STACKED PIEZOELECTRIC ELEMENT AND MULTIFEED DETECTION SENSOR

Title:

STACKED PIEZOELECTRIC ELEMENT AND MULTIFEED DETECTION SENSOR

Document Type and Number:

WIPO Patent Application WO/2013/080875

Kind Code:

A1

Abstract:

The objective of the invention is to provide a stacked piezoelectric element, wherein neither degradation of electric characteristic nor increase of acoustic wave frequency occur even through the element size is reduced, and a multifeed detection sensor. A stacked piezoelectric element (11) comprises a piezoelectric element layer (11B) and a matching layer (11A). The piezoelectric element layer (11B) has a structure in which a piezoelectric substance layer (11B2) and an electrode layer (11B1) are stacked on top of each other in multiple layers. The matching layer (11A) is stacked on the piezoelectric element layer (11B) and has an acoustic impedance different from that of the piezoelectric element layer (11B). If the acoustic velocity in the piezoelectric element layer (11B) is Vp, the acoustic velocity in the matching layer (11A) is Vm, the thickness dimension of the piezoelectric element layer (11B) is Tp, and if the thickness dimension of the matching layer (11A) is Tm, then Vp/Vm = Tp/Tm. Further, if the dimension in the width direction is W, then Tp + Tm > W.

Inventors:

NISHIE JUNICHI (JP)
KONDO CHIKASHI (JP)
OTA JUNSHI (JP)

Application Number:

PCT/JP2012/080271

Publication Date:

June 06, 2013

Filing Date:

November 22, 2012

Export Citation:

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Assignee:

MURATA MANUFACTURING CO (JP)

International Classes:

H04R17/00; B65H7/12; G01B17/02; H01L41/08; H01L41/083

Foreign References:

JP2004064381A	2004-02-26
JPH06327098A	1994-11-25
JP2005108989A	2005-04-21
JP2005123554A	2005-05-12
JPS6270707A	1987-04-01
JPH10224895A	1998-08-21

Other References: