Vibrator Element And Vibrator Device

A vibrator element includes a vibrating section having a rectangular shape in a plan view and including a first principal surface, a second principal surface, and an excitation portion sandwiched by a first excitation electrode and a second excitation electrode and making a thickness-shear vibration, a coupling arm extending from a corner part of the vibrating section in a first direction, and a supporting arm having a side surface at one end part side coupled to the coupling arm and extending in a second direction crossing the first direction, wherein the supporting arm includes a first supporting electrode electrically coupled to the first excitation electrode and bonded to a container via an adhesive member, and a width of the coupling arm along the second direction is four or more times a thickness of the excitation portion along a third direction crossing the first direction and the second direction and equal to or smaller than a length from an end part of the supporting arm at the coupling arm side to the first supporting electrode along the second direction.

The present application is based on, and claims priority from JP Application Serial Number 2022-183126, filed Nov. 16, 2022, the disclosure of which is hereby incorporated by reference herein in its entirety.

BACKGROUND

1. Technical Field

The present disclosure relates to a vibrator element and a vibrator device.

2. Related Art

JP-A-2015-186196 discloses a piezoelectric vibrator element including a vibrating section on which a pair of excitation electrodes are provided, a supporting portion extending apart from the vibrating section, and a coupling portion extending to couple one end of the supporting portion and an end part of the vibrating section, wherein extraction electrodes are respectively extracted from the pair of excitation electrodes to a joint surface of the supporting portion. According to the configuration, an influence on a vibration by supporting stress is suppressed.

In the piezoelectric vibrator element in JP-A-2015-186196, an influence on a thickness-shear vibration as a main vibration by supporting stress may be suppressed, however, no consideration is taken for the width of the coupling portion for effective isolation of a spurious vibration. Accordingly, vibration characteristics of the main vibration may be degraded by the spurious vibration.

SUMMARY

A vibrator element according to an aspect of the present disclosure includes a vibrating section having a rectangular shape in a plan view and including a first principal surface, a second principal surface in a front-back relation with the first principal surface, and an excitation portion sandwiched by a first excitation electrode provided on the first principal surface and a second excitation electrode provided on the second principal surface and making a thickness-shear vibration, a coupling arm extending from a corner part of the vibrating section in a first direction, and a supporting arm having a side surface at one end part side coupled to the coupling arm and extending in a second direction crossing the first direction, wherein the supporting arm includes a first supporting electrode electrically coupled to the first excitation electrode and bonded to a container via an adhesive member, and a width of the coupling arm along the second direction is four or more times a thickness of the excitation portion along a third direction crossing the first direction and the second direction and equal to or smaller than a length from an end part of the supporting arm at the coupling arm side to the first supporting electrode along the second direction.

A vibrator device according to an aspect of the present disclosure includes a vibrator element, a container housing the vibrator element, and an adhesive member bonding the vibrator element and the container, wherein the vibrator element includes a vibrating section having a rectangular shape in a plan view and including a first principal surface, a second principal surface in a front-back relation with the first principal surface, and an excitation portion sandwiched by a first excitation electrode provided on the first principal surface and a second excitation electrode provided on the second principal surface and making a thickness-shear vibration, a coupling arm extending from a corner part of the vibrating section in a first direction, and a supporting arm having a side surface at one end part side coupled to the coupling arm and extending in a second direction crossing the first direction, the supporting arm includes a first supporting electrode electrically coupled to the first excitation electrode and bonded to the container via the adhesive member, and a width of the coupling arm along the second direction is four or more times a thickness of the excitation portion along a third direction crossing the first direction and the second direction and equal to or smaller than a length from an end part of the supporting arm at the coupling arm side to the first supporting electrode along the second direction.

DESCRIPTION OF EMBODIMENTS

1. First Embodiment

First, a vibrator device1according to a first embodiment will be explained with reference toFIGS.1to3. In the vibrator device1of the embodiment, as a vibrator element20, an AT cut quartz crystal vibrator element is taken as an example for explanation.

InFIG.1, for convenience of explanation of an internal configuration of the vibrator device1, a state without a lid13is shown. The AT cut quartz crystal vibrator element as the vibrator element20has a principal surface on an XZ-plane inclined at about 35 degrees and 15 minutes around an X-axis of X, Y, Z crystal axes from the Z-axis in the Y-axis direction. In the following description, with reference to an axial direction of the AT cut quartz crystal vibrator element, inclined new axes are used as a Y′-axis and a Z′-axis and, in the respective drawings exceptFIG.4, for convenience of explanation, the X-axis, the Y′-axis and the Z′-axis orthogonal to one another are shown. Directions along the X-axis are referred to as “X directions”, directions along the Y′-axis as thickness directions of the vibrator element20are referred to as “Y′ directions”, and directions along the Z′-axis are referred to as “Z′ directions”. An arrow side of each axis is also referred to as “plus side” and an opposite side to the arrow is also referred to as “minus side”. The plus side in the Y′ direction is also referred to as “upper” and the minus side in the Y′ direction is also referred to as “lower”. In the specification, a first direction is the X direction or the plus X direction, a second direction crossing the first direction is the Z′ direction or the minus Z′ direction, and a third direction crossing the first direction and the second direction is the Y′ direction or the plus Y′ direction.

As shown inFIGS.1,2, and3, the vibrator device1of the embodiment includes the vibrator element20, a container10housing the vibrator element20, and an adhesive member50bonding the vibrator element20and the container10.

The vibrator element20includes a vibrating section21having a rectangular shape in a plan view as seen from the Y′ direction, a coupling arm22extending from a corner part as an end part of the vibrating section21in the plus X direction at the side in the plus Z′ direction to the plus X direction as the first direction, and a supporting arm23having a side surface at one end part side coupled to an end part of the coupling arm22in the plus X direction and extending in the minus Z′ direction as the second direction crossing the first direction.

The vibrating section21has the rectangular shape with a long side along the X direction and a short side along the Z′ direction in the plan view. Further, the vibrating section21has a first principal surface21aand a second principal surface21bhaving a front-back relation with the first principal surface21a,and a first excitation electrode31is provided on the first principal surface21aand a second excitation electrode32is provided on the second principal surface21b.A region sandwiched by the first excitation electrode31and the second excitation electrode32is an excitation portion24and a thickness-shear vibration as a main vibration may be excited in the excitation portion24.

The coupling arm22is a region sandwiched by the vibrating section21and the supporting arm23and has a first coupling principal surface22aand a second coupling principal surface22bin a front-back relation with the first coupling principal surface22a.A first lead electrode33electrically coupled to the first excitation electrode31is provided on the first coupling principal surface22a,and a second lead electrode34electrically coupled to the second excitation electrode32is provided on the second coupling principal surface22b.

The supporting arm23has a first supporting principal surface23abonded to the container10via the adhesive member50and a second supporting principal surface23bin a front-back relation with the first supporting principal surface23a,and includes supporting electrodes35at an end part side opposite to the coupling arm22. The supporting electrodes35include a first supporting electrode36and a second supporting electrode37placed apart from the first supporting electrode36. On the first supporting principal surface23a,the first supporting electrode36electrically coupled to the first excitation electrode31and the second supporting electrode37electrically coupled to the second excitation electrode32and located at the side in the minus Z′ direction of the first supporting electrode36are provided.

Note that the first excitation electrode31and the first supporting electrode36are electrically coupled via the first lead electrode33provided on the first coupling principal surface22aof the coupling arm22, and the second excitation electrode32and the second supporting electrode37are electrically coupled via the second lead electrode34provided on the second coupling principal surface22bof the coupling arm22and the second supporting principal surface23bof the supporting arm23. Further, the second supporting electrode37provided on the first supporting principal surface23aand the second lead electrode34provided on the second supporting principal surface23bof the supporting arm23are electrically coupled via a side surface electrode (not shown) provided on a side surface of the supporting arm23.

The adhesive member50is a conductive adhesive agent and includes a first adhesive agent51and a second adhesive agent52placed apart from the first adhesive agent51. Further, the first supporting electrode36is bonded to the container10via the first adhesive agent51and the second supporting electrode37is bonded to the container10via the second adhesive agent52. Note that, specifically, the first supporting electrode36and the second supporting electrode37provided on the supporting arm23are electrically coupled and mechanically joined to internal electrodes14,15provided in the container10via the first adhesive agent51and the second adhesive agent52, respectively. Accordingly, the vibrator element20is bonded into the container10in a cantilevered structure with the supporting arm23as a fixing part.

Next, an influence on vibration characteristics by a width W of the coupling arm22along the Z′ direction as the second direction will be explained with reference toFIGS.4and5. Note thatFIG.4shows a simulation result by a calculation of a spurious Q value for the width W of the coupling arm22with reference to a thickness T of the excitation portion24along the Y′ direction as the third direction. Further,FIG.5shows the vibrator element20with the supporting electrodes35etc. formed thereon.

As shown inFIG.4, for a plate thickness ratio W/T becoming four or more times, for example, when the thickness T of the excitation portion24is 50 μm at a reference frequency 33 MHz, the width W of the coupling arm22is 200 μm and, when the width W of the coupling arm22is 200 μm or more, the spurious Q value tends to be 10,000 or less. Accordingly, the width W of the coupling arm22is set to four or more times the thickness T of the excitation portion24along the Y′ direction, and thereby, the spurious Q value may be 10,000 or less and degradation of the vibration characteristics of the thickness-shear vibration as the main vibration by a spurious vibration may be suppressed.

As shown inFIG.5, the width W of the coupling arm22is set to be equal to or smaller than a length L from an end part of the supporting arm23at the coupling arm22side to the first supporting electrode36along the Z′ direction, and thereby, the distance between the excitation portion24and the adhesive member50may be made longer while the supporting strength is held and an influence on the main vibration by supporting stress such as stress when the adhesive member50is hardened or stress generated by a difference in coefficient of linear expansion between the vibrator element20and a base substrate11may be reduced.

Therefore, the width W of the coupling arm22is set to be four or more times the thickness T of the excitation portion24and equal to or smaller than the length L from the end part of the supporting arm23at the coupling arm22side to the first supporting electrode36, and thereby, the spurious Q value may be 10,000 or less and the vibrator device1with the reduced influence on the vibration by the supporting stress may be obtained.

Note that it is preferable that the width W of the coupling arm22is set to seven or more times the thickness T of the excitation portion24. The width W of the coupling arm22is set to seven or more times the thickness T of the excitation portion24, and thereby, the spurious Q value may be 8,000 or less and the degradation of the vibration characteristics of the main vibration by the spurious vibration may be suppressed.

The container10includes the base substrate11formed by stacking of a first substrate11ahaving a plate shape and a second substrate11bhaving a frame shape and forming a housing space S, the lid13covering the housing space S housing the vibrator element20, and a joint member12joining the base substrate11and the lid13and bringing the housing space S into an air-tight condition.

The two internal electrodes14,15are provided on an upper surface of the first substrate11aof the container10and two external terminals16,17are provided on a lower surface of the first substrate11a.The internal electrode14is electrically coupled to the first supporting electrode36via the first adhesive agent51in an end part opposite to the external terminal16, and the internal electrode15is electrically coupled to the second supporting electrode37via the second adhesive agent52in an end part opposite to the external terminal17. Note that the internal electrode14and the external terminal16are electrically coupled via a through electrode (not shown) penetrating the first substrate11a,and the internal electrode15and the external terminal17are electrically coupled via a through electrode (not shown) penetrating the first substrate11a.

In the embodiment, the AT cut quartz crystal vibrator element is taken as an example of the vibrator element20and explained, however, not limited thereto, the vibrator element may be an SC cut quartz crystal vibrator element.

As described above, in the vibrator device1of the embodiment, the width W of the coupling arm22along the Z′ direction as the second direction is four or more times the thickness T of the excitation portion24along the Y′ direction as the third direction and equal to or smaller than the length L from the end part of the supporting arm23at the coupling arm22side to the first supporting electrode36along the Z′ direction as the second direction. Therefore, the degradation of the vibration characteristics of the main vibration by the spurious vibration may be suppressed and the influence on the vibration by the supporting stress may be reduced.

2. Second Embodiment

A vibrator device1aaccording to a second embodiment will be explained with reference toFIG.6.

InFIG.6, for convenience of explanation of an internal configuration of the vibrator device1a,a state without the lid13is shown.

The vibrator device1aof the embodiment is the same as the vibrator device1of the first embodiment except that a short side direction of a vibrating section21cis a first direction and a long side direction of the vibrating section21cis a second direction. The explanation will be made with a focus on differences from the above described first embodiment and the description of the same items will be omitted.

As shown inFIG.6, in the vibrator device1aof the embodiment, the vibrating section21cof a vibrator element20ahas a rectangular shape in a plan view as seen from the Y′ direction, the X direction as the first direction is the short side direction, and the Z′ direction as the second direction is the long side direction. Further, the coupling arm22extends from a corner part as an end part of the vibrating section21cin the minus X direction at the side in the plus Z′ direction to the plus Z′ direction, and the supporting arm23extends from an end part of the coupling portion22in the plus Z′ direction to the plus X direction.

According to the configuration, in the vibrator element20ahaving the vibrating section21cwith the long side along the Z′ direction, the same effects as the effects obtained in the first embodiment may be obtained.

A vibrator device1baccording to a third embodiment will be explained with reference toFIG.7.

InFIG.7, for convenience of explanation of an internal configuration of the vibrator device1b,a state without the lid13is shown.

The vibrator device1bof the embodiment is the same as the vibrator device1of the first embodiment except that only one adhesive member50bis provided, a second supporting electrode37bis placed on the second supporting principal surface23b,the second supporting electrode37bis electrically coupled to a container10bvia a bonding wire55, and a position of an internal electrode14band a shape of an internal electrode15bare different. The explanation will be made with a focus on differences from the above described first embodiment and the description of the same items will be omitted.

As shown inFIG.7, in the vibrator device1bof the embodiment, the second supporting electrode37bis placed on the second supporting principal surface23band the second supporting electrode37bis electrically coupled to the internal electrode15bof the container10bvia the bonding wire55.

The supporting arm23is joined to the container10bat the first supporting principal surface23aside via the adhesive member50bas a conductive adhesive agent. More specifically, a first supporting electrode36bprovided on the first supporting principal surface23ais electrically coupled to the internal electrode14bprovided in the container10bvia the adhesive member50b.Therefore, the distance from the vibrating section21to the adhesive member50bmay be sufficiently separated, and thereby, the influence by spurious may be reduced and the influence by the supporting stress may be further suppressed.

According to the configuration, the same effects as the effects obtained in the first embodiment may be obtained. Note that, in the embodiment, the supporting arm23is bonded to the container10bby the one adhesive member50b,however, in order to increase the supporting strength, the supporting arm23may be bonded to the container10bby two adhesive members50blike the first embodiment.