Surface acoustic wave element, method of manufacturing the same and surface acoustic wave device
AssigneeSeiko Epson Corporation
InventorsTakashi Yamazaki, Keigo Iizawa
Life of this patent
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Abstract
A surface acoustic wave element is provided including an IDT and reflectors provided on both sides of the IDT that are on a surface of a quartz plate. The quartz plate is made from an in-plane rotated ST cut quartz plate whose cutting angle is expressed as (0°, 113°-135°, ±(40°-49°)) by defining and using Euler angle. The IDT and reflectors are arranged at a slant of PFA±3° with respect to a direction of a phase velocity of a surface acoustic wave in the quartz plate. If the cutting angle of the quartz plate is expressed by the Euler angle (φ°, θ°, Ψ°), the power flow angle PFA is expressed that the PFA=0.374 (θ°−90°)−10.0°.
Claims9
A surface acoustic wave element comprising:
- an in-plane rotated ST cut quartz plate whose cutting angle is expressed as (0°, 113°-135°(40°-49°)) by defining and using Euler angle of (φ°,θ°,Ψ°);
- an interdigital transducer;
- and
- a reflector, wherein:
- the interdigital transducer and the reflector that are formed on a surface of the quartz plate are arranged at a slant of a PFA ±3° with respect to a direction of a phase velocity of a surface acoustic wave in the quartz plate;
- the PFA is represented by the following equation:
- PFA=0.374(θ°−90°)−10.0°;
- and
- first and second opposing edges of the ST cut quartz plate are substantially parallel to a group velocity direction of the surface acoustic wave element.
A surface acoustic wave element comprising a quartz plate of which an interdigital transducer is formed on a surface and in which a direction of a phase velocity of a surface acoustic wave and a direction of a group velocity of the surface acoustic wave are different, wherein
- two opposing edges of the quartz plate face each other and are substantially parallel to the direction of the group velocity.
A surface acoustic wave element comprising a quartz plate of which an interdigital transducer is formed on a surface and in which a direction of a phase velocity of a surface acoustic wave and a direction of a group velocity of the surface acoustic wave are different, wherein:
- two edges of the quartz plate face each other along the direction of the group velocity;
- and
- the quartz plate includes two edges perpendicular to the direction of the group velocity of the surface acoustic wave.
Dependencies are inferred from the claim text.