JP5732903B2 - Vibration element, vibrator, oscillator, gyro sensor and electronic equipment - Google Patents

Description

  The present invention relates to a piezoelectric vibration element, a vibration gyro element, and the like, and in particular, a piezoelectric vibration element, a piezoelectric vibrator, a piezoelectric oscillator, a vibration gyro element, a vibration gyro sensor, and an electronic device using the same that are miniaturized and have improved frequency temperature characteristics. Regarding equipment.

Conventionally, piezoelectric devices have been widely used as reference frequency sources in small information devices such as mobile computers and hard disk drives, and mobile communication devices such as mobile phones. As electronic devices equipped with a piezoelectric device are further downsized, the piezoelectric device is required to be further downsized.
Patent Document 1 discloses a tuning fork type crystal resonator cut out in the range of 0 ° to −15 ° around an electric axis of crystal (one of crystal axes). Quartz vibration with improved frequency temperature characteristics of the flexural vibration mode of the main vibration by bringing the resonance frequencies f _F and f _T of the flexural vibration mode and the torsional vibration mode excited by the tuning fork crystal resonator close to each other and coupling them. A child.
In general, the frequency-temperature characteristic Δf / f of a crystal resonator is expressed by a polynomial relating to the temperature T, but is practically approximated by a cubic equation, and the first to third coefficients are represented by α, β, and γ.
The frequency temperature characteristic Tf _F in the flexural vibration mode is affected by the torsional vibration mode and depends on the piezoelectric substrate h. For various cutting angles θ, the thickness h is set so that the primary coefficient α = 0, and further, the cutting angle θ and the thickness h at which the secondary coefficient β becomes zero are set from values obtained by calculation in advance. To do. Thus, it is disclosed that the frequency temperature characteristic Tf _F depends only on the third-order coefficient γ, and a crystal resonator having a good temperature characteristic can be obtained.

Further, Patent Document 2 discloses a tuning fork type piezoelectric vibrator in which an enlarged portion wider than the vibrating arm is provided at each tip portion of a plurality of vibrating arms parallel to each other. The enlarged portion has a bottomed hole, and it is noted that the bottomed hole is filled with a material having a specific gravity greater than that of the piezoelectric material to form a weight, thereby reducing the size of the tuning fork type piezoelectric vibrator. ing.
Patent Document 3 discloses a vibrating gyro element. The vibration gyro element includes a base, a pair of detection vibrating arms linearly extending from the base to both sides, and a pair of connecting arms extending from the base to both sides in a direction perpendicular to the detection vibrating arms. And a pair of drive vibration arms each extending from the front end of each connecting arm to both sides perpendicularly to the connecting arm. In addition, two pairs of beams extending from the base along each detection arm and a pair of support portions connected to each beam extending in the same direction are provided on the same plane, and the support portions are detected. The vibration arm for use is extended in the direction outside the detection vibration arm and between the drive vibration arms.

JP-A-55-75326 JP 2004-282230 A JP 2010-2430 A

However, the tuning-fork type piezoelectric vibrator described in Patent Document 1 in which the frequency temperature characteristics are improved by bringing the frequencies of the bending vibration mode and the torsional vibration mode close to each other and coupling them to each other is difficult to downsize. there were.
Further, the tuning fork type piezoelectric vibrator described in Patent Document 2 can be miniaturized by forming a weight portion at the tip of the vibrating arm, but the frequency temperature characteristic is a secondary characteristic, and the frequency stability is improved. There was a problem.
Further, the vibrating gyro element described in Patent Document 3 has a problem that the sensitivity of the angular velocity changes due to a temperature change.
The present invention has been made in order to solve the above problems, and includes a piezoelectric vibration element, a piezoelectric vibrator, a piezoelectric oscillator, a vibration gyro sensor, and an electronic device using these, which are reduced in size and improved in frequency temperature characteristics. It is to provide.

SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.
A vibration element according to an aspect of the present invention includes a base portion, the base portion extending in the first direction, arranged in a second direction orthogonal to the first direction, and coupled with bending vibration and torsional vibration. A pair of vibrating arms that vibrate, wherein the vibrating arm includes a weight portion and an arm portion disposed on the base side of the weight portion in plan view, and the weight portions are A first groove portion extending from the outer edge on the opposite side to the arm portion side to the intermediate portion is provided on at least one of the front surface and the back surface in a front-back relationship, and the arm portions are A second groove portion is provided along the first direction on at least one of the front surface and the back surface, and the side surface connecting the front surface and the back surface of the arm portion; and the second groove portion An electrode is provided on the inner surface of the substrate.
A vibration element according to an aspect of the present invention includes a base portion, the base portion extending in the first direction, arranged in a second direction orthogonal to the first direction, and coupled with bending vibration and torsional vibration. A pair of vibrating arms that vibrate, wherein the vibrating arm includes a weight portion and an arm portion disposed on the base side of the weight portion in plan view, and the weight portions are A first groove is provided on at least one of the front and back surfaces in a front-back relationship, and the arm portion is formed along the first direction on at least one of the front and back surfaces in a front-back relationship. The first groove portion is connected to the second groove portion and extends to an outer edge of the weight portion on the opposite side to the arm portion side. An electrode is provided on a side surface connecting the front surface and the back surface of the second groove portion and an inner surface of the second groove portion. And wherein the Rukoto.
The vibration element according to an aspect of the present invention is characterized in that, in the vibration element, at least a part of the first groove portion is wider in the second direction than the second groove portion.
The vibration element according to an aspect of the present invention is characterized in that, in the vibration element, the weight portion is wider in the second direction than the arm portion.
The vibration element according to an aspect of the present invention is the vibration element described above, wherein the vibration element is formed of a quartz plate, and an angle formed between a normal line of a main surface of the quartz plate and an optical axis of the quartz crystal is from 0 degrees. It is in the range of −15 degrees.
The vibrating element according to an aspect of the present invention is the above vibrating element, wherein the base is a base body from which the vibrating arm extends, and an end of the base body opposite to the vibrating arm in plan view. A connecting portion that is narrower than a width along the second direction of the base body, and a support arm that extends from an end of the connecting portion opposite to the base portion in a plan view. It is characterized by having.
A vibrator according to an aspect of the present invention includes the above vibration element and a substrate on which the vibration element is placed.
An oscillator according to an aspect of the present invention includes the above vibration element and an IC that drives the vibration element.
The gyro sensor which concerns on a certain form of invention is equipped with the said vibration element, It is characterized by the above-mentioned.
An electronic apparatus according to an aspect of the invention includes the above-described vibration element.

  Application Example 1 A piezoelectric vibrating element according to the present invention includes a plurality of vibrating arms, a base portion that connects one end of each vibrating arm, and the other end portion of each vibrating arm that is connected to each other. A weight portion wider than the width of the other end portion of the arm, a first groove portion extending along a longitudinal direction of each vibration arm on at least one of the front and back surfaces of the weight portion, and each vibration A piezoelectric substrate provided with second grooves formed on the front and back surfaces of the arms, and on the front and back surfaces of the vibrating arms including both the front and back surfaces of the weight portion and the second groove portions; A piezoelectric vibration element that performs bending-torsion coupled vibration, and includes excitation electrodes that are respectively formed and electrically connected to a plurality of electrode pads provided on the base portion, The frequency temperature characteristic of the vibration element is a cubic characteristic with respect to temperature.

  A weight portion is formed at the tip of each vibration arm of the tuning fork type piezoelectric vibration element, and first grooves extending linearly along the longitudinal direction of the vibration arm are formed on the front and back surfaces of the weight portion. Second grooves are respectively formed on the front and back surfaces along the vibration center line of the arm. With this configuration, the bending vibration and the torsional vibration excited by the tuning fork type piezoelectric vibration element can be brought close to each other and coupled. The frequency temperature characteristic of the flexural vibration of the flexural-torsional coupled vibration becomes a third-order characteristic with respect to temperature, and there is an effect that an excellent temperature characteristic and a miniaturized piezoelectric vibration element are obtained.

  Application Example 2 In the piezoelectric vibration element, the base has a base body having one end connected to the one end of the vibrating arm, and a side facing the one end of the base main body connected to the vibrating arm. The piezoelectric vibration element according to Application Example 1, further comprising: a connecting portion connected to the other end; and a support arm connected via the connecting portion and extending away from the base body. is there.

  The base portion of the piezoelectric vibration element has a base body, a connecting portion, and L-shaped and inverted L-shaped support arms, and connects the L-shaped and inverted L-shaped end portions. The connecting portion is connected to the center of one end of the base body through a connecting portion. For this reason, the vibration energy leaking from the vibrating arm to each support arm can be reduced, the CI value is reduced, and the impact resistance is improved. As a result, there is an effect that a piezoelectric vibration element having no risk of frequency fluctuation due to deficiency or breakage due to impact can be obtained.

  Application Example 3 In the piezoelectric vibration element, the piezoelectric substrate is formed of a crystal plate, and the normal line of the main surface of the crystal plate is 0 degree around the electric axis of the crystal crystal with respect to the optical axis of the crystal crystal. The piezoelectric vibration element according to Application Example 1 or 2, wherein the piezoelectric vibration element is tilted at an angle within a range of -15 degrees to -15 degrees.

  A tuning fork type piezoelectric vibration element is configured in which the cutting angle of the piezoelectric substrate is rotated in the range of 0 ° to −15 ° around the electric axis (X axis). By selecting such a cutting angle, it becomes possible to make the first and second coefficients of the polynomial representing the frequency temperature characteristic of the flexural-torsion coupled vibration almost zero, and a piezoelectric vibration element having excellent temperature characteristics can be obtained. There is an effect that it is.

  Application Example 4 In the piezoelectric vibration element, any one of Application Examples 1 to 3, wherein the first groove portion includes a plurality of grooves that are separated from each other along the longitudinal direction. It is a piezoelectric vibration element as described in above.

  By configuring the piezoelectric vibration element in which the first groove portion is formed as described above, the frequency temperature characteristic of the bending vibration of the bending-torsion coupled vibration becomes a third-order characteristic with respect to temperature, and the piezoelectric vibration having excellent temperature characteristics. There is also an advantage that an element can be obtained and that a lead electrode that electrically connects the excitation electrodes can be formed on the flat surface of the weight portion.

  Application Example 5 In the piezoelectric vibration element, the first groove portion extends from a tip edge of the weight portion to an intermediate portion of the weight portion and is symmetrical with respect to the vibration center line of the vibration arm. It is a piezoelectric vibration element as described in any one of the application examples 1 thru | or 3 currently formed in the position of the front and back of the said weight part.

  By configuring the piezoelectric vibration element in which the first groove portion is formed as described above, the frequency temperature characteristic of the main vibration of the bending-torsion coupled vibration becomes a third-order characteristic with respect to temperature, and the temperature characteristic is improved. There is also an advantage that a lead electrode for electrically connecting the excitation electrodes can be formed on the flat surface of the weight portion.

  Application Example 6 In the piezoelectric vibration element, the first groove portion is formed continuously with the second groove portion, and the tip portion of the first groove portion extends to the tip edge of the weight portion. The piezoelectric vibration element according to any one of Application Examples 1 to 3, wherein the piezoelectric vibration element is formed at positions of front and back surfaces of the weight portion that are line-symmetric with respect to the vibration center line.

  By configuring the piezoelectric vibration element in which the first groove portion is formed as described above, the frequency temperature characteristic of the bending vibration of the bending-torsion coupled vibration becomes a third-order characteristic with respect to the temperature, and the temperature characteristic of the piezoelectric vibration element is improved. There is also an advantage that the first and second groove forming masks become easy.

  Application Example 7 In the piezoelectric vibration element according to Application Example 5, wherein the first groove portion is formed such that at least a part of the width is wider than the second groove portion. It is a vibration element.

  By configuring the piezoelectric vibration element in which the first groove portion is formed as described above, the frequency temperature characteristic of the bending vibration of the bending-torsion coupled vibration becomes a third-order characteristic with respect to the temperature, and the temperature characteristic of the piezoelectric vibration element is improved. There is also an advantage that the bending vibration frequency and the torsional vibration frequency can be easily coupled by appropriately setting the width of the first groove portion.

  Application Example 8 A piezoelectric vibrator according to the present invention includes the piezoelectric vibration element according to any one of Application Examples 1 to 6 and an insulating substrate on which the piezoelectric vibration element is mounted. This is a piezoelectric vibrator.

  A bending vibrator and a torsional vibration excited by a tuning fork type piezoelectric vibration element are brought close to each other, and a tuning fork type piezoelectric vibration element excited by a bending-torsion coupled vibration is accommodated in an insulating substrate to constitute a piezoelectric vibrator. Thus, there is an effect that a piezoelectric vibrator having a small size, a high Q value, and excellent frequency temperature characteristics can be obtained.

  Application Example 9 A piezoelectric oscillator according to the present invention includes a piezoelectric vibration element according to any one of Application Examples 1 to 6, an IC component that excites the piezoelectric vibration element, and the piezoelectric vibration element that is hermetically sealed. And a package for accommodating the IC component.

  By constructing a piezoelectric oscillator including a tuning fork type piezoelectric vibration element in which bending vibration and torsional vibration are brought close to each other, and bending-torsional coupled vibration is excited, an IC component, and a package for accommodating these components, There is an effect that a piezoelectric oscillator having a small size and excellent frequency temperature characteristics can be obtained.

  Application Example 10 A vibration gyro element according to the present invention is characterized in that the piezoelectric vibration element according to Application Example 1 includes a detection vibrating arm for detecting an angular velocity connected from the base. It is.

  A weight portion is formed at the tip of each vibration arm for each drive arm, and a first groove portion extending linearly along the longitudinal direction of the vibration arm is formed on the front and back surfaces of the weight portion. A vibrating gyro element is formed by forming second grooves on the front and back surfaces along the vibration center line of the arm. When such a vibration gyro element is configured, the frequency temperature characteristic of the bending vibration, which is the main vibration of the bending-torsion coupled vibration excited by the vibration arm for each driving arm, becomes a third-order characteristic with respect to the temperature, and the excellent temperature There is an effect that a small vibration gyro element having characteristics can be obtained.

  Application Example 11 A vibration gyro sensor is a vibration gyro sensor including the vibration gyro element according to Application Example 10 and a package that accommodates the vibration gyro element.

  When the vibration gyro sensor is configured as described above, the frequency temperature characteristic of the main vibration of the bending-torsion coupled vibration excited by the vibration arm for each drive arm is improved, and the size is reduced by providing the weight portion. The effect is that a vibration gyro sensor can be obtained.

  Application Example 12 An electronic device according to the present invention is an electronic device including the piezoelectric vibrator described in Application Example 8 or the vibration gyro sensor described in Application Example 11.

  As described above, by configuring the electronic device including the piezoelectric vibrator, there is an effect that the stability of the frequency source of the electronic device is improved. In addition, by configuring an electronic device including the above vibration gyro sensor, there is an effect that the change in sensitivity of the angular velocity due to temperature can be reduced.

(A) is the schematic plan view which showed the structure of the piezoelectric vibration element which concerns on this invention, (b) is sectional drawing of a vibrating arm. Sectional drawing of the weight part provided in the front-end | tip part of a vibrating arm. (A)-(c) is a top view which shows the modification of a weight part, respectively. (A) is explanatory drawing which shows the frequency change of each of bending vibration and torsional vibration when a groove is formed at the tip of the beam, and (b) is each of bending vibration and torsional vibration when a groove is formed at the center of the beam. Explanatory drawing which shows the frequency change of (c), (c) is explanatory drawing which shows the frequency change of each of bending vibration and torsional vibration at the time of changing the plate | board thickness of a beam. (A) (b) is a top view at the time of providing a recessed part in the front and back of a weight part, (c) is a top view at the time of providing a groove in the front and back of the front-end | tip part of a weight part. FIGS. 5A to 5C are diagrams showing the corresponding resonance frequency and resonance frequency difference (Δf) of bending vibration and torsional vibration, respectively. (A) is a frequency temperature characteristic of tuning fork vibration (bending vibration), (b) is a frequency temperature characteristic of torsional vibration, and (c) is a diagram showing frequency temperature characteristics of bending-torsion coupled vibration. The figure which shows the coupling | bonding of the bending vibration and torsional vibration at the time of changing the board thickness h of a vibrating arm. (A) is a diagram showing the relationship between the plate thickness h and the respective primary and secondary coefficients of flexural-torsional vibration, and (b) is an enlarged view of the main part thereof. Sectional drawing of the piezoelectric vibrator using bending-torsion coupling vibration. Sectional drawing of a piezoelectric oscillator. (A) is a top view of a vibration gyro sensor, (b) is sectional drawing, (c) is a schematic diagram explaining operation | movement. FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic plan view showing a configuration of a piezoelectric vibration element 1 according to an embodiment of the present invention. The piezoelectric vibration element 1 includes a flat plate-like piezoelectric substrate 7 and thin film electrodes 25 formed on the front and back surfaces and side surfaces of the piezoelectric substrate 7.
As shown in FIG. 1A, the piezoelectric substrate 7 includes a plurality of (in this example, two) vibrating arms 15a and 15b that are linear (parallel to each other) and extend linearly, and each vibrating arm 15a. , 15b are connected integrally to the base 10 that connects between one end (base end) and the other ends (tips) of the vibrating arms 15a and 15b, respectively, and each vibrating arm 15a, Weight portions 20a, 20b wider than the width of the other end of 15b, and second grooves 17a (17b) formed on the front and back surfaces along the vibration center line C of each of the vibrating arms 15a, 15b, respectively. , 18a (18b).
The weight portions 20a and 20b are provided on at least one surface (both surfaces in this example) along the vibration center line C in the longitudinal direction of one of the vibrating arms 15a and 15b (one end of the vibrating arm and the other). First groove portions 22a (22b) and 24a (24b) extending linearly along an extending direction along a line connecting the end portions are provided. 2 and FIG. 3, 22b and 24b have shown the 1st groove part formed in the back surface of the weight parts 20a and 20b, respectively.
The vibration center line C is a line extending in the longitudinal direction of the vibrating arm passing through the center of gravity of the vibrating arm.

  The thin film electrode 25 shown in FIG. 1B includes front and back surfaces of the weight portions 20a and 20b and the first groove portions 22a, 22b, 24a, and 24b, as shown in FIG. A plurality of electrode pads (not shown) formed on the front and back surfaces and side surfaces of the vibrating arms 15a and 15b including the inside of the two groove portions 17a (17b) and 18a (18b), respectively, and provided on the base portion 10; Excitation electrodes 30, 32, 34, and 36 that are electrically connected to each other by lead electrodes (not shown). The thin film electrode 25 is formed in a vacuum apparatus using a vapor deposition method or a sputtering method. In the case where the function as the weight parts 20a and 20b can be achieved only by attaching a metal having a high density in the first groove parts 22a, 22b, 24a and 24b, such as gold Au, the weight parts 20a and 20b are not necessarily provided. There is no need to form electrodes on a flat surface.

A base 10 shown in FIG. 1A includes a base main body 12a and a middle portion of the other end edge (vibrating arm) opposite to the vibrating arms 15a and 15b of the base main body 12a in order to reduce vibration leakage and improve impact resistance. A narrow connecting portion 12d provided at one end connected to the other end and the other end connected to the base portion 12d and extending from the tip of the base portion 12a along the width direction. And a pair of left and right support arms 12b and 12c extending in the longitudinal direction with the vibrating arms 15a and 15b interposed therebetween. That is, the base end portion of the L-shaped support arm 12b and the base end portion of the inverted L-shaped support arm 12c are connected, and this connection portion is one end edge of the base main body 12a via the connecting portion 12d. This is an example of a base portion that is connected to the center and has a U-shape, and the base ends of the vibrating arms 15a and 15b are connected to the other end edge of the base portion main body 12a.
In the embodiment of FIG. 1, the base 10 has been described as including the base main body 12a, the connecting portion 12d, and the pair of left and right support arms 12b and 12c, but only the base main body 12a may be used.
The vibrating arms 15a and 15b extend in parallel with each other at an interval from the end of the base body 12a, and the other ends of the vibrating arms 15a and 15b are provided at the distal ends of the vibrating arms 15a and 15b, respectively. The weight portions 20a and 20b which are wider than the width are integrated and integrated.

  For example, when a piezoelectric substrate is used as the piezoelectric substrate 7, a Z plate (a substrate cut out perpendicular to the optical axis (Z axis)) is rotated from 0 ° to −15 ° around the electric axis (X axis). A cut out substrate is used. Note that the outer shape of the piezoelectric substrate 7, the first groove portions 22a, 22b, 24a, 24b of the weight portions 20a, 20b and the second groove portions 17a (17b), 18a (18b) of the vibrating arms 15a, 15b are formed by photolithography. It is formed by etching using technology.

FIG. 1B is a cross-sectional view taken along the line P-P in FIG. 1A and shows the arrangement of the excitation electrodes 30, 32, 34, and 36 formed on the vibrating arms 15a and 15b, respectively. The excitation electrodes 30 and 34 are formed on the surface and side surfaces of the grooves 17a (17b) and 18a (18b), and the excitation electrodes 32 and 36 are formed on both side surfaces of the vibration arms 15a and 15b, respectively.
The excitation electrodes 30 and 36 and the excitation electrodes 32 and 34 are applied with voltages having different signs from each other via the electrode pads. That is, when a positive voltage is applied to the excitation electrodes 30 and 36, a negative voltage is applied to the excitation electrodes 32 and 34, and an electric field as shown by an arrow in FIG. A tuning fork vibration (bending vibration) that is symmetrical with respect to the center line Cg passing through is excited.
In addition, by forming the groove portions 17a (17b) and 18a (18b), the electric field strength is increased, and tuning fork vibration can be excited more efficiently. That is, the CI (crystal impedance) of the piezoelectric vibration element can be reduced.

FIG. 2 is a QQ cross-sectional view of FIG. As shown in the plan view of FIG. 1A and the cross-sectional view of FIG. 2, the weight portions 20a and 20b have a rectangular flat plate shape, and the first groove portions 22a, 22b, 24a, and 24b correspond to the vibrating arms 15a. , 15b are spaced apart from both ends of the weights 20a, 20b along the longitudinal direction, are symmetrical with respect to the vibration center line C, and have a first groove on the distal end side and a first groove on the proximal end side. 1 groove portion is provided.
3A to 3C are plan views showing modifications of the first groove portions 22a, 22b, 24a, and 24b. As shown in FIG. 1A, the weight portions 20a and 20b have the same shape, and therefore, description will be made using one weight portion 20a. The first groove portion 22a (22b) shown in FIG. 3A extends from the longitudinal tip edge of the vibrating arm 15a of the weight portion 20a to the middle portion in the longitudinal direction and is symmetrical with respect to the vibration center line C. Has been.

The first groove portion 22a (22b) shown in FIG. 3B has a first end portion of the first groove portion 22a (22b) continuously formed with a distal end portion of the second groove portion 17a (17b), The tip portion of the groove portion 22a (22b) extends to the tip edge of the weight portion 20a and is symmetrical with respect to the vibration center line C.
As for the 1st groove part 22a (22b) shown in FIG.3 (c), the width | variety of the at least one part is formed wider than the width | variety of the 2nd groove part 17a (17b).

The tuning fork type crystal resonator element 1 is excited by bending vibration that passes through the center of gravity and vibrates symmetrically with respect to the center line Cg in the direction of the vibrating arms 15a and 15b, and torsional vibration that is symmetrical with respect to the center line Cg. Is done. By appropriately forming the excitation electrodes, it is possible to select which vibration mode is the main vibration. FIG. 1 shows an embodiment in which tuning fork vibration (bending vibration) is set as a main vibration mode.
As an example of the piezoelectric vibration element of the present invention, a tuning fork type crystal vibration element 1 is formed by using a substrate cut out by rotating a quartz crystal Z plate around an electric axis (X axis) by θ (range of 0 ° to −15 °). Form. Second vibrating portions 17a, 17b, 18a, and 18b are formed in the vibrating arms 15a and 15b, and the first groove portions are formed on the front and back surfaces of the weight portions 20a and 20b provided at the distal ends of the vibrating arms 15a and 15b. 22a, 22b, 24a and 24b are formed.
That is, the tuning fork type crystal resonator element 1 is excited by appropriately selecting the cutting angle θ, the first groove portions 22a, 22b, 24a, 24b, and the second groove portions 17a, 17b, 18a, 18b. The two vibration modes are coupled by bringing the resonance frequencies f _F and f _T of the bending vibration (tuning fork vibration) and the torsion vibration close to each other, thereby improving the frequency temperature characteristic of the bending vibration of the main vibration and reducing the size. A tuning fork-type crystal resonator element is formed.

Means for bringing the resonance frequencies f _F and f _T of the bending vibration and the torsional vibration close to each other will be described with reference to FIGS.
4A to 4C show the resonance frequency f _{F of} flexural vibration excited by the piezoelectric vibration element (tuning fork type piezoelectric vibration element) shown in FIG. 1A and the resonance frequency f _{T of} torsional vibration. Depending on the thickness h of the first groove portions 22a (22b) and 24a (24b) of the weight portions 20a and 20b, the second groove portions 17a and 17b of the vibrating arms 15a and 15b, and the vibrating arms 15a and 15b. It is a figure explaining qualitatively how it changes. 4A and 4B, the horizontal axes A and B indicate the shape of the beam (vibrating arm) 15. A is a case where a groove is formed in the beam 15, and B is a case where a groove is formed. . FIG. 4C shows a case where the plate thickness of the beam 15 is changed.

The resonance frequencies of the bending vibration and the torsional vibration excited by the beam 15 before forming the groove are f _F and f _T, and the resonance frequencies when the groove 22a (22b) is formed at the tip of the beam 15 are respectively shown. Let f ′ _F and f ′ _T. As shown in FIG. 4A, when the groove 22a (22b) is formed at the tip of the beam (vibrating arm) 15, the resonance frequencies f ′ _T and f ′ _F of the bending vibration and the torsional vibration are both The frequency increase width df _F = (f ′ _F −f _F ) of the bending vibration is larger than the frequency increase width df _T = (f ′ _T −f _T ) of the torsional vibration.

On the other hand, as shown in FIG. 4B, when the groove portion 17a (17b) is formed in the central portion of the beam (vibrating arm) 15, the resonance frequencies f ′ _T and f ′ _F of torsional vibration and bending vibration are both obtained. Although it decreases, the frequency reduction width df _T = (f _T −f ′ _T ) of the torsional vibration becomes larger than the frequency reduction width df _F = (f _F −f ′ _F ) of the bending vibration.
Further, as shown in FIG. 4C, when the plate thickness h of the beam 15 is increased, the bending vibration frequency f ′ _F slightly decreases from the original frequency f _F, but the torsional vibration resonance frequency f. _'T is increased than the original frequency _{f T.}
As described above, by appropriately selecting the position of the groove formed on the beam (vibrating arm) 15 and the thickness of the beam (vibrating arm) 15, the respective resonant frequencies of bending vibration and torsional vibration are made close to each other. Is possible.

  FIGS. 5A to 5C show the weight portion 20a when only the concave portions and the groove portions formed on the front and back surfaces of the weight portions 20a and 20b are changed without changing the outer shape of the tuning-fork type crystal vibrating element 1. It is a top view of 20b. 5 (a) and 5 (b) show concave portions 21a (axisymmetrically opposed to the vibration center line C along the longitudinal direction of the vibrating arms 15a and 15b in the central portions of the front and back surfaces of the weight portions 20a and 20b. 21b) and 21′a (21′b) are formed. The area of the recesses 21a (21b) and 21′a (21′b) in FIG. 5B is larger than the area of the recesses 21a (21b) and 21′a (21′b) in FIG. It is formed. FIG. 5C shows groove portions 22a (22b), 24a that are placed symmetrically with respect to the vibration center line C along the longitudinal direction of the vibrating arms 15a, 15b from the front and back surfaces of the weight portions 20a, 20b. This is an example in which (24b) is formed.

FIG. 6 shows the resonance frequencies f _F and f of the bending vibration and the torsional vibration excited in the tuning-fork type crystal vibrating element 1 having the weight portions 20a and 20 having the shapes shown in FIGS. and _T, the difference frequency _{Δf = (f T -f F)} , which is a diagram obtained by the simulation using the finite element method the. The left side of the vertical axis shows the resonance frequencies f _F and f _T, and the right side of the vertical axis shows the difference frequency Δf. The horizontal axis is indicated by reference symbols a, b, and c corresponding to the tuning-fork type crystal vibrating element 1 having the weight portions 20a and 20 having the shapes shown in FIGS.
Comparing the respective resonance frequencies of a and b in FIG. 6, when the size of the concave portions of the weight portions 20 a and 20 b is changed without changing the outer shape of the tuning fork type crystal vibrating element 1, the area of the concave portion It can be seen that the difference frequency Δf is smaller as the difference is larger. As shown in FIG. 4A, when the mass of the tip of the beam (vibrating arm) 15 is reduced, the increase in the frequency of bending vibration is larger than the increase in the frequency of torsional vibration, and the difference frequency Δf = ( This can also be explained by the fact that f _T −f _F ) decreases. It can also be explained from FIG. 4A that the frequency of the bending vibration of b is higher than the frequency of bending vibration of a.
FIG. 6c shows an example in which the groove portions 22a (22b) and 24a (24b) are formed at the tip portions of the weight portions 20a and 20b, and shows that the difference frequency Δf = (f _T −f _F ) can be further reduced. . By reducing the difference frequency Δf = (f _T −f _F ), for example, when the value of Δf / ((f _T −f _F ) / 2) is 10% or less, the coupling between the bending vibration and the torsional vibration is reduced. It becomes dense and the frequency temperature characteristic of the bending vibration as the main vibration is improved.

FIG. 7 is a qualitative view showing how the frequency temperature characteristic of the main vibration is improved by coupling the bending vibration and the torsional vibration excited by the tuning-fork type crystal resonator element 1 with each other. It is a representation. In general, the frequency-temperature characteristic Δf / f (= (f−f ₀ ) / f, f ₀ is a frequency at a predetermined temperature) of a crystal resonator can be expressed by a polynomial of temperature T as shown in Equation (1). it can.
Δf / f = α (T−T ₀ ) + β (T−T ₀ ) ² + γ (T−T ₀ ) ³ + (1)
FIG. 7A is a frequency temperature characteristic of flexural vibration, which is the main vibration, and exhibits a quadratic curve with respect to temperature T. FIG. FIG. 7B shows the frequency-temperature characteristics of torsional vibration, and the frequency Δf / f is approximated with respect to the temperature T by a linear expression. FIG. 7C is a diagram showing the frequency temperature characteristics of the bending vibration, which is the main vibration when bending vibration and torsional vibration are combined. By coupling the torsional vibration to the bending vibration of the main vibration, it becomes possible to make the primary coefficient α and the secondary coefficient β of the polynomial Δf / f representing the frequency temperature characteristic of the bending vibration substantially zero, and the bending of the main vibration The frequency-temperature characteristic of vibration can be approximated by a third-order coefficient γ and exhibits a cubic curve (third-order characteristic) in a desired temperature range including room temperature as shown in FIG.

FIG. 8 shows the degree of coupling between flexural vibration and torsional vibration obtained by simulation when the plate thickness h of the vibrating arms 15a and 15b of the tuning fork crystal resonator 1 is changed. The resonance frequency f _F of the bending vibration is almost flat with respect to the thickness h, and decreases slightly as h increases. Meanwhile, the resonance frequency f _T of the torsional vibration, depending on the increase in the thickness h, increases so as to be substantially proportional. In the example of FIG. 8, it can be seen that the coupling increases with a plate thickness h slightly less than 86 μm.

FIG. 9A shows, by simulation, the primary coefficient α, the secondary coefficient β, the primary coefficient α ′, and the secondary coefficient β ′ of the torsional vibration excited by the tuning fork type crystal resonator 1. This is illustrated. The primary coefficient α and the secondary coefficient β of the bending vibration are indicated by diamonds ◆ and squares ■, respectively, and the primary coefficient α ′ and the secondary coefficient β ′ of the torsional vibration are indicated by white diamonds ◇ and white squares □, respectively. It can be seen from FIG. 9A that the primary coefficient α ′ of the torsional vibration is larger than the other coefficients. That is, the primary coefficient α ′ is dominant in torsional vibration.
Further, it can be seen that the primary coefficient α and the secondary coefficient β of the bending vibration are extremely small in the example of FIG. 9 when the plate thickness h of the vibrating arms 15a and 15b is in the range of 84 μm to 85 μm.

FIG. 9B shows the first and second coefficients α, β, α ′, β of the bending vibration and the torsional vibration when the plate thickness h of the vibrating arms 15a, 15b is changed in the range of 82 μm to 86 μm. It is the figure which showed 'with respect to plate thickness h. In the example of FIG. 9B, it has been found that both the primary coefficient α and the secondary coefficient β of the bending vibration become substantially zero in the vicinity of the plate thickness h = 84.5 μm. It can also be seen that the secondary coefficient β ′ of the torsional vibration is almost zero in the vicinity of the plate thickness h = 84.5 μm.
In other words, in the example of the tuning fork type crystal resonator element 1 of FIG. 9, by setting the plate thickness h to 84.5 μm, both the primary coefficient α and the secondary coefficient β of the frequency temperature characteristic of the bending vibration that is the main vibration are zero. It can be. Therefore, the frequency temperature characteristic of the bending vibration exhibits a cubic curve, and the frequency temperature characteristic is greatly improved, and the vibrating arms are shortened by providing the weight portions 20a and 20b, so that a small tuning fork type crystal vibrating element 1 is obtained. It is done.

Further, by irradiating the electrodes formed on the front and back surfaces of the weight portions 20a and 20b, the electrodes formed in the first groove portions 22a, 22b, 24a and 24b, and the electrodes formed on the vibrating arms 15a and 15b with laser light, It is possible to finely adjust the degree of coupling between the bending vibration and the torsional vibration excited by the tuning fork type piezoelectric vibrator.
In consideration of frequency fluctuation due to drop impact or the like, it may be better to avoid the electrodes on the front and back surfaces of the weight portion (particularly the tip portion) and to form the weight electrode only in the first groove portion.

  As shown in FIG. 1, a piezoelectric vibrating element (tuning fork type piezoelectric vibrating element) 1 according to the present invention has a weight portion formed at the tip of each vibrating arm, and is arranged on the front and back surfaces of the weight portion in the longitudinal direction of the vibrating arm. A first groove extending linearly along the first groove is formed, and a second groove is formed on the front and rear surfaces along the vibration center line of each vibrating arm. With this configuration, the bending vibration and the torsional vibration excited by the tuning fork type piezoelectric vibration element 1 can be brought close to each other and coupled. The frequency temperature characteristic of the flexural vibration, which is the main vibration of the flexural-torsional coupled vibration, becomes a third-order characteristic with respect to temperature, and there is an effect that a piezoelectric vibration element having excellent temperature characteristics and a reduced size can be obtained.

  Further, as shown in FIG. 1A, the base of the piezoelectric vibration element (tuning fork type piezoelectric vibration element) 1 includes a base body, a connecting portion, and L-shaped and inverted L-shaped support arms. The L-shaped and the inverted L-shaped end portions are connected to each other, and the connecting portion is connected to the center of one end portion of the base body through a connecting portion. For this reason, the vibration energy leaking from the vibrating arm to each support arm can be reduced, the CI value is reduced, and the impact resistance is improved. As a result, there is an effect that a piezoelectric vibration element having no risk of frequency fluctuation due to deficiency or breakage due to impact can be obtained.

Further, the piezoelectric vibration element (tuning fork type piezoelectric vibration element) 1 in which the cutting angle of the piezoelectric substrate 7 shown in FIG. 1A is rotated in the range of 0 degrees to -15 degrees around the electric axis (X axis) is provided. Configure. By selecting the cutting angle in this way, it becomes possible to make the first and second coefficients of the polynomial representing the frequency-temperature characteristics of the bending-torsion coupled vibration almost zero, and a piezoelectric vibration element having excellent temperature characteristics can be obtained. effective.
Further, since the first groove portions 22a to 24b constitute the piezoelectric vibration element 1 formed as shown in FIG. 1A, the frequency temperature characteristic of the bending vibration of the bending-torsional coupled vibration is related to the temperature. An effect that a piezoelectric vibration element having tertiary characteristics and excellent temperature characteristics can be obtained, and an advantage that a lead electrode for electrically connecting the excitation electrodes to the flat surfaces of the weight portions 20a and 20b can be formed. is there.

  Further, the first groove portions 22a to 24b constitute the piezoelectric vibration element formed as shown in FIGS. 3A to 3C, so that the frequency temperature characteristics of the main vibration of the flexure-torsion coupled vibration are obtained. Has a third-order characteristic with respect to temperature, and the temperature characteristic is improved. Further, in the example of FIG. 3A, an advantage that a lead electrode for electrically connecting the excitation electrodes can be formed on the flat surface of the weight portion 20a. In the example of FIG. The advantage that the two-groove portion forming mask becomes easy, and in the example of FIG. 3C, the advantage that the flexural vibration frequency and the torsional vibration frequency can be easily combined by appropriately setting the width of the first groove portion. There is also.

FIG. 10 is a cross-sectional view showing a configuration of the piezoelectric vibrator 2 according to the second embodiment of the present invention. The piezoelectric vibrator 2 includes the piezoelectric vibration element 1 and a package that accommodates the piezoelectric vibration element 1. The package includes a package main body 40 formed in a rectangular box shape, and a lid member 52 having a window member 54 made of glass or the like.
As shown in FIG. 10, the package body 40 is formed by laminating a first substrate 41, a second substrate 42, and a third substrate 43 as an insulating substrate, and an aluminum oxide as an insulating material. It is formed by forming a quality ceramic green sheet into a box shape and then sintering it. A plurality of mounting terminals 45 are formed on the outer bottom surface of the first substrate 41.
The central portion of the third substrate 43 is removed, and a metal seal ring 44 such as Kovar is formed on the upper peripheral edge of the third substrate 43.
The third substrate 43 and the second substrate 42 form a recess that accommodates the piezoelectric vibration element 1. A plurality of element mounting pads 47 that are electrically connected to the mounting terminals 45 by conductors 46 are provided at predetermined positions on the upper surface of the second substrate 42.
The positions of the element mounting pads 47 are arranged so as to correspond to pad electrodes (not shown) formed on the support arms 12b and 12c when the piezoelectric vibration element 1 is placed.

The piezoelectric vibrator 2 is configured by applying an appropriate amount of a conductive adhesive 50, for example, an epoxy adhesive, a polyimide adhesive, or a bismaleimide adhesive, to the element mounting pad 47 of the package body 40, and then applying it. The piezoelectric vibration element 1 is placed and a load is applied.
In order to cure the conductive adhesive 50 of the piezoelectric vibrator 1 mounted on the package body 40, it is placed in a high temperature furnace at a predetermined temperature for a predetermined time. After performing the annealing treatment, the laser light is irradiated from above, and the frequency adjustment is performed by evaporating a part of the metal film for frequency adjustment formed on each of the weight portions 20a and 20b and each of the vibrating arms 15a and 15b. A lid member 52 having a glass window 54 is seam welded to a seal ring 44 formed on the upper surface of the package body 40.
Before sealing the through-hole 48 of the package, heat treatment is performed. A metal ball filler 48 a is placed on the stepped portion in the through hole 48 with the package upside down. The filler 48a is preferably a gold-germanium alloy or the like. The filler 48a is irradiated with a laser beam and melted to seal the through hole 48 and to make the inside of the package vacuum. Laser light is irradiated into the package from the outside of the package through the window member 54, and the frequency adjusting metal film formed on the vibrating arms 15a and 15b is evaporated to finely adjust the frequency, thereby completing the piezoelectric vibrator 2.

Deformation of the piezoelectric vibration element 1 when an impact such as dropping is applied to the piezoelectric vibrator 2 having the configuration shown in FIG. When an impact force is applied in the orthogonal direction to the main surface of the package of the piezoelectric vibrator 2, the piezoelectric vibration element 1 has the support arm support portions 12 b and 12 c that are easily deformed with the element mounting pad 47 as a fulcrum. Deforms toward. Next, this deformation is reflected by the outer edge 12 e of the base portion 10, the deformation propagates to the central portion of the base body 12 a, and the whole including the base body 12 a sinks to the bottom surface side of the package body 40. As a result, the vibrating arms 15a and 15b are deformed toward the bottom surface of the package at their distal ends. In other words, the structure of the base 10 is connected to the support arms 12b and 12c through the connecting portion 12d to the base body 12a, so that the applied impact is mitigated by the structure of the base 10.
As shown in the cross-sectional view of FIG. 10, the tuning fork type piezoelectric vibration element 1 in which the bending vibration and the torsion vibration excited by the tuning fork type piezoelectric vibration element are brought close to each other and the bending-torsion coupled vibration is excited. The piezoelectric vibrator 2 is housed in the housing so that a piezoelectric vibrator having a small size, a high Q value, and excellent frequency temperature characteristics can be obtained.

FIG. 11 is a sectional view showing a configuration of a piezoelectric oscillator 3 according to the third embodiment of the present invention. The piezoelectric oscillator 3 includes the piezoelectric vibration element 1 described above, an IC component 78 that excites the piezoelectric vibration element 1, a package body 60 that vacuum seals the piezoelectric vibration element 1 and accommodates the IC component 78, and a window member 75a. And a lid member 75. The method of rough preparation and fine adjustment by irradiating the piezoelectric vibration element 1 with laser light, and the method of sealing the through hole 68 by evacuating the inside of the package are the same as in the case of the piezoelectric vibrator 2. I will omit it. The IC component 78 is electrically connected to the IC component mounting pad 69 of the package body 60 by using a metal bump 76 or the like.
In the piezoelectric oscillator 3 shown in FIG. 11, the IC component 78 is not hermetically sealed. However, the IC component 78 may be disposed inside the package and hermetically sealed.

  As shown in the cross-sectional view of FIG. 11, the tuning fork type piezoelectric vibration element 1 in which bending vibration and torsional vibration are brought close to each other to excite bending-torsion coupled vibration, an IC component 78, and a package 60 that accommodates them. And, there is an effect that a piezoelectric oscillator having a small size and excellent frequency temperature characteristics can be obtained.

FIG. 12 is a diagram showing the configuration of the vibration gyro sensor 4 according to the fourth embodiment of the present invention, with the lid removed. 12A is a plan view of the vibration gyro sensor 4, and FIG. 12B is a cross-sectional view taken along the line PP.
The vibration gyro sensor 4 generally includes a vibration gyro element 80 and a package that houses the vibration gyro element 80. The package includes an insulating substrate (package body) 79 and a lid that hermetically seals the insulating substrate 79.
The vibration gyro element 80 includes a base portion including a base body 81 and a pair of detection vibrating arms 85 a and 85 b that are provided on the same straight line from two opposing edges of the base body 81. . Further, the vibration gyro element 80 is a pair of first connecting arms that are projected from the other two opposite edges of the base body 81 on the same straight line in a direction orthogonal to the detection vibrating arms 85a and 85b. 82a, 82b, and a pair of drive vibration arms 83a, 83b and 84a, 84b that respectively project from the distal ends of the first connecting arms 82a, 82b in both directions orthogonal thereto.

Further, the base portion is a pair of second connecting arms that protrude from the other two opposite edges of the base body 81 in the direction perpendicular to the detection vibrating arms 85a and 85b. Each pair of projections is provided so as to project from the tip of each second connecting arm in both directions orthogonal thereto, and arranged between the detection vibrating arms 85a and 85b and the driving vibrating arms 83a and 3b and 84a and 84b. Support arms 86a, 86b and 87a, 87b.
The excitation electrodes are formed on at least one pair of detection vibrating arms 85a and 85b and each pair of driving vibrating arms 83a and 83b and 84a and 84b. A plurality of electrode pads (not shown) are formed on the support arms 86a and 86b and 87a and 87b, and the electrode pads and the excitation electrodes are electrically connected to each other.

FIG. 12C is a schematic plan view for explaining the operation of the vibrating gyro element. When the angular velocity is not applied to the vibration gyro sensor 4, the driving vibration arms 83a, 83b, 84a, and 84b perform bending vibration in the direction indicated by the arrow E. At this time, the driving vibrating arms 83a and 83b and the driving vibrating arms 84a and 84b vibrate symmetrically with respect to the straight line in the Y′-axis direction passing through the center of gravity G, so that the base main body 81 and the connecting arm 82a. 82b and the vibrating arms for detection 85a and 85b hardly vibrate.
When an angular velocity ω about the Z ′ axis is applied to the vibration gyro sensor 4, Coriolis force acts on the drive vibration arms 83a, 83b, 84a, 84b and the first connection arms 82a, 82b, thereby exciting new vibrations. This vibration is a vibration in the circumferential direction with respect to the center of gravity G. At the same time, the detection vibration arms 85a and 85b are excited to detect vibration in response to this vibration. A detection electrode formed on the vibrating arms for detection 85a and 85b detects the distortion generated by this vibration, and the angular velocity is obtained.

The vibration gyro sensor 4 according to the present invention is characterized in that a weight portion 26 is provided at the tip of the drive vibration arms 83a, 83b, 84a, 84b, and the front and back surfaces of each weight portion 26 are along the length direction of the vibration arm. Thus, the first groove portion 27 is formed symmetrically with respect to the vibration center line. Further, in the driving vibrating arms 83a, 83b, 84a, 84b, second grooves 28 are formed symmetrically with respect to the vibration center line along the length direction of the vibrating arms. The cutting angle θ of the piezoelectric vibration substrate of the vibration gyro element 80, the first groove portion 27 of the weight portion 26, the second groove portion 28 of the drive arms 83a, 83b, 84a, 84b, and the drive arms 83a, 83b, 84a, By appropriately selecting the thickness 84b, the resonance frequencies f _F and f _T of the bending vibration and the torsional vibration excited by the vibration gyro element 80 can be brought close to each other. The two vibration modes are combined to improve the frequency temperature characteristic of the flexural vibration of the main vibration, and by providing the weight portion 26, the drive vibration arm and the detection master arm are shortened, so that the small vibration gyro sensor 4 is provided. Can be configured.

As shown in FIG. 12 (a), a weight portion 26 is formed at the tip of each drive arm vibrating arm 83a to 84b, and linearly along the longitudinal direction of the vibrating arm on the front and back surfaces of the weight portion 26. The extending first groove 27 is formed, and the vibrating gyro element 80 is formed in which the second groove 28 is formed on the front and back surfaces along the vibration center line of each driving arm vibrating arm. When such a vibrating gyro element 80 is configured, the frequency temperature characteristic of the bending vibration, which is the main vibration among the bending-torsional coupled vibrations excited by the driving arm vibrating arms, becomes a third-order characteristic with respect to the temperature. There is an effect that a small vibration gyro element having temperature characteristics can be obtained.
Also, as shown in FIG. 12A, when the vibration gyro sensor is configured by housing the vibration gyro element in a package, the frequency of the main vibration of the bending-torsion coupled vibration excited by the vibration arm for each drive arm. The temperature characteristics are improved, and there is an effect that a vibration gyro sensor reduced in size can be obtained by providing the weight portion.

FIG. 13 is a schematic configuration diagram showing a configuration of an electronic apparatus according to the present invention. The electronic device 5 includes the piezoelectric vibrator 2 described in the second embodiment. Examples of the electronic device 5 using the piezoelectric vibrator 2 include portable electronic devices such as a mobile phone, a digital camera, and a video camera. In these electronic devices 5, the piezoelectric vibrator 5 is used as a reference signal source. By including the small and accurate piezoelectric vibrator 2, an electronic device having a small size, excellent portability, and good characteristics can be provided.
As shown in FIG. 13, by configuring the electronic apparatus including the piezoelectric vibrator 2 of FIG. 10, there is an effect that the stability of the frequency source of the electronic apparatus is improved. In addition, by configuring the electronic device including the vibration gyro sensor of FIG. 12A, there is an effect that the change in sensitivity of the angular velocity due to temperature can be reduced.

DESCRIPTION OF SYMBOLS 1 ... Piezoelectric vibration element, 2 ... Piezoelectric vibrator, 3 ... Piezoelectric oscillator, 4 ... Vibration gyro sensor, 5 ... Electronic device, 7 ... Piezoelectric substrate, 10 ... Base part, 12a ... Base part main body, 12b, 12c ... Support arm, 12d ... Connecting part, 12e ... outer edge, 15 ... beam, 15a, 15b ... vibrating arm, 17a, 17b, 18a, 18b, 28 ... second groove part, 20a, 20b, 26 ... weight part, 21a, 21b, 21 'a, 21'b ... recess, 22a, 22b, 24a, 24b, 27 ... first groove, 25 ... electrode, 30, 32, 34, 36 ... excitation electrode, 40, 60, 79 ... package body, 41 ... 1st board | substrate, 42 ... 2nd board | substrate, 43 ... 3rd board | substrate, 44 ... metal seal ring, 45 ... mounting terminal, 46 ... conductor, 47 ... element mounting pad, 48, 68 ... through-hole, 48a ... filling 50, conductive adhesive, 52, 5 ... Lid member, 54, 75a ... Window member, component mounting pad ... 69, 78 ... IC component, 80 ... Vibrating gyro element, 81 ... Base body, 82a, 82b ... First connecting arm, 83a, 83b, 84a, 84b ... vibration arm for driving, 85a, 85b ... vibration arm for detection, 86a, 86b, 87a, 87b ... support arm, C ... vibration center line

Claims (10)

The base,
A pair of vibrating arms extending in a first direction from the base, arranged in a second direction orthogonal to the first direction, and vibrating by combining bending vibration and torsional vibration;
Including
The vibrating arm is a plan view,
A weight part;
An arm portion arranged on the base side from the weight portion;
Including
The weight portion is
A first groove portion extending from the outer edge on the opposite side to the arm portion side to the middle portion is provided on at least one of the front surface and the back surface that are in a front-back relationship with each other,
The arm is
A second groove is provided along the first direction on at least one of the front and back surfaces that are in a front-back relationship with each other,
Vibrating elements, characterized in that electrodes are provided on the a side and the surface of the arm portion which connects the said rear face, said second groove of the inner surface. The base,
A pair of vibrating arms extending in a first direction from the base, arranged in a second direction orthogonal to the first direction, and vibrating by combining bending vibration and torsional vibration;
Including
The vibrating arm is a plan view,
A weight part;
An arm portion arranged on the base side from the weight portion;
Including
The weight portion is
A first groove is provided on at least one of the front and back surfaces that are in a relationship of front and back,
The arm is
A second groove is provided along the first direction on at least one of the front and back surfaces that are in a front-back relationship with each other,
The first groove portion is connected to the second groove portion, and extends to an outer edge of the weight portion opposite to the arm portion side,
The vibrating element is characterized in that an electrode is provided on a side surface connecting the front surface and the back surface of the arm portion and an inner surface of the second groove portion. In claim 1 or 2 ,
At least a part of the first groove is wider than the second groove in the second direction. In any one of Claims 1 thru | or 3 ,
The vibrating element is characterized in that the weight portion is wider in the second direction than the arm portion. In any one of Claims 1 thru | or 4 ,
The vibration element is composed of a quartz plate,
An oscillating element characterized in that an angle formed between a normal line of a main surface of the quartz plate and an optical axis of the quartz crystal is in a range of 0 degrees to -15 degrees. In any one of Claims 1 thru | or 5 ,
The base is
A base body from which the vibrating arm extends;
A connecting portion that extends from an end of the base body opposite to the vibrating arm in a plan view and is narrower than a width of the base body along the second direction;
A support arm extending from an end of the connecting portion opposite to the base in a plan view;
A vibration element comprising: The vibration element according to any one of claims 1 to 6 ,
A substrate on which the vibration element is mounted;
A vibrator characterized by comprising: The vibration element according to any one of claims 1 to 6 ,
An IC for driving the vibration element;
An oscillator comprising: Gyro sensor, characterized in that it comprises a vibrating element according to any one of claims 1 to 6. An electronic apparatus characterized by comprising a vibration device according to any one of claims 1 to 6.

Images