| US 7,589,451 B2 | ||
| Surface acoustic wave device | ||
| Takao Morita, Kouza-gun (Japan); and Takuya Ohwaki, Kouza-gun (Japan) | ||
| Assigned to Epson Toyocom Corporation, Tokyo (Japan) | ||
| Appl. No. 10/594,982 PCT Filed Mar. 08, 2005, PCT No. PCT/JP2005/003998 § 371(c)(1), (2), (4) Date Sep. 29, 2006, PCT Pub. No. WO2005/099089, PCT Pub. Date Oct. 20, 2005. |
||
| Claims priority of application No. 2004-108608 (JP), filed on Apr. 01, 2004; and application No. 2004-310452 (JP), filed on Oct. 26, 2004. | ||
| Prior Publication US 2007/0194657 A1, Aug. 23, 2007 | ||
| Int. Cl. H03H 9/125 (2006.01); H03H 9/25 (2006.01) | ||
| U.S. Cl. 310—313R [333/195] | 16 Claims |
| 1. A surface acoustic wave device comprising a piezoelectric substrate and an IDT that is formed on said piezoelectric substrate
and is made from Al or alloy including Al as a main component, an excited wave being an SH wave, wherein
said piezoelectric substrate is a rotation Y cut substrate made from a quartz flat substrate,
where a cut angle θ of said piezoelectric substrate is a rotation angle of a crystal Z-axis when piezoelectric substrate is
rotated around a crystal X-axis,
a direction in which the piezoelectric substrate is rotated from a positive Z-axis side to a positive Y-axis side is a direction
in which said cut angle θ is minus, and
the cut angle θ is set in a range of −64.0°<θ<−49.3°, and a propagation direction of a SAW is set to (90°±5°) to a crystal
X-axis, and
when a wavelength of the SAW to be excited is represented as λ, an electrode film thickness H/λ standardized by a wavelength
of said IDT is set to satisfy 0.04<H/λ<0.12.
|