JP2007093400A - Bending vibration type piezoelectric vibration chip, tuning fork type piezoelectric vibrator, and angular speed detection sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bending vibration type piezoelectric vibration chip capable of reducing a residual stress after forming electrode layers and substrate metal layers and suppressing increase of a CI value, a tuning fork type piezoelectric vibrator using it and an angular speed detection sensor. <P>SOLUTION: Since the substrate metal layers 20A, 20B are formed of nickel having a smaller residual stress than chrome, even if a mechanical stress is applied to a substrate 2 and the electrode layers 30A, 30B by bending vibration, increase of the CI value can be suppressed. Since the substrate metal layers 20A, 20B are formed of nickel having lower diffusion speed than chrome, a phenomenon is reduced, wherein nickel is diffused into the electrode layers 30A, 30B formed of gold and thereby the substrate metal layers 20A, 20B are thinned. Consequently, if nickel is used for the substrate metal layers 20A, 20B, even if a mechanical stress is applied to the substrate 2 and the electrode layers 30A, 30B by the bending vibration, adhesiveness between the substrate 2 and the electrode layers 30A, 30B can be secured. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a bending vibration type piezoelectric vibrating piece, a tuning fork type piezoelectric vibrator using the same, and an angular velocity detection sensor.

  Conventionally, tuning fork type piezoelectric vibrators have been used as timepiece vibrators. In recent years, with the miniaturization of electronic equipment on which this is mounted, tuning fork type piezoelectric vibrators and flexural vibration type piezoelectric vibrating reeds used therefor are required to be further downsized.

  On the other hand, an angular velocity detection sensor has been conventionally used for detecting camera shake such as a camera or a video camera, or for detecting a traveling direction for a GPS (Global Positioning System) or a car navigation system. There are a wide variety of electronic devices equipped with angular velocity detection sensors, and further miniaturization is required. The angular velocity detection sensor and the flexural vibration type piezoelectric vibrating piece used therefor are required to be further downsized. In addition, the environment in which these electronic devices are used is further expanding.

Quartz is mainly used for the substrate of the flexural vibration type piezoelectric vibrating piece used in the tuning fork type piezoelectric vibrator and the angular velocity detection sensor. The electrode of the flexural vibration type piezoelectric resonator element is a base metal layer intended to ensure adhesion between the crystal as the substrate and the gold as the electrode layer in order to ensure the adhesion between the crystal and the gold. As a result, a chromium layer is formed (see, for example, Patent Document 1).
Here, in the bending vibration type piezoelectric vibrating piece, since the substrate and the electrode layer are easily subjected to mechanical stress due to bending vibration, the residual after the formation of the electrode layer and the base metal layer compared to the thickness-slip type piezoelectric vibrating piece. It is necessary that the stress is small.

JP 2001-165664 A (page 13, FIG. 1)

  However, when chromium is used as the base metal layer, the residual stress after the formation of the electrode layer and the base metal layer increases, and as a result, the crystal impedance value (hereinafter referred to as “CI value”) increases. There was a problem.

  An object of the present invention is to provide a flexural vibration type piezoelectric vibrating piece that can reduce residual stress after formation of an electrode layer and a base metal layer and suppress an increase in CI value, a tuning fork type piezoelectric vibrator using the same, and an angular velocity It is to provide a detection sensor.

  The bending vibration type piezoelectric vibrating piece of the present invention includes a base and a substrate having a vibration arm that is bent and formed extending from the base, and an electrode provided on the substrate, the electrode including an electrode layer And the base metal layer, the electrode layer is made of gold, and the base metal layer is made of nickel.

  According to the present invention, the base metal layer is formed of nickel having a smaller residual stress than chromium. Therefore, even if the substrate and the electrode layer are subjected to mechanical stress due to bending vibration, an increase in CI value is suppressed.

In the present invention, the substrate is preferably a crystal.
In the present invention, the fluctuation of the CI value with respect to the temperature change is further reduced.

The tuning fork type piezoelectric vibrator of the present invention is characterized by including the above-described bending vibration type piezoelectric vibrating piece.
According to the present invention, a tuning fork type piezoelectric vibrator having the above-described effects can be obtained.

An angular velocity detection sensor according to the present invention includes the above-described flexural vibration type piezoelectric vibrating piece.
According to the present invention, an angular velocity detection sensor having the above-described effects can be obtained.

Hereinafter, embodiments according to the present invention will be described with reference to the drawings.
The inventors of the present application have hypothesized that the magnitude of residual stress after the formation of the base metal layer and the electrode layer is a cause of the CI value variation with respect to the increase in CI value and temperature.
In order to prove this hypothesis, the following experiment was conducted. A sample was prepared by forming a chromium layer with a thickness of 50 nm as a base metal layer on one side of a quartz substrate and forming a gold layer with a thickness of 50 nm on the chromium layer. In addition, another sample was prepared in which a nickel layer having a thickness of 50 nm was formed as a base metal layer on one surface of a quartz substrate, and a gold layer having a thickness of 50 nm was formed thereon. The warpage of these two samples was measured using a non-contact three-dimensional measuring apparatus. The result is shown in FIG. FIG. 8A shows the measurement result of the warpage of the sample whose base metal layer is the chromium layer, and FIG. 8B shows the measurement result of the warpage of the sample whose base metal layer is the nickel. For both samples, an area of 40 mm × 30 mm was measured. The vertical axis represents the amount of warpage, and the unit is mm. All layers are formed by sputtering, and the conditions are the same.

It can be seen from FIG. 8 that the warpage of the substrate when the base metal layer is a nickel layer is as small as about 1/8 times the warpage of the substrate when the base metal layer is a chromium layer.
The reason for this is as follows.
It is known that the bonding force between the nickel layer and the crystal is smaller than the bonding force between the chromium layer and the crystal. As a result, the residual stress after the formation of the base metal layer and the gold layer when the base metal layer is a nickel layer is smaller than that when the base metal layer is a chromium layer.
From the above results, it can be expected that the increase in CI value is suppressed.
In the following, a configuration example of a piezoelectric vibrator or angular velocity detection sensor including a bending vibration type piezoelectric vibrating piece and a bending vibration type piezoelectric vibrating piece is shown, and an example in which an increase in CI value can be suppressed is shown.

(First embodiment)
FIG. 1 shows a tuning fork type piezoelectric vibrator 1 according to the first embodiment.
FIG. 1A is a schematic plan view of the tuning fork type piezoelectric vibrator 1, and FIG. 1B is a cross-sectional view taken along line AA in FIG.
In FIG. 1, the tuning fork type piezoelectric vibrator 1 includes a tuning fork type piezoelectric vibrating piece 10 that is a bending vibration type piezoelectric vibrating piece, a package 50, and a lid body 60. The tuning fork type piezoelectric vibrating piece 10 is installed in a storage chamber 70 formed in the package 50 and sealed with a lid body 60 joined by a brazing agent or the like.

  The package 50 is formed by laminating a first laminated substrate 51, a second laminated substrate 52, and a third laminated substrate 53. These laminated substrates are formed from a ceramic sheet made of, for example, an aluminum oxide that is an insulating material. The storage chamber 70 is formed by punching the second laminated substrate 52 and the third laminated substrate 53 in accordance with the shape of the storage chamber 70. The package 50 is obtained by laminating these laminated substrates 51 to 53 and then sintering them.

  The second laminated substrate 52 is formed with a protruding portion 54 that protrudes into the storage chamber 70. The protruding portion 54 is provided with an electrode portion 55. The electrode portion 55 is formed by nickel plating and gold plating on tungsten metallized on the protruding portion 54.

In the tuning fork type piezoelectric vibrating piece 10, the base 11 of the tuning fork type piezoelectric vibrating piece 10 is fixed to the protruding portion 54 by a conductive adhesive 56, and an electrode portion 55 and an electrode (not shown) provided on the tuning fork type piezoelectric vibrating piece 10 are provided. It is installed electrically connected. The electrode portion 55 is electrically connected to the outside, and a driving voltage is supplied to the tuning fork type piezoelectric vibrating piece 10.
In addition, as the conductive adhesive 56, a synthetic resin as an adhesive having bonding strength can be used by containing fine conductive particles such as silver. As the synthetic resin, a silicon-based, epoxy-based or polyimide-based conductive adhesive can be used.

Hereinafter, the tuning fork type piezoelectric vibrating piece 10 will be described in detail with reference to the drawings.
FIG. 2A is a schematic plan view of the tuning fork type piezoelectric vibrating piece 10 used in the tuning fork type piezoelectric vibrator 1.
FIG. 2B is a BB cross-sectional view for explaining in detail the electrode 3 formed on the surface of the tuning-fork type piezoelectric vibrating piece 10 in FIG.

In FIG. 2A, the substrate 2 of the tuning-fork type piezoelectric vibrating piece 10 has a rectangular base 11 and a pair of drive arms 12A and 12B that are vibration arms that bend and vibrate. The drive arms 12A and 12B are formed in a rectangular parallelepiped extending from the base portion 11.
The substrate 2 is formed by etching a quartz plate cut out from a quartz single crystal. A single crystal of quartz has a characteristic that when an electric field is generated in a direction called an electric axis, mechanical strain is generated in a direction called a mechanical axis.

In FIG. 2B, the cross-sections of the drive arms 12A and 12B are formed in a rectangular shape. Electrodes 3 for driving the tuning-fork type piezoelectric vibrating piece 10 are provided on each of the four sides of the drive arms 12A and 12B. These electrodes 3 include driving electrode layers 30A and 30B and base metal layers 20A and 20B as bases of the electrode layers 30A and 30B. Base metal layers 20A and 20B are formed so as not to contact each other, and electrode layers 30A and 30B are formed thereon.
A voltage having the same polarity is applied to the electrode layer 30A, and a voltage having a polarity opposite to that of the electrode layer 30A is applied to the electrode layer 30B. At this time, the electrode layer 30A, the base metal layer 20A, and the electrode layer 30B and the base metal layer 20B are formed so that the direction of the electric field applied to the drive arm 12B is opposite to the direction of the electric field applied to the drive arm 12A.

The base metal layer 20A and the electrode layer 30A are formed on two opposing side surfaces, and the base metal layer 20B and the electrode layer 30B are formed on the other two opposing side surfaces.
The base metal layers 20A and 20B are formed by vapor deposition or sputtering of nickel. The electrode layers 30A and 30B are formed by vapor deposition or sputtering of gold.
Here, the thickness of the electrode layers 30A and 30B is preferably 50 nm or more and 100 nm or less. The thickness of the base metal layers 20A and 20B is preferably 10 nm or more and 30 nm or less.

Next, the vibration of the drive arms 12A and 12B will be described.
When a positive voltage is applied to the electrode layer 30A of the drive arms 12A and 12B and a negative voltage is applied to the electrode layer 30B, an electric field acts from the electrode layer 30A to the electrode layer 30B as indicated by a dashed-dotted arrow YC. At this time, shrinkage distortion occurs in the direction of arrow DC on the right side of the drive arm 12A and the left side of the drive arm 12B. At the same time, an elongation distortion occurs in the direction of the arrow DL on the left side of the drive arm 12A and the right side of the drive arm 12B. As a result, the drive arms 12A and 12B are bent in the direction indicated by the alternate long and short dash line YA in FIG.

  When the voltage applied to the electrode layer 30A and the voltage applied to the electrode layer 30B have the same magnitude and different polarities, and an alternating voltage is applied to the electrode layer 30A and the electrode layer 30B, the drive arm 12A, 12B vibrates by repeatedly repeating the state indicated by the one-dot chain line PA and the state indicated by the two-dot chain line PB. That is, the tuning fork type piezoelectric vibrating piece 10 is flexibly vibrated.

  The CI value at room temperature when the base metal layer was nickel was about 80% of the CI value when the base metal layer was chromium.

According to the tuning fork type piezoelectric vibrator 1 of the present embodiment, the following effects are obtained.
(1) Since the base metal layers 20A and 20B are formed of nickel whose residual stress is smaller than that of chromium, the CI value increases even if the substrate 2 and the electrode layers 30A and 30B are subjected to mechanical stress by bending vibration. Can be suppressed.

  (2) Since the base metal layers 20A and 20B are formed of nickel whose diffusion rate is slower than that of chromium, the nickel diffuses into the electrode layers 30A and 30B formed of gold and the base metal layers 20A and 20B become thin. This phenomenon is reduced. Therefore, if nickel is formed as the base metal layers 20A and 20B, even if the substrate 2 and the electrode layers 30A and 30B are subjected to mechanical stress due to bending vibration, the adhesion between the substrate 2 and the electrode layers 30A and 30B. Can be secured.

  (3) If the thickness of the base metal layers 20A and 20B is 10 nm or more, the adhesion between the substrate 2 and the electrode layers 30A and 30B can be maintained. Moreover, if the thickness of the base metal layers 20A and 20B is 30 nm or less, vibration efficiency can be maintained.

(Second embodiment)
FIG. 3 shows an angular velocity detection sensor 100 according to the second embodiment.
FIG. 3A is a schematic plan view of the angular velocity detection sensor 100, and FIG. 3B is a cross-sectional view taken along the line CC in FIG.
In FIG. 3, the angular velocity detection sensor 100 includes a bending vibration type piezoelectric vibrating piece 110, a package 150, a lid body 160, a support substrate 180, and a lead wire 181. The bending vibration type piezoelectric vibrating piece 110 is installed in a storage chamber 170 formed in the package 150. The bending vibration type piezoelectric vibrating piece 110 is sealed by a lid body 160 joined by a brazing agent or the like.

In FIG. 3, the package 150 is formed by laminating a plurality of laminated substrates (not shown). The package 150 is obtained by laminating and laminating these laminated substrates. The storage chamber 170 is formed by punching a laminated substrate in accordance with the shape of the storage chamber 170.
In the storage chamber 170, a support substrate 180 is installed, and a plurality of lead wires 181 are installed thereon. The base 111 of the flexural vibration type piezoelectric vibrating piece 110 is fixed to the lead wire 181 and is electrically connected. The lead wire 181 is electrically connected to the outside through a wiring (not shown) of the support substrate 180. A drive voltage is supplied to the flexural vibration type piezoelectric vibrating piece 110 through these wires, and an electric signal such as a detection voltage is detected.

Hereinafter, the flexural vibration type piezoelectric vibrating piece 110 will be described in detail with reference to the drawings.
FIG. 4A is a schematic plan view showing the flexural vibration type piezoelectric vibrating piece 110 used in the angular velocity detection sensor 100.
FIG. 4B is a DD cross-sectional view in FIG. 4A for explaining in detail the electrode 103 formed on the surface of the bending vibration type piezoelectric vibrating piece 110.

  4A, the substrate 102 of the bending vibration type piezoelectric vibrating piece 110 includes a rectangular base 111 located at the center, a detection arm 113 that is a pair of bending vibration vibration arms, and a pair of support arms 114. A pair of drive arms 112A and a pair of drive arms 112B are provided. The pair of detection arms 113 are formed in a rectangular parallelepiped shape so as to extend in a direction facing the base portion 111. The pair of support arms 114 is a rectangular parallelepiped extending from the base portion 111 in a direction substantially orthogonal to the pair of detection arms 113. The pair of drive arms 112 </ b> A and the pair of drive arms 112 </ b> B are formed as a rectangular parallelepiped extending in a direction substantially orthogonal to the support arm 114. The substrate 102 is formed from a single crystal of quartz by the same method as in the first embodiment, and has similar characteristics.

In FIG. 4B, the detection arm 113 has a rectangular cross section. Electrodes 103 for detecting the angular velocity ω are provided on each of the four sides of the detection arm 113. These electrodes 103 include electrode layers 130A and 130B for detection and base metal layers 120A and 120B as bases for the electrode layers 130A and 130B. Base metal layers 120A and 120B are formed so as not to contact each other, and electrode layers 130A and 130B are formed thereon.
The base metal layers 120A and 120B and the electrode layers 130A and 130B are formed by the same method as in the first embodiment.
The driving arms 112A and 112B are also provided with driving electrodes 103, and the base metal layers 120A and 120B and the electrode layers 130A and 130B are formed in the same manner as the detection arm 113.
Here, the thicknesses of gold as the electrode layers 130A and 130B and nickel as the base metal layers 120A and 120B are the same as in the first embodiment.

Next, detection of the angular velocity ω by such bending of the detection arm 113 will be described.
The electrode layers 130A provided on the opposite side surfaces of the detection arm 113 are provided to have the same potential. The electrode layer 130B provided on the other opposing side surface is provided so as to have the same potential different from the potential of the electrode layer 130A.
When the flexural vibration type piezoelectric vibrating piece 110 rotates at an angular velocity ω in the clockwise direction of the Z axis, a Coriolis force is generated. Due to the Coriolis force, the detection arm 113 bends as indicated by a one-dot chain line arrow YE shown in FIG. Further, when a rotational motion is performed at an angular velocity ω in the Z-axis counterclockwise direction, a Coriolis force is generated. Due to the Coriolis force, the detection arm 113 bends as indicated by a two-dot chain line arrow YD shown in FIG. The voltage generated by the generation of the electric field accompanying this bending can be detected as an electric signal corresponding to the angular velocity ω.
Here, when the bending vibration type piezoelectric vibrating piece 110 is not rotating, the detection arm 113 is not bent or bent.

FIG. 5 shows the temperature characteristic change of the CI value and the temperature characteristic change of the detection voltage Vo.
FIG. 5A shows that nickel (Ni) or chromium (Cr) of the base metal layers 120A and 120B is the same under the condition that the thickness of the gold (Au) of the electrode layers 130A and 130B of the detection arm 113 is the same. FIG. 5B is a diagram showing a change in temperature characteristic of the normalized CI value when the thickness is provided, and FIG. 5B is a diagram showing a change in temperature characteristic of the normalized detection voltage Vo at this time. Here, the normalized CI value is a value obtained by dividing each CI value by using the CI value at 0 ° C. as the denominator when the underlying metal layer is chromium. The normalized detection voltage Vo is a value obtained by dividing each detection voltage Vo by using the detection voltage Vo at 0 ° C. as a denominator when the underlying metal layer is chromium.
In FIG. 5A, the temperature characteristic change of the normalized CI value when nickel is provided on the base metal layers 120A and 120B is the temperature characteristic of the normalized CI value when chromium is provided on the base metal layers 120A and 120B. Stable compared to changes.
In FIG. 5B, the temperature characteristic of the normalized detection voltage Vo when nickel is provided on the base metal layers 120A and 120B is the temperature characteristic of the normalized detection voltage Vo when chromium is provided on the base metal layers 120A and 120B. Stable compared to characteristics.

According to the angular velocity detection sensor 100 of the second embodiment, in addition to the effects of the first embodiment, there are the following effects.
(4) The quartz crystal as the substrate 2 constituting the detection arm 113, the nickel of the base metal layers 120A and 120B, and the gold of the electrode layers 130A and 130B are equivalent in terms of the thermal expansion coefficient. It is in. For this reason, the influence by the surrounding temperature change is reduced, and the CI value of the flexural vibration type piezoelectric vibrating piece 110 is stably maintained. In addition, the voltage detected when the angular velocity detection sensor 100 is stationary while not rotating can be detected stably, and malfunctions when stationary can be prevented.

It should be noted that the present invention is not limited to the above-described embodiments, and modifications, improvements, and the like within the scope that can achieve the object of the present invention are included in the present invention.
For example, the package for accommodating the tuning-fork type piezoelectric vibrating piece 10 is not limited to the above-described structure, but the tuning-fork type piezoelectric vibrating piece 10 is bonded to a flat substrate made of glass or metal material, and the concave portion is formed. It is also possible to use a package that is sealed with a box-shaped lid.
Alternatively, a tuning fork type piezoelectric vibrating piece may be joined to a metal cylindrical member using a conductive adhesive or solder and sealed with a metal cylindrical case.

(Modification 1)
Hereinafter, a flexural vibration type piezoelectric vibrating piece 210 that can be used in the angular velocity detection sensor 100 will be described in detail with reference to the drawings.
FIG. 6A is a schematic plan view of the flexural vibration type piezoelectric vibrating piece 210.
FIG. 6B is a cross-sectional view taken along line EE in FIG. 6A for explaining in detail the electrode 203 formed on the surface of the flexural vibration type piezoelectric vibrating piece 210.

  In FIG. 6A, the substrate 202 of the bending vibration type piezoelectric vibrating piece 210 includes a rectangular base portion 211, a detection arm 213 that is a vibration arm that bends and vibrates, and a drive arm 212. The base 211, the detection arm 213, and the drive arm 212 are formed in the same manner as in the first embodiment.

In FIG. 6B, the detection arm 213 has a rectangular cross section. Electrodes 203 for detecting the angular velocity ω are provided on the side surface of the detection arm 213 on the drive arm 212 side and the side surface of the detection arm 213 facing this side surface.
Further, the electrode 203 provided on the side surface of the detection arm 213 is divided into two parts on the same side surface, and is formed of the electrode layer 231A, the base metal layer 221A, the electrode layer 231B, and the base metal layer 221B.
The electrode layer 231A provided on the side surface of the detection arm 213 is provided at the same potential, and the electrode layer 231B is provided at the same potential.
The electrode layers 231A and 231B formed on the opposing side surfaces of the detection arm 213 are formed so as to be able to detect a voltage generated by the generation of an electric field accompanying the rotational motion at the angular velocity ω.

The cross section of the drive arm 212 is formed in a rectangular shape. Electrodes 203 are provided on each of the four sides of the drive arm 212. These electrodes 203 include driving electrode layers 230A and 230B and base metal layers 220A and 220B as bases of the electrode layers 230A and 230B.
The base metal layers 220A and 220B and the electrode layers 230A and 230B are formed by the same method and thickness as the drive arm 12A shown in the first embodiment.

Next, driving of the driving arm 212 will be described.
When an alternating voltage is applied to the electrode layers 230A and 230B constituting the drive arm 212 in the same manner as in the first embodiment, the drive arm 212 performs bending vibration similar to that of the drive arm 12A in the first embodiment.
As a result, the detection arm 213 bends in the same manner as the drive arm 12B so as to maintain equilibrium with the drive arm 212.

The detection of the angular velocity ω by bending the detection arm 213 will be described.
When the bending vibration type piezoelectric vibrating piece 210 rotates in the Y-axis clockwise direction with an angular velocity ω, Coriolis force is generated, and the detection arm 213 bends in the Z-axis plus direction. Further, when a rotational motion with an angular velocity ω is performed in the counterclockwise direction of the Y axis, a Coriolis force is generated, and the detection arm 213 is bent in the negative direction of the Z axis. The voltage generated by the generation of the electric field accompanying this bending can be detected as an electric signal corresponding to the angular velocity ω.

  At this time, the drive arm 212 is bent in the Z axis minus direction (not shown) or the Z axis plus direction (not shown) so as to keep balance with respect to the bending of the detection arm 213, and the detection arm 213 and the drive arm 212 are complicated bent (not shown). Vibrate.

(Modification 2)
Hereinafter, a flexural vibration type piezoelectric vibrating piece 310 that can be used in the angular velocity detection sensor 100 will be described in detail with reference to the drawings.
FIG. 7A is a schematic plan view of the flexural vibration type piezoelectric vibrating piece 310.
FIG. 7B is a cross-sectional view taken along the line FF in FIG. 7A for explaining in detail the electrode 303 formed on the surface of the flexural vibration type piezoelectric vibrating piece 310.

  In FIG. 7, the substrate 302 of the bending vibration type piezoelectric vibrating piece 310 includes a rectangular base 311 located at the center, detection arms 313A and 313B which are a pair of vibration arms that bend and vibrate, and a pair of drive arms 312A and 312B. And. The detection arms 313A and 313B are formed in a rectangular parallelepiped extending from the base 311. The drive arms 312A and 312B are formed in a rectangular parallelepiped shape so as to extend from the base 311 in substantially opposite directions to the detection arms 313A and 313B.

In FIG. 7B, the detection arms 313A and 313B have a rectangular cross section. An electrode 303 for detecting the angular velocity ω is provided on the side surface of the detection arm 313A and the side surface of the detection arm 313B facing the side surface.
Further, the electrode 303 provided on the side surfaces of the detection arms 313A and 313B is divided into two on the same side surface, and an electrode layer 331A and a base metal layer 321A, and an electrode layer 331B and a base metal layer 321B are formed.
Base metal layers 321A and 321B and electrode layers 331A and 331B are formed on the side surfaces of the detection arms 313A and 313B in the same arrangement as the detection arm 213 of the first modification. Further, the base metal layers 321A and 321B and the electrode layers 331A and 331B formed on the detection arm 313B are formed in a line-symmetric arrangement with the electrode 303 of the detection arm 313A.

The electrode layers 331A provided on the side surfaces of the detection arms 313A and 313B are provided at the same potential, and the electrode layers 331B are provided at the same potential.
The electrode layers 331A and 331B formed on the opposing side surfaces of the detection arms 313A and 313B are formed so as to be able to detect a voltage generated by the generation of an electric field accompanying the rotational motion at the angular velocity ω.

  Here, by applying an alternating voltage to the drive electrodes (not shown) of the drive arms 312A and 312B, the drive arms 312A and 312B bend and vibrate similarly to the drive arms 12A and 12B of the first embodiment. .

Next, detection of the angular velocity ω by bending the detection arms 313A and 313B will be described.
When the bending vibration type piezoelectric vibrating piece 310 rotates at an angular velocity ω, a Coriolis force is generated, and the detection arm 313A and the detection arm 313B bend in the same manner as the detection arm 213 and the drive arm 212 of the first modification. The voltage generated by the generation of the electric field accompanying this bending can be detected as an electric signal corresponding to the angular velocity ω.
Here, when the flexural vibration type piezoelectric vibrating piece 310 is not rotating, the detection arms 313A and 313B are not flexed and flexed.

  Further, the drive arms 312A and 312B are bent in the same manner as the detection arm 213 and the drive arm 212 of the modified example 1 so as to keep equilibrium with respect to the bending of the detection arms 313A and 313B. Complex bending vibration (not shown) occurs.

  The tuning fork type piezoelectric vibrating piece 10 of the present invention is not limited to the tuning fork type piezoelectric vibrator 1 described above, and can be used for, for example, a real time clock module.

  When the angular velocity detection sensor 100 of the present invention is arranged and mounted on a device, the influence of a change in ambient temperature such as a heat source in the device or heat convection is reduced, and there is an effect that the arrangement location is not selected.

  When using or installing a device using the angular velocity detection sensor 100 of the present invention, there is an effect that the influence due to a temperature change around the device is reduced and the use range or the installation range is expanded.

The best method for carrying out the present invention has been disclosed in the above description, but the present invention is not limited to this. That is, the present invention has been mainly described with reference to specific embodiments, but the materials, configurations, and manufactures used for the above-described embodiments without departing from the scope of the technical idea and object of the present invention. Various modifications can be made by those skilled in the art in the method and other details.
Accordingly, the description of the materials, configurations, manufacturing methods, and the like disclosed above is exemplary for easy understanding of the present invention, and is not intended to limit the present invention. Descriptions excluding some or all of the limitations on the materials and their configurations are included in the present invention.

(A) is a top view which shows the outline of the tuning fork type piezoelectric vibrator which concerns on 1st embodiment of this invention, (b) is outline AA sectional drawing. (A) is a top view sectional drawing which shows the outline of the tuning fork type piezoelectric vibrating piece of this invention, (b) is a schematic BB sectional drawing. (A) is a top view which shows the outline of the angular velocity detection sensor which concerns on 2nd embodiment of this invention, (b) is a schematic CC sectional drawing. (A) is a top view which shows the outline of the bending vibration type piezoelectric vibrating piece of this invention, (b) is a schematic DD sectional drawing. (A) is a temperature characteristic diagram of the CI value, (b) is a temperature characteristic diagram of the voltage Vo. (A) is a top view which shows the outline of the modification 1 of this invention, (b) is a schematic EE sectional drawing. (A) is a top view which shows the outline of the modification 2 of this invention, (b) is an outline FF sectional drawing. (A) is the figure which showed the curvature amount when a base metal layer was made into chromium, (b) was the figure which showed the curvature amount when a foundation metal layer was made into nickel.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Tuning fork type piezoelectric vibrator, 10 ... Tuning fork type piezoelectric vibrating piece as bending vibration type piezoelectric vibrating piece, 11 ... Base, 12A, 12B, 212 ... Vibration arm, 2 ... Substrate, 3, 103 ... Electrode, 20A, 20B , 120A, 120B ... underlying metal layer, 30A, 30B, 130A, 130B ... electrode layer, 100 ... angular velocity detection sensor, 110 ... flexural vibration type piezoelectric vibrating piece.

Claims (4)

A substrate having a base and a vibration arm that is formed to extend from the base and vibrates, and an electrode provided on the substrate,
The electrode includes an electrode layer and a base metal layer,
The electrode layer is made of gold;
The flexural vibration type piezoelectric vibrating piece, wherein the base metal layer is made of nickel. The bending vibration type piezoelectric vibrating piece according to claim 1, wherein the substrate is a crystal. A tuning-fork type piezoelectric vibrator comprising the bending vibration type piezoelectric vibrating piece according to claim 1. An angular velocity detection sensor comprising the bending vibration type piezoelectric vibrating piece according to claim 1.