US-12620968-B2 - Quartz crystal resonator, quartz crystal resonator unit and quartz crystal oscillator

Abstract

A quartz crystal resonator that includes a quartz crystal element having main surfaces extending in a plane φ degrees around a Z axis of the quartz crystal element and θ degrees around an X′ axis of the quartz crystal element; and an electrode in contact with the quartz crystal element, where x=t/T≥0.01, |φ−(−98.6x 3 +114.0x 2 −22.3x+1.3)|≤5 and |θ−(−9.5x 3 −10.9x 2 +1.4x+35.3)|≤0.5, wherein T is a thickness of the quartz crystal element and t is a thickness of the electrode.

Inventors

• Toshio Nishimura

Assignees

• MURATA MANUFACTURING CO., LTD.

Dates

Publication Date

20260505

Application Date

20220908

Priority Date

20200319

Claims (20)

1. 1 . A quartz crystal resonator, comprising: a quartz crystal element having main surfaces extending in a plane φ degrees around a Z axis of the quartz crystal element and θ degrees around an X′ axis of the quartz crystal element; and an electrode in contact with the quartz crystal element, where x=t/T≥ 0.01, 0<φ, |φ−(−98.6 x 3+114.0 x 2 −22.3 x+ 1.3)|≤5, and |θ−(−9.5 x 3 -10.9 x 2 +1.4 x+ 35.3)|≤0.5, wherein T is a thickness of the quartz crystal element and t is a thickness of the electrode.
2. 2 . The quartz crystal resonator according to claim 1 , wherein 0.02≤t/T.
3. 3 . The quartz crystal resonator according to claim 2 , wherein 0.05≤t/T.
4. 4 . The quartz crystal resonator according to claim 3 , wherein 0.1≤t/T.
5. 5 . The quartz crystal resonator according to claim 1 , wherein t/T≤0.5.
6. 6 . The quartz crystal resonator according to claim 1 , wherein the thickness t is a sum of thicknesses of a pair of electrodes on the main surfaces of the quartz crystal element.
7. 7 . The quartz crystal resonator according to claim 1 , wherein a main vibration of the quartz crystal resonator is a thickness shear vibration mode.
8. 8 . The quartz crystal resonator according to claim 1 , wherein the electrode comprises aluminum.
9. 9 . A quartz crystal resonator unit, comprising: the quartz crystal resonator according to claim 1 ; a base member; and a lid member bonded to the base member, wherein the quartz crystal resonator is in an internal space between the base member and the lid member.
10. 10 . A quartz crystal oscillator, comprising: the quartz crystal resonator unit according to claim 1 ; and an IC chip operatively connected to the quartz crystal resonator unit, the IC chip including an oscillation circuit of the quartz crystal resonator unit.
11. 11 . A quartz crystal resonator, comprising: a quartz crystal element having main surfaces extending in a plane φ degrees around a Z axis of the quartz crystal element and θ degrees around an X′ axis of the quartz crystal element; and an electrode in contact with the quartz crystal element, where x=t/T≥ 0.01, 0<φ, and |φ−(−0.017θ 3 +1.37θ 2 -37.6θ+351)|≤5, wherein T is a thickness of the quartz crystal element and t is a thickness of the electrode.
12. 12 . The quartz crystal resonator according to claim 11 , wherein 0.02≤t/T.
13. 13 . The quartz crystal resonator according to claim 12 , wherein 0.05≤t/T.
14. 14 . The quartz crystal resonator according to claim 13 , wherein 0.1≤t/T.
15. 15 . The quartz crystal resonator according to claim 11 , wherein t/T≤0.5.
16. 16 . The quartz crystal resonator according to claim 11 , wherein the thickness t is a sum of thicknesses of a pair of electrodes on the main surfaces of the quartz crystal element.
17. 17 . The quartz crystal resonator according to claim 11 , wherein a main vibration of the quartz crystal resonator is a thickness shear vibration mode.
18. 18 . The quartz crystal resonator according to claim 11 , wherein the electrode comprises aluminum.
19. 19 . A quartz crystal resonator unit, comprising: the quartz crystal resonator according to claim 11 ; a base member; and a lid member bonded to the base member, wherein the quartz crystal resonator is in an internal space between the base member and the lid member.
20. 20 . A quartz crystal oscillator, comprising: the quartz crystal resonator unit according to claim 19 ; and an IC chip operatively connected to the quartz crystal resonator unit, the IC chip including an oscillation circuit of the quartz crystal resonator unit.

Description

CROSS REFERENCE TO RELATED APPLICATIONS The present application is a continuation of International application No. PCT/JP2020/041942, filed Nov. 10, 2020, which claims priority to Japanese Patent Application No. 2020-049701, filed Mar. 19, 2020, the entire contents of each of which are incorporated herein by reference TECHNICAL FIELD The present invention relates to a quartz crystal resonator, a quartz crystal resonator unit and a quartz crystal oscillator. BACKGROUND ART Resonator units are used in various electronic devices such as mobile communication terminals, communication base stations, and home appliances for applications such as timing devices, sensors, and oscillators, etc. As electronic devices become more functional, smaller and thinner resonators are required. Patent Document 1 discloses a double-rotation Y-cut quartz crystal resonator having favorable frequency-temperature characteristics in a region on a temperature side higher than room temperature. Patent Document 1: Patent Publication JP-A-2003-324332 SUMMARY In the case of a low-frequency quartz crystal resonator, since the thickness of a quartz crystal element is large, and the ratio of the thickness of an electrode to the thickness of the quartz crystal element is small, the influence on the electrode is negligible in consideration of frequency-temperature characteristics. However, in the case of a high-frequency quartz crystal resonator, since the thickness of the quartz crystal element is small, the ratio of the thickness of the electrode to that of the quartz crystal element is large, and the electrode influences frequency-temperature characteristics. Therefore, frequency-temperature characteristics of the quartz crystal resonator described in Patent Document 1 and the AT-cut quartz crystal resonator may deteriorate in a high frequency range. The present invention has been made in view of such circumstances, and an object of the present invention is to provide a quartz crystal resonator, a quartz crystal resonator unit and a quartz crystal oscillator which have favorable frequency-temperature characteristics. A quartz crystal resonator according to one aspect of the present invention includes a quartz crystal element having main surfaces extending in a plane φ degrees around a Z axis of the quartz crystal element and θ degrees around an X′ axis of the quartz crystal element; and an electrode in contact with the quartz crystal element, where x=t/T≥0.01, |φ−(−98.6x3+114.0x2−22.3x+1.3)|≤5, and |θ−(−9.5x3−10.9x2+1.4x+35.3)|≤0.5, wherein T is a thickness of the quartz crystal element and t is a thickness of the electrode. A quartz crystal resonator according to another aspect of the present invention includes a quartz crystal element having main surfaces extending in a plane φ degrees around a Z axis of the quartz crystal element and θ degrees around an X′ axis of the quartz crystal element; and an electrode in contact with the quartz crystal element, where x=t/T≥0.01, and |φ−(−0.017θ3+1.37θ2−37.6θ+351)|≤5, wherein T is a thickness of the quartz crystal element and t is a thickness of the electrode. According to the present invention, it is possible to provide a quartz crystal resonator, a quartz crystal resonator unit and a quartz crystal oscillator which have favorable frequency-temperature characteristics. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded perspective view schematically showing a configuration of a quartz crystal oscillator according to a first embodiment. FIG. 2 is a cross-sectional view schematically showing a configuration of the quartz crystal oscillator according to the first embodiment. FIG. 3 is an exploded perspective view schematically showing a structure of a quartz crystal resonator unit according to the first embodiment. FIG. 4 is a cross-sectional view schematically showing a configuration of the quartz crystal resonator unit according to the first embodiment. FIG. 5 is a diagram showing first rotation of a quartz crystal. FIG. 6 is a diagram showing second rotation of a quartz crystal. FIG. 7 is a graph showing an optimum rotation angle of a quartz crystal element. FIG. 8 is a graph showing an optimum rotation angle of a quartz crystal element. FIG. 9 is a graph showing frequency-temperature characteristics of examples. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings. The drawings of the embodiments are examples, and sizes and shapes of respective parts are schematically shown, and the technical scope of the present invention should not be understood as limited to the embodiments. In the drawings, in order to clarify the relationship between the drawings and to help understanding the positional relationship of respective members, an orthogonal coordinate system composed of an X′ axis, a Y″ axis and a Z′ axis is used for convenience. The X′ axis, the Y″ axis and the Z′ axis correspond to each other in