JP2010226608A - Bending vibrator and oscillator using the same - Google Patents

Abstract

Disclosed are a small flexural vibration piece in which a decrease in Q value is suppressed, and an oscillator using the same.
A tuning fork type crystal vibrating piece 50 has a tuning fork type outer shape including a base portion 52 and a pair of vibrating arms 53 and 54 extending from one end side of the base portion 52. On one main surface side of 54, in a region including the vicinity of the base of each vibrating arm 53, 54 with the base 52, one linear shape provided along the longitudinal direction of each vibrating arm 53, 54. Bottomed grooves 56a, 5
7a and embedded members 56b with high thermal conductivity such as gold embedded in the grooves 56a and 57a,
Heat conduction paths 56 and 57 composed of 57b are formed. Similarly, on the other main surface side of each vibrating arm 53, 54, bottomed grooves 66a, 67a provided with openings at positions opposed to the grooves 56a, 57a on the one main surface side; Thermal conduction paths 66 and 67 are formed of embedded members 66b and 67b made of gold embedded in the grooves 66a and 67a.
[Selection] Figure 1

Description

The present invention relates to a flexural vibration piece that vibrates in a flexural vibration mode and an oscillator using the flexural vibration piece.

Conventionally, as a flexural vibration piece that vibrates in a flexural vibration mode, for example, a pair of vibrating arms are extended in parallel from a base made of a base material for a flexural vibrator such as a piezoelectric material, and the vibrating arms are horizontally oriented. Tuning-fork type bending vibration pieces that vibrate in directions toward or away from each other are widely used. When the vibration arm of the tuning-fork type bending vibration piece is excited, if the vibration energy is lost, it causes a decrease in the performance of the vibration piece, such as an increase in CI (Crystal Impedance) value and a decrease in Q value. Therefore, in order to prevent or reduce such vibration energy loss,
Various ideas have been made conventionally.

For example, a tuning-fork type crystal vibrating piece in which cut portions or cut grooves having a predetermined depth are formed on both sides of a base portion from which a vibrating arm extends is known (see, for example, Patent Document 1 and Patent Document 2). This tuning fork type crystal vibrating piece improves the confinement effect of vibration energy by suppressing the leakage of vibration from the base portion by the cut portion or the cut groove when the vibration of the vibrating arm also includes a vertical component. The value is controlled, and the variation of the CI value between the resonator elements is prevented.

In addition to this mechanical vibration energy loss, a temperature difference occurs between the compression part where the compressive stress of the vibrating arm that vibrates and the extension part where the tensile stress acts, and acts to alleviate this temperature difference. Loss of vibration energy also occurs due to heat conduction. This decrease in the Q value caused by heat conduction is called a thermoelastic loss effect.
In order to prevent or suppress such a decrease in the Q value due to the thermoelastic loss effect, a tuning-fork type vibrating piece in which a groove or a hole is formed on the center line of a vibrating arm (vibrating beam) having a rectangular cross section is disclosed in, for example, a patent. It is introduced in Reference 3.

According to Patent Document 3, from the relational expression of strain and stress that is well known in the case of solid internal friction that is generally caused by a temperature difference, the thermoelastic loss is the frequency of the vibration piece in the bending vibration mode. It is described that the Q value becomes minimum at a relaxation frequency fm = 1 / (2πτ) (where τ is a relaxation time) when changed. The relationship between the Q value and the frequency is generally expressed as a curve F in FIG. 8 (see, for example, Non-Patent Document 1). In the figure, the frequency at which the Q value becomes the minimum Q ₀ is the thermal relaxation frequency f ₀ (= 1 / (2πτ)), that is, the thermal relaxation frequency f _0.
Is the same as the relaxation frequency fm.

Specifically, referring to the drawings, in FIG.
Comprises two parallel vibrating arms 3, 4 extending from the base 2, and linear grooves or holes 6, 7 are provided on the center lines of the respective vibrating arms 3, 4. When a predetermined drive voltage is applied to excitation electrodes (not shown) provided on both main surfaces (the same surfaces as the grooves or holes 6 and 7 forming surface) of the respective vibrating arms 3 and 4 of the tuning fork type crystal vibrating piece 1, the vibrating arms 3 and 4 bend and vibrate in directions toward or away from each other, as indicated by imaginary lines (two-dot chain lines) and arrows in the figure.

Due to this bending vibration, mechanical strain is generated in the region of the base portion of the vibrating arms 3 and 4 with the base portion 2. That is, at the base portion of the vibrating arm 3 with the base portion 2, a first region 10 where compressive stress or tensile stress acts by bending vibration, and when compressive stress acts on the first region 10, tensile stress is generated. And when there is a tensile stress acting on the first region 10, there is a second region 11 that is in a relationship in which a compressive stress acts. In these first region 10 and second region 11, When compressive stress is applied, the temperature increases, and when tensile stress is applied, the temperature decreases.
Similarly, at the base portion of the vibrating arm 4 with the base portion 2, when the compressive stress acts on the first region 12 where compressive stress or tensile stress acts due to bending vibration, and the first region 12 When the tensile stress acts and the tensile stress acts on the first region 12, there is a second region 13 in which the compressive stress acts, and in the first region 12 and the second region 13 The temperature rises when compressive stress is applied, and decreases when tensile stress is applied.

Due to the temperature gradient generated in this way, heat conduction is performed between the first regions 10 and 12 and the second regions 11 and 13 inside the base portion of the vibrating arms 3 and 4 with the base 2. appear. The temperature gradient is generated in the opposite direction corresponding to the bending vibration of each of the vibrating arms 3 and 4, and the heat conduction is also reversed in the corresponding direction. Due to this heat conduction, a part of the vibration energy of the vibrating arms 3 and 4 is always lost as a thermoelastic loss during vibration. As a result, the Q value of the tuning fork type crystal vibrating piece 1 is lowered and the vibration characteristics are unstable. Thus, it becomes difficult to achieve desired performance.
In the tuning-fork type crystal vibrating piece 1 of Patent Document 3, heat transfer from the compression side to the pulling side is prevented by the grooves or holes 6 and 7 provided on the center lines of the respective vibrating arms 3 and 4.
It is possible to prevent or reduce a decrease in Q value due to thermoelastic loss. In particular,
By bypassing the flexural vibration body along the grooves or holes 6 and 7 provided in the vibrating arms 3 and 4, the heat conduction path becomes long and the thermal relaxation time τ is extended, so 1 / (2πτ) Is the groove or hole 6 as shown by the thermal relaxation frequency f ₁₀ of the curve F ₁ shown in FIG.
, 7 is shifted to the left side in the figure as compared with the curve F of the conventional tuning-fork type bending vibration piece and its thermal relaxation frequency f ₀ .

JP 2002-261575 A Japanese Patent Laid-Open No. 2004-260718 Actual Application No. Sho 63-110151

C. Zener and two others, “Internal Friction in Solids III. Experimental Demonstration of Thermoelastic Internal Friction”, PHYSICAL REVIEW, January 1, 1938, Volume 53, p.10-101

However, in the tuning fork type crystal vibrating piece 1 described in Patent Document 3, as miniaturization proceeds,
There is a problem that the effect of extending the thermal relaxation time is reduced by the grooves or holes, and the effect of suppressing the decrease in the Q value cannot be obtained sufficiently.

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.

[Application Example 1] The bending vibration piece according to this application example includes a first region where compressive stress or tensile stress is applied by vibration, and when compressive stress is applied to the first region, the tensile stress is applied. When a tensile stress is applied to the first region, the second region is in a relationship in which a compressive stress is applied, and between the first region and the second region, A groove having an opening on at least one of the principal surfaces parallel to the vibration direction of the flexural vibrator;
It has a heat conduction path comprising an embedded member having a higher thermal conductivity than that of the flexural vibrator embedded in the groove.

According to the above configuration, the heat conduction between the first region and the second region is efficiently performed through the heat conduction path having a thermal conductivity higher than that of at least the flexural vibrator, Since the thermal relaxation time required to bring the temperature of the region and the second region into an equilibrium state is shortened, a decrease in the Q value can be suppressed. Therefore, it is possible to provide a small flexural vibration piece that suppresses a decrease in the Q value and has stable vibration characteristics.

Application Example 2 In the bending vibration piece according to the application example described above, the groove is a bottomed groove, and one groove having an opening on the one main surface side of the bending vibration member; It has the other said groove | channel which has an opening part in the position facing the opening part of said one said groove | channel on the other main surface side, It is characterized by the above-mentioned.

According to this configuration, one groove and the other groove having openings on both principal surface sides of the flexural vibration body are formed by etching from both directions, so that one groove having the same etching shape and The other groove is obtained. Therefore, it is possible to provide a flexural vibration piece having a heat conduction path capable of stably conducting heat conduction between the first region and the second region of the flexural vibrator and having a stable Q value.

Application Example 3 In the bending vibration piece according to the application example described above, the groove is a bottomed groove, and a plurality of the grooves are arranged in parallel between the first region and the second region. The openings of the adjacent grooves are alternately arranged on the one main surface side and the other main surface side of the flexural vibrator.

According to this configuration, the heat conduction is performed by linearly passing through the heat conduction path over the entire heat conduction path between the first region and the second region of the bending vibration piece. Therefore, the thermal relaxation time between the first region and the second region can be further shortened, and the decrease in the Q value can be suppressed more effectively.

Application Example 4 In the bending vibration piece according to the application example described above, the embedded member is made of gold (Au
It is characterized by being made of a material having a thermal conductivity higher than the thermal conductivity.

The inventor of the present application has found that according to this configuration, the effect of suppressing the decrease in the Q value can be sufficiently obtained by shortening the thermal relaxation time by the heat conduction path.

Application Example 5 An oscillator according to this application example includes at least the bending vibration piece according to any of the application examples described above and an oscillation circuit that drives the bending vibration piece.

According to this configuration, since the bending vibration piece in which the decrease in the Q value shown in the application example is suppressed is provided, a small oscillator having stable oscillation characteristics can be provided.

(A) is the top view of one main surface side explaining typically the tuning fork type crystal vibrating piece as a bending vibration piece of 1st Embodiment, (b) is the sectional view on the AA line of (a). Figure. (A) is the elements on larger scale which explain typically the connection part of the base of a tuning fork type crystal vibrating piece and each vibrating arm in operation, (b) is a sectional view in the bb line of (a). . An explanatory view showing an example of material applicable as an embedding member of a heat conduction path of a tuning fork type crystal vibrating piece and its thermal conductivity. (A) is the top view of one main surface side explaining typically the tuning fork type crystal vibrating piece of 2nd Embodiment, (b) is the cc sectional view taken on the line of (a). (A) is the top view of one main surface side explaining the modification 1 of a tuning fork type crystal vibrating piece typically, (b) is the dd sectional view taken on the line of (a). (A) is the top view of one main surface side which illustrates typically the modification 2 of a tuning fork type crystal vibrating piece, (b) is the ee sectional view taken on the line of (a). The top view which shows the typical example of the conventional tuning fork type crystal vibrating piece. The diagram showing the relationship between the relaxation frequency and the minimum value of Q value in the bending vibration piece in the bending vibration mode.

Hereinafter, an embodiment in which a bending vibration piece of the present invention is embodied as a tuning fork type quartz vibration piece will be described with reference to the drawings.

(First embodiment)
FIG. 1 schematically illustrates a tuning-fork type quartz vibrating piece as a bending vibrating piece according to the first embodiment. FIG. 1A is a plan view of one main surface side of a tuning-fork type quartz vibrating piece 50. , (B) is (a)
It is an AA sectional view taken on the line.
In FIG. 1A, a tuning-fork type crystal vibrating piece 50 according to this embodiment includes a base 52 formed by processing a bending vibrator material, and a fork from one end side (upper end side in the figure) of the base 52. It is formed with a so-called tuning fork-shaped outer shape, which is composed of a pair of vibrating arms 53 and 54 extending separately from each other. As the flexural vibrator material, in the present embodiment, a material cut out from a single crystal of crystal is used as in the case of a conventional tuning fork type crystal vibrating piece. For example, from a so-called Z-cut quartz thin plate, the Y axis of the quartz crystal axis is in the longitudinal direction of the vibrating arms 53 and 54, and the X axis is in the width direction thereof.
The Z axis is formed so as to be oriented in the vertical direction of the front and back main surfaces of the resonator element.

Note that a configuration using a piezoelectric substrate other than the above-described quartz may be used as the bending vibrator material. For example, aluminum nitride (AlN), lithium niobate (LiNbO ₃ ), lithium tantalate (LiTaO ₃ ), lead zirconate titanate (PZT), lithium tetraborate (L
i ₂ B ₄ O ₇ ) or other oxide substrates, or glass substrates with aluminum nitride or tantalum pentoxide (
A piezoelectric substrate constructed by laminating thin film piezoelectric materials such as Ta ₂ O ₅ ) can be used.
In addition to the piezoelectric substrate, the bending vibration piece can be formed of, for example, a silicon semiconductor material.
However, the resonance frequency of the bending vibration piece is proportional to the square root of the value obtained by dividing the Young's modulus of the bending vibration material by the mass density, and the smaller the value obtained by dividing the Young's modulus by the mass density, the smaller the bending vibration piece. It is advantageous. Therefore, a flexural vibration piece made of crystal like the tuning fork type crystal vibration piece 50 of the present embodiment can reduce the square root of the value obtained by dividing the Young's modulus by the mass density as compared with a silicon semiconductor material or the like. In addition, since it has excellent frequency-temperature characteristics, it is particularly preferable as a material used for the tuning-fork type crystal vibrating piece 50 as the bending vibrating piece of the present invention.

Excitation electrodes 36A and 37A are formed on one main surface of the vibrating arms 53 and 54, respectively. Further, external connection electrodes 76 and 77 for connection to the outside are provided in the vicinity of the other end side different from the one end side where the vibrating arms 53 and 54 of the base 52 are extended. These external connection electrodes 76 and 7
7 correspond to the excitation electrodes 36A and 37A, respectively, and the corresponding electrodes are respectively
The tuning fork-type crystal vibrating piece 50 is connected to a main surface and a side surface of the tuning-fork type crystal vibrating piece 50 by a routing wiring (not shown) provided.

Similarly, excitation electrodes 36B and 37B (see FIG. 1B) as opposed electrodes of the excitation electrodes 36A and 37A in the respective vibration arms 53 and 54 are provided on the other main surface of the respective vibration arms 53 and 54. Each is provided. Here, the excitation electrodes 36A and 36B of the vibrating arm 53 are at the same potential,
The excitation electrodes 37A and 37B of the vibrating arm 54 are at the same potential. The excitation electrodes 36A and 36B and the excitation electrodes 37A and 37B of the vibrating arms 53 and 54 have different potentials. Excitation electrode 36B. 37
B is connected to the corresponding excitation electrodes 36A and 37A, external connection electrodes 76 and 77, and the like by lead wires (not shown) provided by being routed to the main surface and side surfaces of the tuning-fork type crystal vibrating piece 50. Yes.
In addition, although illustration was abbreviate | omitted for convenience in explaining the characteristics of the tuning fork type crystal vibrating piece 50 of the present embodiment in an easy-to-understand manner, both main surfaces on which the excitation electrodes 36A, 36B, 37A, and 37B of the vibrating arms 53 and 54 are formed and Exciting electrodes 36A and 36B of the respective vibrating arms 53 and 54 are provided on both side surfaces orthogonal to each other.
Alternatively, excitation electrodes having the same potential as the excitation electrodes 37A and 37B are formed.

Conventionally, the above-described electrodes and wirings are formed by etching a quartz crystal to form the outer shape of the tuning-fork type crystal vibrating piece 50, and then depositing, for example, nickel (Ni) or chromium (Cr) on the base layer. An electrode layer made of, for example, gold (Au) can be formed by sputtering and then patterned by photolithography.

Further, on one main surface side of each vibrating arm 53, 54, a region including the vicinity of the base of each vibrating arm 53, 54 with the base 52 is provided along the longitudinal direction of each vibrating arm 53, 54. A heat conduction path comprising a single straight bottomed groove 56a, 57a and embedded members 56b, 57b having a higher thermal conductivity than at least a crystal as a flexural vibrator embedded in each of the grooves 56a, 57a. 56 and 57 are formed. In the present embodiment, gold (Au) is used for the embedded members 56b and 57b.
Similarly, as shown in FIG. 1B, on the other main surface side of each vibrating arm 53, 54, an opening is provided at a position facing the grooves 56a, 57a on the one main surface side. Bottomed groove 66a
, 67a and heat conduction paths 66, 67 made of gold embedded members 66b, 67b embedded in the grooves 66a, 67a.

It should be noted that the tuning-fork type crystal resonator element 50 has a tuning-fork type outer shape, grooves 56a and 57a of heat conduction paths 56 and 57 having openings on one main surface side of the vibrating arms 53 and 54, and the other main surface. The grooves 66a and 67a of the heat conduction paths 66 and 67 having openings on the side can be precisely formed by wet etching or dry etching a quartz crystal substrate such as a quartz wafer with a hydrofluoric acid solution or the like. it can. In the present embodiment, a pair of heat conduction paths 56 and 66 or grooves 5 of the heat conduction paths 57 and 67 are provided for each vibration arm having openings on both principal surface sides of the vibration arms 53 and 54.
Since the grooves 6a and 66a or the grooves 57a and 67a are formed by etching from both directions, the grooves 56a and 66a and the grooves 57a and 67a having the same etching shape are obtained. As a result, the heat conduction paths 56 and 66 and the heat conduction paths 57 and 67 for the respective vibrating arms 53 and 54 can be stably conducted as described later, so that the Q value of the tuning-fork type crystal vibrating piece 50 can be stabilized. Has an effect on

The embedded members 56b, 57b, 66b, and 67b of the heat conduction paths 56, 57, 66, and 67, which are particularly important in the configuration of the tuning fork type crystal vibrating piece 50, have a thermal conductivity that is at least higher than that of quartz as a flexural vibrator material. For example, the material shown in FIG. 3 is preferably used. In particular, the embedded members 56b, 57b, 66b, 6 among the materials shown in FIG.
7b, heat conduction paths 56, 57, 6 using a material having a thermal conductivity equal to or higher than that of gold.
The inventors of the present application have found that when 6,67 is provided, thermoelastic loss, which will be described later, is suppressed, and a decrease in Q value can be effectively suppressed. That is, in FIG. 3, the heat conduction paths 56, 57, 66
, 67 embedded materials 56b, 57b, 66b, 67b include gold, copper (
In the case of Cu), silver (Ag), or non-metal, diamond (C) is desirable because it contributes significantly to improving the Q value.

In FIG. 1, when a driving voltage is applied to the tuning fork type quartz vibrating piece 50 from the oscillation circuit (not shown) as excitation means connected to the outside to the excitation electrodes 36A and 36B and the excitation electrodes 37A and 37B, the vibrating arm 53 , 54 bend and vibrate in the horizontal direction, as shown by arrows G in the figure, in directions toward or away from each other. Due to this bending vibration, compressive stress and tensile stress are generated in the region of the base portion in the vibration direction of each vibrating arm 53, 54 at the connecting portion between the base 52 and each vibrating arm 53, 54. The thermal behavior of the connecting portion between the base 52 and the vibrating arms 53 and 54 during operation of the tuning fork type crystal vibrating piece 50 will be described in detail with reference to the drawings. FIG. 2 schematically illustrates a connecting portion between the base 52 and each vibrating arm during the operation of the tuning fork type crystal vibrating piece 50.
) Is a partially enlarged plan view, and (b) is a cross-sectional view taken along line bb of (a).

As shown in FIG. 2A, in the vicinity of the base of the vibrating arms 53 and 54 and the base 52 of the vibrating fork-type quartz vibrating piece, the first region 110 and the second region in the drawing of the vibrating arm 53 are shown. A compressive stress and a tensile stress are generated in 111, and similarly, a compressive stress and a tensile stress are also generated in the region of the connecting portion with the base 52 of the vibrating arm 54. That is, when the free end of the vibrating arm 53 is bent and vibrated in a direction in which the vibrating arm 53 approaches the vibrating arm 54, a tensile stress acts on the first region 110 of the vibrating arm 53 and the temperature decreases, and the second region 111 has The temperature rises due to the compression stress. Conversely, vibrating arm 5
3 is bent in a direction away from the vibrating arm 54, the first region 110 is subjected to compressive stress to increase the temperature, and the second region 111 is subjected to tensile stress to decrease the temperature. To do.

Similarly, when the free end of the vibrating arm 54 is bent and vibrated in a direction in which the vibrating arm 54 approaches the vibrating arm 53, a compressive stress acts on the first region 112 of the vibrating arm 54 and the temperature rises. In the case of tensile stress, the temperature drops. Conversely, when the free end side of the vibrating arm 54 is bent in a direction away from the vibrating arm 53, a tensile stress acts on the first region 112 and the temperature drops, and a compressive stress acts on the second region 113. Temperature rises.
As described above, a temperature gradient is generated between the portion where the compressive stress is applied and the portion where the tensile stress is applied inside the connecting portion of each of the vibrating arms 53 and 54 with the base portion 52. The direction is reversed depending on the direction of vibration of the arms 53 and 54.

Due to this temperature gradient, heat is transferred from the compression part to the tension (elongation) part, that is,
It is transmitted from the high temperature side to the low temperature side. In the tuning fork type crystal vibrating piece 50 of the present embodiment, the heat transfer from the compression side portion to the extension side portion is caused by the excitation electrodes 36A, 3 of the vibrating arms 53, 54.
6B and a part of the excitation electrodes 37A and 37B are used as a heat conduction path.

The vibration arm 53 side shown in FIG. 2B will be described in detail as an example. FIG. 2 (b) is similar to FIG. 2 (a).
2 is a cross-sectional view taken along line bb when the vibrating arm 53 is bent in a direction away from the vibrating arm 54, and the first region 110 in FIG. Region 1
The case where 11 becomes an expansion | extension side is illustrated. In the figure, the temperature rise is indicated by + and the temperature drop is indicated by-. The temperature on the compression side increases and the temperature on the expansion side decreases. Due to this temperature gradient, heat is transferred from the compression side (+) portion to the expansion side (−) through the heat conduction paths 56 and 66 of the vibrating arm 53.

In the present embodiment, a heat conduction path using gold having a much higher thermal conductivity than the crystal 51 as the embedded members 56b and 66b in the heat transfer path between the compression side (+) portion and the expansion side (−). 5
6,66 are provided. As a result, heat transfer between the compression side (+) portion and the expansion side (−) is efficiently performed via the heat conduction paths 56 and 66, and between the compression side (+) and the expansion side (−). Thus, the relaxation time τ ₁ until the temperature reaches an equilibrium state is shorter than the relaxation time τ _{0 of the} conventional tuning fork type crystal vibrating piece in which the heat conduction paths 56 and 66 are not provided. That is, in the thermal relaxation frequency f ₂₀ = 1 / tuning-fork type crystal vibrating piece 50 of this embodiment (2πτ _1), τ ₁ <because it is tau _0, thermal relaxation frequency f ₀ of the tuning fork type crystal vibrating piece of the conventional structure The thermal relaxation frequency f ₂₀ of this embodiment is higher than the thermal relaxation frequency of = 1 / (2πτ ₀ ).

Looking at the relationship between the mechanical vibration frequency (resonance frequency) and the Q value of the vibrating arm in FIG.
Since the shape of the curve F itself does not change, the curve F changes to the curve F as the thermal relaxation frequency increases.
_This means that the frequency has been shifted to the position _{2 in} the direction of increasing frequency (rightward on the page). Therefore,
When the mechanical vibration frequency (resonance frequency) of the vibrating arm is fr, fr is the thermal relaxation frequency f _0.
In the following range, that is, in the range satisfying 1 ≧ fr / f ₀ , the Q value in the curve F ₂ is always higher than the curve F of the tuning-fork type crystal vibrating piece having the conventional structure. In addition, in the curve F ₂ , a frequency band lower than the frequency of the intersection of the curve F and the curve F ₂ , that is, 1> fr / (f ₀ + (f ₂₀ −f ₀ ) / 3).
Even within the range satisfying the above, the Q value in the curve F of the tuning-fork type crystal vibrating piece having the conventional structure is higher. As described above, the tuning fork type crystal vibrating piece 50 of the present embodiment has the heat conduction paths 56 and 66 between the first regions 110 and 112 and the second regions 111 and 113 of the respective vibrating arms 53 and 54. By providing, it is possible to improve the Q value and realize high performance.

Further, in the present embodiment, grooves 56a, 57a, 66a opened on both principal surface sides parallel to the bending vibration direction of the vibrating arms 53, 54 in the vicinity of the base portion of the vibrating arms 53, 54 with the base 52.
, 67a, and embedded members 56b, 57b in the grooves 56a, 57a, 66a, 67a.
, 66b, 67b are embedded to form heat conduction paths 56, 57, 66, 67. Grooves 56a, 57a provided in the vicinity of the bases of the resonating arms 53, 54 and the base portion 52,
66a and 67a reduce the leakage of vibration from the base 52 when the vibration of the vibrating arms 53 and 54 includes a vertical component, thereby reducing the Q value by the heat conduction paths 56, 57, 66, and 67. In addition to this improvement effect, the confinement effect of the heat conduction path vibration energy is enhanced to suppress the CI value, and the effect of preventing variation in the CI value between the tuning fork type crystal vibrating pieces is achieved.
In addition, since each of the grooves 56a, 57a, 66a, and 67a on each main surface of each vibrating arm 53 and 54 has one opening, the opening can be enlarged, and therefore the tuning-fork type crystal vibrating piece 50 can be downsized. It is relatively easy to process even if it is advanced.
Further, the grooves 56a, 57a, 66a, 6 of the heat conduction paths 56, 57, 66, 67 of the present embodiment.
Since the groove 7a has a bottom, the heat conduction paths 56, 57, and the like can be obtained by, for example, a method in which an embedding member such as gold in the grooves 56a, 57a, 66a, and 67a is melted and poured.
66 and 67 can be formed relatively easily.

(Second Embodiment)
In the first embodiment, the grooves 56a opened on both main surfaces of the vibrating arms 53 and 54, respectively.
57a, 66a, 67a and the embedded member 56 in the grooves 56a, 57a, 66a, 67a
The heat conduction paths 56, 57, 66, and 67 including b, 57b, 66b, and 67b were formed. That is, the heat conduction path between the first region 110 and the second region 111 of the vibrating arm 53 includes a pair of heat conduction paths 56 and 66 and the first region 112 and the second region of the vibrating arm 54. A pair of heat conduction paths 57 and 67 are interposed in the heat conduction path to 113. The configuration is not limited to this, and a plurality of heat conduction paths may be interposed between the first region and the second region for each vibrating arm (flexural vibrator).
FIG. 4 schematically illustrates a tuning-fork type crystal vibrating piece in which two heat conduction paths are provided between the first region and the second region of the flexural vibration body. Plan view of surface side, (b) is (a)
FIG. In FIG. 4, the same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

In the tuning fork type crystal vibrating piece 150 of the second embodiment shown in FIG. 4A, an opening is formed on one main surface side of the vibrating arm 53 in a region including the vicinity of the base of the vibrating arm 53 with the base 52. A straight bottomed groove 156a provided along the longitudinal direction and an opening on the other main surface side of the resonating arm 53, and a linear provided groove arranged in parallel with the groove 156a. The bottom groove 166a and the embedded member 1 made of a material having high thermal conductivity such as gold embedded in each of the grooves 156a and 166a
Thermal conduction paths 156 and 166 including 56b and 166b are formed (see also FIG. 4B).

Similarly, in a region including the vicinity of the base with the base 52 of the vibrating arm 54, a linear bottomed groove 157a having an opening on one main surface side of the vibrating arm 54 and provided along the longitudinal direction. And a straight bottomed groove 167a having an opening on the other main surface side of the vibrating arm 54 and arranged in parallel to the groove 157a, and an embedded member 157b embedded in each of the grooves 157a and 167a , 16
Heat conduction paths 157 and 167 composed of 7b are formed.

According to this configuration, the vibrating arms 53 and 54 of the tuning fork type crystal vibrating piece 50 of the first embodiment are used.
In addition to the heat conduction paths 56, 66, 57, and 67, the flexural vibrator is used as a heat conduction path between the first areas 110 and 112 and the second areas 111 and 113 (see FIG. 2A). Crystal 51 as material
(For example, refer to FIG. 2B for explaining the vibrating arm 53)
The heat conduction linearly passes through the heat conduction paths 156, 166, 157, and 167 over the entire heat conduction path between the first region and the second region of each vibrating arm 53 and 54, respectively. It can be set as the structure performed. Therefore, since the heat conduction efficiency at the time of thermal relaxation between the first region and the second region of each vibrating arm can be further improved, the decrease in the Q value can be more effectively suppressed.

The tuning-fork type crystal vibrating piece as the bending vibrating piece described in the above embodiment can also be implemented as the following modifications.

(Modification 1)
In the tuning fork type crystal vibrating piece 150 of the second embodiment, two heat conduction paths 156 and 166 and two heat conduction paths 157 and 167 are provided for each vibrating arm 53 and 54. Not limited to this, three or more heat conduction paths may be arranged in parallel.
FIGS. 5A and 5B schematically illustrate a tuning-fork type crystal vibrating piece according to the first modification. FIG. 5A is a plan view of one main surface side, and FIG. 5B is a cross-sectional view taken along the line dd in FIG. FIG.

In the tuning-fork type crystal vibrating piece 250 of this modification shown in FIG. 5A, the base 52 of the vibrating arm 53 is used.
In the region including the vicinity of the root of the groove, there are two linear bottomed grooves 256a and 276a provided in parallel along the longitudinal direction having an opening on one main surface side of the vibrating arm 53, and Groove 256
a, embedded member 256b made of a material having high thermal conductivity such as gold embedded in 276a,
276b are formed, and two heat conduction paths 2 are formed.
56 and 257 have an opening on the other main surface side of the vibrating arm 53 and have the grooves 256a,
A heat conduction path 266 is formed which includes a straight bottomed groove 266a provided in parallel with 276a and an embedded member 266b embedded in the groove 266a (see also FIG. 5B). .

Similarly, in a region including the vicinity of the base of the vibrating arm 54 with the base 52, there is an opening on one main surface side of the vibrating arm 54 and two linear objects provided in parallel along the longitudinal direction. Bottom groove 257a
, 277a and embedded members 257b, 27 embedded in the grooves 257a, 277a.
7b is formed, and two heat conduction paths 257 are formed.
And 277 have an opening on the other main surface side of the vibrating arm 54 and have the grooves 257a, 27.
A heat conduction path 267 is formed which includes a straight bottomed groove 267a provided in parallel with 7a and an embedded member 267b embedded in the groove 267a.

According to this configuration, heat conduction is performed in the heat conduction paths 256, 266, 276, or the heat conduction path 25 over the entire heat conduction path between the first region and the second region of each of the vibrating arms 53 and 54.
7, 267, and 277 are linearly passed, and the heat conduction efficiency at the time of thermal relaxation between the first region and the second region of each vibrating arm is further improved, so that the Q value can be reduced more effectively. Can be suppressed.

(Modification 2)
In the said embodiment and the modification 1, the heat conduction path provided in the base vicinity with the base 52 of the vibrating arms 53 and 54 was formed by embedding an embedding member in the bottomed groove. Not only this,
The heat conduction path may be formed by embedding an embedded member in the through hole.
6A and 6B schematically illustrate a tuning-fork type crystal vibrating piece according to Modification 2. FIG. 6A is a plan view of one main surface side, and FIG. 6B is a cross-sectional view taken along line ee in FIG. FIG.

In the tuning-fork type crystal vibrating piece 350 of this modification shown in FIG. 6A, the base 52 of the vibrating arm 53 is provided.
In the region including the vicinity of the base of the vibration arm 53, a linear through-hole 356a penetrating in the longitudinal direction from one main surface to the other main surface of the vibrating arm 53, and embedded in the through-hole 356a. A heat conduction path 356 is formed which includes an embedded member 356b made of a material having high thermal conductivity such as metal (see also FIG. 6B).

Similarly, in a region including the vicinity of the base with the base 52 of the vibrating arm 54, a linear through hole 357a penetrating in the longitudinal direction from one main surface of the vibrating arm 54 to the other main surface. And an embedded member 357b made of a material having high thermal conductivity such as gold embedded in the through hole 357a.
A heat conduction path 357 is formed.

In this configuration, when forming the through holes 356a and 357a of the respective heat conduction paths 356 and 357, a method of performing wet etching from both directions on both main surfaces, or linear in the depth direction of the through holes 356a and 357a. The cross-sectional shapes of the through holes 356a and 357a can be processed into symmetrical shapes by performing anisotropic etching such as a reactive ion etching method that advances etching. According to this configuration, the heat conduction path 356 including the embedded members 356b and 357b made of a material having high heat conductivity such as gold between the first region and the second region of the vibrating arms 53 and 54. , 357 can be provided large. Therefore, when the thermal relaxation is performed to reduce the temperature difference between the first region and the second region of the vibrating arms 53 and 54 caused by the bending vibration, the Q value can be further lowered by improving the heat conduction efficiency. It can be effectively suppressed.

[Oscillator]
The tuning-fork type crystal vibrating piece 50 as the bending vibrating piece described in the first embodiment and the modification example.
, 150, 250, 350 can be applied to various electronic components other than piezoelectric devices and piezoelectric devices. In particular, the tuning fork type crystal vibrating pieces 50, 150,
An oscillator configured by incorporating at least an oscillation circuit element that oscillates one of the flexural vibration pieces of 250 and 350 with the flexural vibration piece improved in Q value, improved performance, and reduced in size. Can be achieved.

The embodiment of the present invention made by the inventor has been specifically described above, but the present invention is not limited to the above-described embodiment, and various modifications are made without departing from the scope of the present invention. Is possible.

For example, in the embodiment and the modification, the tuning-fork type crystal vibrating piece 50 as the bending vibrating piece,
150, 250, and 350 have been described. The present invention is not limited to this, and the bending vibration piece of the present invention may be a strip-shaped so-called beam-type bending vibration piece, or may be a bending vibration piece having three or more vibrating arms. The same effect as the example can be obtained.

In the embodiment and the modification, the tuning fork type crystal vibrating pieces 50, 150, 250, and 350 made of quartz have been described as an example of the bending vibrating piece. Also good.
The base material of the bending vibration piece is not limited to a piezoelectric substrate made of a piezoelectric material. In addition to the piezoelectric drive type using a piezoelectric substrate, the electrostatic drive type using electrostatic force and the magnetic drive type bending vibration piece using magnetism can also exert the configuration and effects of the present invention. it can.

1, 50, 150, 250, 350... Tuning fork type crystal vibrating piece as a bending vibrating piece, 2, 52
... Base, 3, 4, 53, 54 ... Vibrating arm, 6, 7 ... Hole, 10, 12, 110, 112 ... First
Area 11, 11, 111, 113 ... second area 36A, 36B, 37A, 37B ...
Excitation electrode, 51... Crystal as bending vibration material, 56, 57, 66, 67, 156, 15
7,166,167,256,257,266,267,276,277,356,35
7 ... heat conduction path, 56a, 57a, 66a, 67a, 156a, 157a, 166a, 16
7a, 256a, 257a, 266a, 267a, 276a, 277a... Groove, 56b, 5
7b, 66b, 67b, 156b, 157b, 166b, 167b, 256b, 257b
, 266b, 267b, 276b, 277b, 356b, 357b ... embedded member, 35
6a, 357a ... through holes.

Claims (5)

A first region where compressive stress or tensile stress is applied by vibration, and a compressive stress is applied when compressive stress is applied to the first region, and a compressive stress is applied when tensile stress is applied to the first region. A second region in an acting relationship, and a flexural vibrator having
Between the first region and the second region, a groove having an opening on at least one of the principal surfaces parallel to the vibration direction of the flexural vibrator, and embedded in the groove A bending vibration piece having a heat conduction path comprising an embedded member having a higher thermal conductivity than the bent vibration body. The bending vibration piece according to claim 1,
The groove is a bottomed groove, and the one groove having an opening on the one main surface side of the flexural vibrator, and the opening of the one groove on the other main surface side, A flexural vibration piece comprising: the other groove having an opening at an opposing position. The bending vibration piece according to claim 1,
The groove is a bottomed groove, and a plurality of the grooves are arranged in parallel between the first region and the second region, and the opening of the adjacent groove is the bending vibrator. The bending vibration piece is arranged alternately on the one main surface side and the other main surface side. In the bending vibration piece according to any one of claims 1 to 3,
The bending vibration piece, wherein the embedded member is made of a material having a thermal conductivity higher than that of gold (Au). An oscillator comprising at least the bending vibration piece according to any one of claims 1 to 4 and an oscillation circuit for driving the bending vibration piece.

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