laminate layer formed by alternately layering a predetermined number of lower electrodes, a predetermined number of piezoelectric/electrostrictive layers, and a predetermined number of upper electrodes in order on said substrate.

11. A piezoelectric/electrostrictive film device according to claim 2 , wherein said piezoelectric/electrostrictive actuator includes a laminate layer formed by alternately layering a predetermined number of lower electrodes, a predetermined number of piezoelectric/electrostrictive layers, and a predetermined number of upper electrodes in order on said substrate.

12. A piezoelectric/electrostrictive film device comprising a ceramic substrate, and a piezoelectric/electrostrictive actuator including a laminate formed by sequentially layering at least one lower electrode, at least one piezoelectric/electrostrictive layer, and at least one upper electrode on said substrate, said at least one piezoelectric/electrostrictive layer covering an upper surface of said at least one lower electrode and a lower surface of said at least one upper electrode and including a protruded portion protruding beyond edges thereof;

wherein said protruded portion of said piezoelectric/electrostrictive layer is coupled to said substrate via at least one coupling member;

wherein a flexural displacement of said device is substantially the same as, and a resonant frequency of said device is at least 3% larger than, that of a piezoelectric/electrostrictive film device comprising the same materials and the same configuration as said device but not including said coupling member; and

wherein a plurality of piezoelectric/electrostrictive actuators are provided on the substrate, and at least two adjacent piezoelectric/electrostrictive actuators are coupled with said at least one coupling member.

13. A piezoelectric/electrostrictive film device comprising a ceramic substrate, and a piezoelectric/electrostrictive actuator including a laminate formed by sequentially layering at least one lower electrode, at least one piezoelectric/electrostrictive layer, and at least one upper electrode on said substrate, said at least one piezoelectric/electrostrictive layer covering an upper surface of said at least one lower electrode and a lower surface of said at least one upper electrode and including a protruded portion protruding beyond edges thereof;

wherein said protruded portion of said piezoelectric/electrostrictive layer is coupled to said substrate via at least one coupling member;

wherein a flexural displacement of said device is substantially the same as, and a resonant frequency of said device is at least 3% larger than, that of a piezoelectric/electrostrictive film device comprising the same materials and the same configuration as said device but not including said coupling member;

wherein a penetration depth of a Microvickers hardness indenter into said coupling member is larger than that of the piezoelectric/electrostrictive layer and lower than 1.3 μm when measured by using a micro hardness tester and a Diamond Vickers indenter having a diagonal angle of 136 degrees at a load of 1 gf and a penetration speed of 0.145 gf/sec; and

wherein a plurality of piezoelectric/electrostrictive actuators are provided on said substrate, and at least two adjacent piezoelectric/electrostrictive actuators are coupled with said at least one coupling member.

14. A piezoelectric/electrostrictive film device comprising a ceramic substrate, and a piezoelectric/electrostrictive actuator including a laminate formed by sequentially layering at least one lower electrode, at least one piezoelectric/electrostrictive layer, and at least one upper electrode on said substrate, said at least one piezoelectric/electrostrictive layer covering an upper surface of said at least one lower electrode and a lower surface of said at least one upper electrode and including a protruded portion protruding beyond edges thereof;

wherein said protruded portion of said piezoelectric/electrostrictive layer is coupled to said substrate via at least one coupling member;

wherein a flexural displacement of said device is substantially the same as, and a resonant frequency of said device is at least 3% larger than, that of a piezoelectric/electrostrictive film device comprising the same materials and the same configuration as said device but not including said coupling member;

wherein a plurality of piezoelectric/electrostrictive actuators are provided at a predetermined interval on said substrate; and

wherein said at least one coupling member includes a portion formed on an upper surface of said substrate between said at least two adjacent piezoelectric/electrostrictive actuators.

15. A piezoelectric/electrostrictive film device comprising a ceramic substrate, and a piezoelectric/electrostrictive actuator including a laminate formed by sequentially layering at least one lower electrode, at least one piezoelectric/electrostrictive layer, and at least one upper electrode on said substrate, said at least one piezoelectric/electrostrictive layer covering an upper surface of said at least one lower electrode and a lower surface of said at least one upper electrode and including a protruded portion protruding beyond edges thereof;

wherein said protruded portion of said piezoelectric/electrostrictive layer is coupled to said substrate via at least one coupling member;

wherein a flexural displacement of said device is substantially the same as, and a resonant frequency of said device is at least 3% larger than, that of a piezoelectric/electrostrictive film device comprising the same materials and the same configuration as said device but not including said coupling member;

wherein a penetration depth of a Microvickers hardness indenter into said coupling member is larger than that of the piezoelectric/electrostrictive layer and lower than 1.3 μm when measured by using a micro hardness tester and a Diamond Vickers indenter having a diagonal angle of 136 degrees at a load of 1 gf and a penetration speed of 0.145 gf/sec;

wherein a plurality of piezoelectric/electrostrictive actuators are provided at a predetermined interval on said substrate; and

wherein said at least one coupling member includes a portion formed on an upper surface of said substrate between said at least two adjacent piezoelectric/electrostrictive actuators.

16. The piezoelectric/electrostrictive film device according to claim 5 , wherein an entirety of said protruded portion of said piezoelectric/electrostrictive layer is covered by said coupling member.

17. The piezoelectric/electrostrictive film device according to claim 4 , wherein a penetration depth of a Microvickers hardness indenter into said coupling member is larger than that of said piezoelectric/electrostrictive layer and lower than 1.3 μm when measured by using a micro hardness tester and a Diamond Vickers indenter having a diagonal angle of 136 degrees at a load of 1 gf and a penetration speed of 0.145 gf/sec.

18. The piezoelectric/electrostrictive film device according to claim 4 , wherein said coupling member of said piezoelectric/electrostrictive film device has a Young's modulus exceeding 2.4 GPa, but lower than that of said piezoelectric/electrostrictive layer.

19. The piezoelectric/electrostrictive film device according to claim 4 , wherein said coupling member contains a coloring agent.

20. The piezoelectric/electrostrictive film device according to claim 19 , wherein said coloring agent is a fluorescent pigment.

21. The piezoelectric/electrostrictive film device according to claim 20 , wherein said fluorescent pigment is an organic substance being removable by subjecting it to thermal processing at a temperature at which said organic substance is decomposed or higher.

22. The piezoelectric/electrostrictive film device according to claim 5 , wherein said piezoelectric/electrostrictive actuator includes a laminate layer formed by alternately layering a predetermined number of lower electrodes, a predetermined number of piezoelectric/electrostrictive layers, and a predetermined number of upper electrodes in order on said substrate.