Title:
弾性境界波装置
Document Type and Number:
Japanese Patent JP4894861
Kind Code:
B2
Abstract:
A boundary acoustic wave device capable of effectively suppressing a high order mode spurious response with a relatively simple structure is provided. A boundary acoustic wave device (1) includes an IDT electrode (5) between a piezoelectric layer (2) and a dielectric layer (3). A low thermal expansion medium layer (4) made of a material having a linear thermal expansion coefficient less than that of the piezoelectric layer (2) is laminated on a surface of the piezoelectric layer 2 opposite to the boundary. Acoustic velocities of transversal waves in a boundary acoustic wave propagation direction at the piezoelectric layer (2), the dielectric layer (3), and the low thermal expansion medium layer (4) satisfy Expression (1), and when » represents a wavelength of the IDT electrode (5), (an acoustic velocity of a transverse wave at the dielectric layer)/» satisfies Expression (2) as follows: acoustic velocity of transverse wave at dielectric layer < acoustic velocity of SH wave at piezoelectric layer < acoustic velocity of transverse wave at low thermal expansion medium layer response frequency of boundary acoustic wave < acoustic velocity of transverse wave at dielectric layer / » < response frequency of high order mode
Inventors:
Hajime Kondo
Application Number:
JP2008550998A
Publication Date:
March 14, 2012
Filing Date:
November 21, 2007
Export Citation:
Assignee:
MURATA MANUFACTURING CO.,LTD.
International Classes:
H03H9/145
Domestic Patent References:
| JPH0548383A | 1993-02-26 | |||
| JP2004343359A | 2004-12-02 |
Foreign References:
| WO2004070946A1 | 2004-08-19 | |||
| WO2006114930A1 | 2006-11-02 | |||
| WO2005069485A1 | 2005-07-28 | |||
| WO2005099091A1 | 2005-10-20 |
Attorney, Agent or Firm:
宮▲崎▼ 主税