Resonator and resonance device

Patent metadata

Field	Value
Publication number	US-10673402-B2
Application number	US-201816174563-A
Country	US
Kind code	B2
Filing date	Oct 30, 2018
Priority date	May 25, 2016
Publication date	Jun 2, 2020
Grant date	Jun 2, 2020

Abstract

A resonator that includes a base and one or more vibration arms with fixed ends connected to a front end of the base and open ends extending therefrom. Moreover, the vibration arms include first and second electrodes and a piezoelectric film that is disposed therebetween. The resonator further includes a protective film disposed opposing an upper face of the piezoelectric film and sandwiching the first electrode and a temperature characteristics adjusting film formed of a material different from a material of the protective film and that is provided on the fixed end side relative to the center of the vibration arms such that part of the protective film is exposed to a surface.

First claim

The invention claimed is:

1. A resonator comprising:
a base;
at least one vibration arm having a fixed end connected to a front end of the base and an open end extending from the front end, the vibration arm including first and second electrodes with a piezoelectric film disposed therebetween and having an upper face opposite the first electrode;
a protective film disposed opposing the upper face of the piezoelectric film and sandwiching the first electrode therebetween; and
a temperature characteristics adjusting film comprising a material different than a material of the protective film and disposed on a fixed end side of the at least one vibration arm relative to a center of the at least one vibration arm, such that a least a portion of the protective film on the at least one vibration arm is exposed to a surface.

2. The resonator according to claim 1 , wherein the at least one vibration arm is configured to vibrate in a predetermined vibration mode when a voltage is applied between the first and second electrodes.

3. The resonator according to claim 1 , wherein the protective film extends from the fixed end of at least one vibration arm towards the open end.

4. The resonator according to claim 1 , further comprising a frequency adjusting film opposing the upper face of the piezoelectric film with the protective film interposed between the frequency adjusting film and the upper face of piezoelectric film.

5. The resonator according to claim 4 , wherein the frequency adjusting film is disposed separately from the temperature characteristics adjusting film at a position including the open end of the at least one vibration arm, such that the protective film is exposed between the frequency adjusting film and the temperature characteristics adjusting film.

6. The resonator according to claim 4 , wherein the frequency adjusting film comprises a material having mass reduction rate due to etching that is higher than a mass reduction rate of the protective film.

7. The resonator according to claim 6 , wherein the temperature characteristics adjusting film comprises a same material as the material of the frequency adjusting film.

8. The resonator according to claim 4 , wherein the frequency adjusting film comprises one of molybdenum, tungsten, gold, platinum, and nickel.

9. The resonator according to claim 1 , wherein the protective film is an insulator and the temperature characteristics adjusting film is a metal.

10. The resonator according to claim 1 , further comprising:
a frame that at least partially surrounds a periphery of the base and the at least one vibration arm, and
a holding arm connecting the base to the holding section.

11. A resonance device comprising:
the resonator according to claim 1 ;
a lid members configured to cover the resonator; and
an outer electrode.

12. A resonator comprising:
a base;
at least one vibration arm extending from the base and including first and second electrodes with a piezoelectric film disposed therebetween;
a protective film disposed on an outer surface of one of the first and second electrodes; and
a temperature characteristics adjusting film comprising a material different than a material of the protective film,
wherein the temperature characteristics adjusting film is disposed on at least one of the base and the at least one vibration arm, such that a least a portion of the protective film disposed on the outer surface of the one of the first and second electrodes is exposed.

13. The resonator according to claim 12 , wherein the protective film extends from the base towards an open end of the at least one vibration arm.

14. The resonator according to claim 12 , further comprising a frequency adjusting film disposed on at least one of the first and second electrodes of the at least one vibration arm, such that the protective film is interposed between the frequency adjusting film and the one of the first and second electrodes.

15. The resonator according to claim 14 , wherein the frequency adjusting film is disposed separately from the temperature characteristics adjusting film at a position including an open end of the at least one vibration arm opposite the base, such that the protective film is exposed between the frequency adjusting film and the temperature characteristics adjusting film.

16. The resonator according to claim 14 , wherein the frequency adjusting film comprises a material having mass reduction rate due to etching that is higher than a mass reduction rate of the protective film.

17. The resonator according to claim 16 , wherein the temperature characteristics adjusting film comprises a same material as the material of the frequency adjusting film.

18. The resonator according to claim 15 , wherein the frequency adjusting film comprises one of molybdenum, tungsten, gold, platinum, and nickel.

19. The resonator according to claim 12 , wherein the protective film is an insulator and the temperature characteristics adjusting film is a metal.

20. The resonator according to claim 12 , further comprising:
a frame that at least partially surrounds a periphery of the base and the at least one vibration arm, and
a holding arm connecting the base to the holding section.

21. The resonator according to claim 12 , wherein the at least one arm comprises a weight disposed on an open end thereof, the weight have a greater width than the at least one arm and having a frequency adjusting film disposed thereon.

Assignees

• Murata Manufacturing Co

Inventors

• Inoue Yoshihisa
• Nishimura Toshio
• Takeyama Keisuke
• Kawai Ryota
• Goto Yuichi

Classifications

• H03H9/02102 Primary

  of temperature influence (cutting angles H03H9/02015) · CPC title

• H03H2009/155

  using MEMS techniques · CPC title

• H03H9/0595 Primary

  the holder support and resonator being formed in one body · CPC title

• H03H9/02393

  Post-fabrication trimming of parameters, e.g. resonance frequency, Q factor · CPC title

• H03H9/176

  consisting of ceramic material (H03H9/177, H03H9/178 take precedence) · CPC title