Quartz crystal blank and quartz crystal resonator unit

Patent metadata

Field	Value
Publication number	US-10135420-B2
Application number	US-201715814866-A
Country	US
Kind code	B2
Filing date	Nov 16, 2017
Priority date	Jun 12, 2015
Publication date	Nov 20, 2018
Grant date	Nov 20, 2018

Abstract

A rectangular quartz crystal blank having long sides substantially parallel to a Z′ axis of the quartz crystal blank, and short sides substantially parallel to an X axis of the quartz crystal blank. The quartz crystal blank includes a first center region, a second region and a third region that are adjacent to the first region along a long-side direction, and a fourth region and a fifth region that are adjacent to the first region along a short-side direction. A thickness of the second region and a thickness of the third region are smaller than a thickness of the first region, and/or a thickness of the fourth region and a thickness of the fifth region are smaller than the thickness of the first region, and 19.87≤W/T≤20.36, where W is a length of a short side and T is a thickness.

First claim

The invention claimed is:

1. An AT-cut quartz crystal blank comprising:
a quartz crystal body that is rectangular in shape in a direction normal to a main surface thereof, the quartz crystal body having a first region including a center of the main surface in the direction normal to the main surface, a second region and a third region that are adjacent to the first region on opposed sides thereof along a long-side direction in which long sides of the quartz crystal body extend, and a fourth region and a fifth region that are adjacent to the first region on opposed sides thereof along a short-side direction in which short sides of the quartz crystal body extend,
wherein the long sides of the main surface are substantially parallel to a Z′ axis of the quartz crystal blank,
wherein the short sides of the main surface are substantially parallel to an X axis of the quartz crystal blank,
wherein a frequency of a main vibration of the quartz crystal blank is in a range of 50.0 MHz to 54.0 MHz,
wherein a thickness of the first region is substantially uniform,
wherein at least one of (1) a thickness of the second region and a thickness of the third region are smaller than the thickness of the first region, and (2) a thickness of the fourth region and a thickness of the fifth region are smaller than the thickness of the first region, and
wherein 19.87≤W/T≤20.36, where W is a length of the first region, the fourth region, and the fifth region along the short-side direction, and T is the thickness of the first region.

2. The quartz crystal blank according to claim 1 , wherein 19.93≤W/T≤20.33.

3. The quartz crystal blank according to claim 1 , wherein the thickness of the second region and the thickness of the third region are smaller than the thickness of the first region, and the thickness of the fourth region and the thickness of the fifth region are smaller than the thickness of the first region.

4. The quartz crystal blank according to claim 1 , wherein the thickness of the second region and the thickness of the third region are smaller than the thickness of the first region.

5. The quartz crystal blank according to claim 1 , wherein the thickness of the fourth region and the thickness of the fifth region are smaller than the thickness of the first region.

6. The quartz crystal blank according to claim 3 ,
wherein the second region and the third region are positioned at opposed ends of the quartz crystal blank in the long-side direction, and
wherein the fourth region and the fifth region are positioned at opposed ends of the quartz crystal blank in the short-side direction.

7. The quartz crystal blank according to claim 6 , wherein a thickness of the quartz crystal blank decreases with increasing distance from the center of the main surface in the long-side direction and decreases with increasing distance from the center of the main surface in the short-side direction.

8. The quartz crystal blank according to claim 6 , wherein a thickness of the quartz crystal blank decreases with increasing distance from the center of the main surface in the long-side direction.

9. The quartz crystal blank according to claim 6 , wherein a thickness of the quartz crystal blank decreases with increasing distance from the center of the main surface in the short-side direction.

10. The quartz crystal blank according to claim 6 ,
wherein 0.69≤RL/L≤0.95, where L is a length of the first region, the second region, and the third region along the long-side direction, and RL is a length of the first region along the long-side direction, and
wherein 0.71≤RW/W≤0.95, where RW is a length of the first region along the short-side direction.

11. The quartz crystal blank according to claim 10 ,
wherein 0.69≤RL/L≤0.83, and
wherein 0.71≤RW/W≤0.84.

12. A quartz crystal resonator unit comprising:
the quartz crystal blank according to claim 1 .

13. The quartz crystal resonator unit according to claim 12 , further comprising:
a first outer electrode and a second outer electrode that are each arranged along a respective short side of the quartz crystal blank;
a substrate body; and
a third outer electrode and a fourth outer electrode that are each disposed on a respective main surface of the substrate body,
wherein the first outer electrode and the third outer electrode are electrically connected to each other, and the second outer electrode and the fourth outer electrode are electrically connected to each other.

14. The quartz crystal resonator unit according to claim 13 , further comprising:
a cap disposed on the substrate body and covering the quartz crystal resonator.

Assignees

• Murata Manufacturing Co

Inventors

• Ibaragi Hiroshi
• Yamamoto Hiroyuki
• Kawai Ryuichi

Classifications

• H03H9/19 Primary

  consisting of quartz · CPC title

• H03H9/177

  of the energy-trap type · CPC title

• H03H3/02

  for the manufacture of piezoelectric or electrostrictive resonators or networks (H03H3/08 takes precedence) · CPC title

• H03H9/1021

  the BAW device being of the cantilever type · CPC title

• H03H2003/022

  the resonators or networks being of the cantilever type · CPC title