The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 04, 2002
Filed:
May. 19, 2000
Kenji Inoue, Tokyo, JP;
Tsuguo Fukuda, Sendai, JP;
Katsuo Sato, Tokyo, JP;
Hiroki Morikoshi, Tokyo, JP;
Katsumi Kawasaki, Tokyo, JP;
Kiyoshi Uchida, Tokyo, JP;
TDK Corporation, Tokyo, JP;
Abstract
The present invention provides a piezoelectric substrate for a surface acoustic wave device which has high electromechanical coupling coefficient and low SAW velocity, and a surface acoustic wave device using the same. The present invention applies a single crystal comprising belonging to a point group 32 and having Ca Ga Ge O type crystal structure. The basic component of the single crystal is comprised of La, Sr, Ta, Ga and O and is represented by the chemical formula: La Sr Ta Ga O . The composition ratio of Sr is preferably in the range of 0x≦0.15, and more preferably in the range of 0.07x≦0.08. The present invention also provides a surface acoustic wave device using that in which an interdigital finger electrode is formed in one main surface of the aforementioned piezoelectric substrate. When a cut angle of the substrate cut out of the single crystal and a propagation direction of surface acoustic waves are represented in terms of Euler angles (&phgr;, &thgr;, &psgr;), adequate characteristics can be obtained by selecting these angles.