EP0455342A1
Expired / Lapsed
EP
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Piezoelectric/electrostrictive actuator having at least one piezoelectric/electrostrictive film
Assignee: NGK Insulators Ltd
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Filing: 1991-03-27
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Granted: —
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Expires: 2011-03-27
Abstract
Abstract A piezoelectric/electrostrictive actuator having at least one piezoelectric/electrostrictive unit (4, 6, 8, 22, 28) each including a first electrode film (4, 22), a piezoelectric/electrostrictive film (6, 28) and a second electrode film (8, 22) which are superposed on each other on a ceramic substrate (2), or at least one piezoelectric/electrostrictive unit (16, 17) each including a plurality of patterned spaced-apart electrode film strips (16) formed on a ceramic substrate (2), and a plurality of patterned spaced-apart piezoelectric/electrostrictive film strips (17) each formed on the ceramic substrate and disposed between and in contact with adjacent ones of the electrode film strips. At least a selected portion of the ceramic substrate on which the unit or units is/are disposed has grain boundaries (26) which contain lead.
Inventors
- 👤 Yukihisa Takeuchi
- 👤 Koji Ngk Insulators Ltd. Kimura
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-28 16:53
CPC Classifications
H; H10; H10N; H10N30/00; H10N30/704; H10N30/706; H10N30/20; H10N30/204; H10N30/2041; H10N30/2042
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
147 words
A piezoelectric/electrostrictive actuator having at least one piezoelectric/electrostrictive unit (4, 6, 8, 22, 28) each including a first electrode film (4, 22), a piezoelectric/electrostrictive film (6, 28) and a second electrode film (8, 22) which are superposed on each other on a ceramic substrate (2), or at least one piezoelectric/electrostrictive unit (16, 17) each including a plurality of patterned spaced-apart electrode film strips (16) formed on a ceramic substrate (2), and a plurality of patterned spaced-apart piezoelectric/electrostrictive film strips (17) which are formed on said ceramic substrate and each of which is disposed between and in contact with adjacent ones of said electrode strips, said ceramic substrate including ceramic particles (24) and grain boundaries (26) defined by said ceramic particles, characterized in that: lead element is contained in at least a selected portion of said ceramic substrate on which said at least one piezoelectric/electrostrictive unit is disposed.
Claim 2
Dependent Claim
21 words
A piezoelectric/electrostrictive actuator according to claim 1, wherein said grain boundaries (26) contain at least 40% by weight of lead element.
Claim 3
Dependent Claim
37 words
A piezoelectric/electrostrictive actuator according to claim 1 or 2, wherein said ceramic substrate (2) includes at least one major component selected from the group consisting of aluminum oxide, magnesium oxide, zirconium oxide, aluminum nitride and silicon nitride.
Claim 4
Dependent Claim
25 words
A piezoelectric/electrostrictive actuator according to any one of claims 1-3, wherein said ceramic substrate (2) includes silicon oxide in an amount of 0.5-5% by weight.
Claim 5
Dependent Claim
50 words
A piezoelectric/electrostrictive actuator according to any one of claims 1-4, wherein a plurality of piezoelectric/electrostrictive units (4, 6, 8, 16, 17, 22, 28) are formed on said ceramic substrate (2), such that said units are spaced from each other in a direction parallel to opposite major surfaces of said substrate.
Claim 6
Dependent Claim
39 words
A piezoelectric/electrostrictive actuator according to any one of claims 1-4, wherein a plurality of piezoelectric/electrostrictive units (4, 6, 8, 16, 17, 22, 28) are formed on said ceramic substrate (2), such that said units are superposed on each other.
Claim 7
Dependent Claim
23 words
A piezoelectric/electrostrictive actuator according to any one of claims 1-6, wherein said ceramic substrate (2) has a thickness of no more than 100µm.
Claim 8
Dependent Claim
69 words
A piezoelectric/electrostrictive actuator according to any one of claims 1-7, wherein at least said first electrode film (4, 22) or said electrode film strips (16) includes at least one major component selected from the group consisting of: noble metals which consist of platinum, palladium and rhodium and which have a high melting point; alloys including silver and palladium; alloys including silver and platinum; and alloys including platinum and palladium.
Claim 9
Dependent Claim
27 words
A piezoelectric/electrostrictive actuator according to any one of claims 1-8, wherein the grain boundaries (26) in an entire portion of said ceramic substrate (2) contain lead element.
Claim 10
Dependent Claim
32 words
A piezoelectric/electrostrictive actuator according to any one of claims 1-9, wherein the grain boundaries (26) in said selected portion of said ceramic substrate (2) contain lead in the form of an oxide.
Claim 11
Dependent Claim
23 words
A piezoelectric/electrostrictive actuator according to any one of claims 1-10, which has a piezoelectric constant |d₃₁| of at least 50 x 10⁻¹² C/N.
Claim 12
Independent Claim
43 words
A method of making a piezoelectric/electrostrictive actuator comprising arranging piezoelectric/electrostrictive film (6,17,28) between electrode films (4,8,16,22) therefor on a ceramic substrate (2), characterised by incorporating lead in grain boundaries (26) of the ceramic substrate at least in regions where said films are disposed.
References Cited (Backward Citations)
EP0257929A2
Cited
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