Ceramic device

• US 6,998,763 B2
• Filed: 08/29/2002
• Issued: 02/14/2006
• Est. Priority Date: 08/31/2001
• Status: Expired due to Fees

• Current Assignee: NGK Insulators Limited
• Original Assignee: NGK Insulators Limited
• Inventors: Kimura, Koji, Takeuchi, Yukihisa, Nanataki, Tsutomu, Takahashi, Masao
• Primary Examiner(s): BUDD, MARK OSBORNE
• Application Number:
  US10/230,731
• Publication Number:
  US 20030062807A1
• Time in Patent Office: 1,265 Days
• Field of Search: 310/364, 310/328, 310/338, 310/331
• US Class Current: 310/364
• CPC Class Codes: B81B 3/0035 Constitution or structural means for controlling the movement of the flexible or deformable elements
• CPC Class Codes: G01P 15/09 by piezoelectric pick-up
• CPC Class Codes: H03H 9/02133 of stress
• CPC Class Codes: H03H 9/105 the enclosure being defined by a cover cap mounted on an element forming part of the BAW device
• CPC Class Codes: H03H 9/12 for networks with interaction of optical and acoustic waves
• CPC Class Codes: H03H 9/132 characterized by a particular shape
• CPC Class Codes: H03H 9/173 Air-gaps
• CPC Class Codes: H03H 9/176 consisting of ceramic material H03H9/177, H03H9/178 take precedence
• CPC Class Codes: H10N 30/2047 Membrane type
• CPC Class Codes: H10N 30/877 Conductive materials in general H01B1/00

Abstract

A ceramic device has an actuator element which includes a shape-retaining layer, an upper electrode formed on an upper portion of the shape-retaining layer, and a lower electrode formed on a lower portion of the shape-retaining layer. A vibrating section of ceramics supports the actuator element and a fixed section of ceramics vibratingly supports the vibrating section. An electrode material of the lower electrode contacting the vibrating section contains an additive in an amount of 0.01% by weight to 20% by weight. The electrode material contains platinum as a major component, for example. The additive to the electrode material is preferably zirconium oxide, cerium oxide, or titanium oxide.

Claims

1. A ceramic device comprising:

an operating section having at least a pair of electrodes formed on a shape-retaining layer, said shape-retaining layer comprising one of a piezoelectric/electrostrictive layer and an anti-ferroelectric layer;

a vibrating section comprising a ceramic supporting said operating section, at least one electrode of said electrodes contacting said vibrating section; and

a fixed section comprising a ceramic vibratingly supporting said vibrating section;

wherein said vibrating section, said electrode contacting said vibrating section, and said shape-retaining layer are integrally fired; and

wherein at least said electrode contacting said vibrating section comprises an electrode material containing a minute amount of an additive having an average particle diameter of 0.01 to 1.0 μ

m when said additive is at least one material selected from the group consisting of zirconium oxide, cerium oxide, and hafnium oxide;

wherein said additive has an average particle diameter of 0.1 to 10.0 μ

m when said additive is at least one material selected from the group consisting of titanium oxide, the material of the piezoelectric/electrostrictive layer, and the material of the anti-ferroelectric layer; and

wherein said additive is contained in said electrode material in an amount of 0.1 wt % to 5 wt %.

2. The ceramic device according to claim 1, wherein said ceramic material is at least one material selected from the group consisting of zirconium oxide, cerium oxide, and titanium oxide.

3. The ceramic device according to claim 1, wherein said pair of electrodes includes an upper electrode formed on an upper portion of said shape-retaining layer and a lower electrode formed between said shape-retaining layer and said vibrating section.

4. The ceramic device according to claim 3, wherein said electrode material of said lower electrode contains said minute amount of said additive.

5. The ceramic device according to claim 1, wherein said pair of electrodes contact said vibrating section.

6. The ceramic device according to claim 1, wherein at least said electrode contacting said vibrating section comprises said electrode material containing an element of the platinum group, an alloy of said element of the platinum group and gold and/or silver, an alloy of elements of the platinum group, or an alloy of said alloy of said element of the platinum group and gold and/or silver.

7. The ceramic device according to claim 6, wherein said electrode material contains platinum as a major component.

8. The ceramic device according to claim 1, wherein an object restricting a displacement action of said operating section is formed on said operating section.