At-cut crystal element and crystal resonator

Patent metadata

Field	Value
Publication number	US-10637437-B2
Application number	US-201615559831-A
Country	US
Kind code	B2
Filing date	Mar 17, 2016
Priority date	Apr 15, 2015
Publication date	Apr 28, 2020
Grant date	Apr 28, 2020

Abstract

An AT-cut crystal element is provided for reducing unnecessary vibration and for improving impedance of a resonator. Two side surfaces intersecting with a Z′-axis of a crystallographic axis of crystal are constituted of three surfaces of a first surface as an m-surface of quartz crystal, a second surface that intersects with the first surface and is other than the m-surface, and a third surface that intersects with the second surface and is other than the m-surface. Moreover, the second surface is a surface corresponding to a surface obtained by rotating a principal surface of the AT-cut crystal element by −74±3° having an X-axis of crystal as a rotation axis, and the third surface is a surface corresponding to a surface obtained by rotating the principal surface by −56±3° having the X-axis of the crystal as the rotation axis.

First claim

The invention claimed is:

1. An AT-cut crystal element, comprising:
side surfaces that intersect with a Z′-axis of a crystallographic axis of crystal,
at least one side surface of the side surfaces being constituted of three surfaces of a first surface, a second surface, and a third surface, wherein
the first surface being an m-surface of a quartz crystal,
the second surface intersecting with the first surface and being other than the m-surface,
the third surface intersecting with the second surface and being other than the m-surface.

2. The AT-cut crystal element according to claim 1 , wherein
the second surface is a surface corresponding to a surface obtained by rotating an X-Z′-surface which is a principle surface of the AT-cut crystal element indicated by a crystallographic axis of the crystal by −74±5° having an X-axis of the crystal as a rotation axis, and
the third surface is a surface corresponding to a surface obtained by rotating the principal surface by −56±5° having the X-axis of the crystal as the rotation axis.

3. The AT-cut crystal element according to claim 1 , wherein
the second surface is a surface corresponding to a surface obtained by rotating an X-Z′-surface which is a principle surface of the AT-cut crystal element indicated by a crystallographic axis of the crystal by −74±3° having an X-axis of the crystal as a rotation axis, and
the third surface is a surface corresponding to a surface obtained by rotating the principal surface by −56±3° having the X-axis of the crystal as the rotation axis.

4. The AT-cut crystal element according to claim 1 , wherein
the AT-cut crystal element has a planar shape in a rectangular shape, and has one side along the Z′-axis.

5. The AT-cut crystal element according to claim 1 , wherein
each of both side surfaces is constituted of three surfaces of the first surface to the third surface.

6. The AT-cut crystal element according to claim 1 , wherein
the both side surfaces are in a relation of point symmetry one another having a center point of the AT-cut crystal element as a center.

7. The AT-cut crystal element according to claim 1 , wherein
the AT-cut crystal element is a crystal element that includes a first region and a second region,
the first region has a first thickness, and
the second region has a second thickness thinner than the first thickness and is formed continuous with the first region on an outside of the first region.

8. A crystal resonator, comprising:
the crystal element according to claim 1 ;
an excitation electrode, disposed on front and back of the crystal element; and
an extraction electrode, extracted from the excitation electrode.

9. A crystal unit, comprising:
the crystal resonator according to claim 8 ; and
a container, housing the crystal resonator.

Assignees

• Nihon Dempa Kogyo Co

Inventors

• Yamauchi Hiroyuki
• Osawa Kazuhiko
• Takeda Shohei

Classifications

• H03H2003/0435

  of a piezoelectric layer · CPC title

• H03H9/10

  Mounting in enclosures {(constructional combinations of enclosure with electromechanical and other electronic elements H03H9/0538)} · CPC title

• H03H9/132 Primary

  characterized by a particular shape · CPC title

• H03H9/02023

  consisting of quartz · CPC title

• H03H9/19 Primary

  consisting of quartz · CPC title