Multilayer piezoelectric device

Patent metadata

Field	Value
Publication number	US-9450168-B2
Application number	US-201514720062-A
Country	US
Kind code	B2
Filing date	May 22, 2015
Priority date	May 26, 2014
Publication date	Sep 20, 2016
Grant date	Sep 20, 2016

Abstract

A multilayer piezoelectric device comprises a multilayer body and first and second outer electrodes. The multilayer body has base, first and second driving parts, and non-driving part. The driving parts and non-driving part extend from the base along stacking direction. The first driving part is closer to the non-driving part than the second driving part. Each driving part has first and second inner electrodes opposing each other in stacking direction. The base has a third inner electrode extending along a plane orthogonal to the stacking direction. The first outer electrode is connected to the first inner electrode. The second outer electrode is connected to the second and third inner electrodes. In the stacking direction, the overlap area of the third and second inner electrode of the first driving part is greater than the overlap area of the third and second inner electrode of the second driving part.

First claim

What is claimed is:

1. A multilayer piezoelectric device comprising:
a multilayer body formed from a plurality of piezoelectric layers stacked along a first direction, and having a base, a non-driving part and first and second driving parts, wherein the non-driving part and first and second driving parts extend in the same first direction from the base; and
first and second outer electrodes arranged on a surface of the multilayer body while being electrically insulated from each other;
wherein the first and second driving parts and non-driving part align along a second direction orthogonal to the first direction such that the first driving part is closer to the non-driving part than is the second driving part;
wherein each of the first and second driving parts has first and second inner electrodes opposing each other in the first direction through the piezoelectric layer interposed therebetween;
wherein the base has a third inner electrode extending along a plane orthogonal to the first direction;
wherein the first inner electrode is electrically connected to the first outer electrode but electrically insulated from the second outer electrode;
wherein the second and third inner electrodes are electrically connected to the second outer electrode but electrically insulated from the first outer electrode;
wherein the second inner electrodes of the first and second driving parts are each adjacent to the third inner electrode in the first direction and partly overlap the third inner electrode as seen in the first direction; and
wherein a first area where the third inner electrode and the second inner electrode of the first driving part overlap each other is greater than a second area where the third inner electrode and the second inner electrode of the second driving part overlap each other as seen in the first direction.

2. A multilayer piezoelectric device comprising:
a multilayer body formed from a plurality of piezoelectric layers stacked along a first direction, and having a base, first and second non-driving parts and first and second driving parts, wherein the first and second non-driving parts and first and second driving parts extend in the same first direction from the base; and
first and second outer electrodes arranged on a surface of the multilayer body while being electrically insulated from each other;
wherein the first and second driving parts align along the second direction so as to be between the first and second non-driving parts;
wherein, when a middle position is a point separated from the first and second non-driving parts by the same distance on a virtual line extending in a second direction orthogonal to the first direction, the first driving part is closer to the first non-driving part than is the second driving part, while the second driving part is closer to the middle position than is the first driving part;
wherein each of the first and second driving parts has first and second inner electrodes opposing each other in the first direction through the piezoelectric layer interposed therebetween;
wherein the base has a third inner electrode extending along a plane orthogonal to the first direction;
wherein the first inner electrode is electrically connected to the first outer electrode but electrically insulated from the second outer electrode;
wherein the second and third inner electrodes are electrically connected to the second outer electrode but electrically insulated from the first outer electrode;
wherein the second inner electrodes of the first and second driving parts are each adjacent to the third inner electrode in the first direction and partly overlap the third inner electrode as seen in the first direction; and
wherein a first area where the third inner electrode and the second inner electrode of the first driving part overlap each other is greater than a second area where the third inner electrode and the second inner electrode of the second driving part overlap each other as seen in the first direction.

3. A multilayer piezoelectric device comprising:
a multilayer body formed from a plurality of piezoelectric layers stacked along a first direction, and having a base, a non-driving part and first to third driving parts, wherein the non-driving part and first and third driving parts extend in the same first direction from the base; and
first and second outer electrodes arranged on a surface of the multilayer body while being electrically insulated from each other;
wherein the first to third driving parts and non-driving part align along a second direction orthogonal to the first direction such that the first to third driving parts sequentially increase distance to the non-driving part;
wherein each of the first to third driving parts has first and second inner electrodes opposing each other in the first direction through the piezoelectric layer interposed therebetween;
wherein the base has a third inner electrode extending along a plane orthogonal to the first direction;
wherein the first inner electrode is electrically connected to the first outer electrode but electrically insulated from the second outer electrode;
wherein the second and third inner electrodes are electrically connected to the second outer electrode but electrically insulated from the first outer electrode;
wherein the second inner electrodes of the first to third driving parts are each adjacent to the third inner electrode in the first direction and partly overlap the third inner electrode as seen in the first direction; and
wherein first to third areas where the third inner electrode overlaps the respective second inner electrodes of the first to third driving parts as seen in the first direction decrease sequentially.

4. The multilayer piezoelectric device according to claim 3 , wherein, as seen in the first direction, in a third direction orthogonal to both of the first and second directions, the third inner electrode has a width increasing toward the non-driving part.

5. A multilayer piezoelectric device comprising:
a multilayer body formed from a plurality of piezoelectric layers stacked along a first direction, and having a base, first and second non-driving parts and first to third driving parts, wherein the first and second non-driving parts and first and third driving parts extend in the same first direction from the base; and
first and second outer electrodes arranged on a surface of the multilayer body while being electrically insulated from each other;
wherein, when a middle position is a point separated from the first and second non-driving parts by the same distance on a virtual line extending in a second direction orthogonal to the first direction, the first to third driving parts align along the second direction sequentially from the first non-driving part toward the middle position;
wherein each of the first to third driving parts has first and second inner electrodes opposing each other in the first direction through the piezoelectric layer interposed therebetween;
wherein the base has a third inner electrode extending along a plane orthogonal to the first direction;
wherein the first inner electrode is electrically connected to the first outer electrode but electrically insulated from the second outer electrode;
wherein the second and third inner electrodes are electrically connected to the second outer electrode but electrically insulated from the first outer electrode;
wherein the second inner electrodes of the first to third driving parts are each adjacent to the third inner electrode in the first direction and partly overlap the third inner electrode as seen in the first direction; and
wherein first to third areas where the third inner electrode overlaps the respective second inner electrodes of the first to third driving parts as seen in the first direct

Assignees

• Tdk Corp

Inventors

• Satoh Yasuyuki
• Itakura Keisuke
• Sugawara Jun

Classifications

• H01L41/0836 Primary

  Electricity · mapped topic

• H01L41/0471

  Electricity · mapped topic

• H10N30/871 Primary

  Single-layered electrodes of multilayer piezoelectric or electrostrictive devices, e.g. internal electrodes · CPC title

• H10N30/50

  having a stacked or multilayer structure · CPC title

• H10N30/506 Primary

  having a cylindrical shape and having stacking in the radial direction, e.g. coaxial or spiral type rolls · CPC title