JP2014116977A - Vibration piece and vibrator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a piezoelectric vibrator in which the CI value does not deteriorate, even if the etching depth of a mesa is made larger than conventional, with excellent productivity.SOLUTION: A piezoelectric vibration piece 12 is constituted of a thick part 14 (vibration part) and a thin part 16 (peripheral part), a protrusion 18, and an electrode film (excitation electrode 22). When the long side dimension of a piezoelectric element plate is X, the thickness dimension of the thick part is t, the long side dimension of the thick part is Mx, the long side dimension of the excitation electrode is Ex, and the wavelength in flexural displacement is λ, the dimension Dx of the protrusion and the dimension Sx from the thick part to the protrusion satisfy a predetermined relationship.

Description

  The present invention relates to a piezoelectric vibrator, and more particularly to a piezoelectric vibrator on which a mesa-type piezoelectric vibrating piece having a vibrating portion with a thickness dimension larger than that of a peripheral portion is mounted.

  A mesa-type piezoelectric vibrating piece is known as a form of a piezoelectric vibrating piece that is capable of confining vibration energy and has excellent productivity due to a form similar to a bevel-type or convex-type piezoelectric vibrating piece. Yes.

  However, in the mesa-type piezoelectric vibrating piece having a step at the boundary between the vibrating portion and the peripheral portion, spurious such as bending vibration that is unnecessary vibration may increase due to the effect of the step. Under such a background, Patent Document 1 discloses that spurious can be suppressed by optimizing the position of a stepped portion formed between a vibrating portion and a peripheral portion.

  Patent Document 2 discloses a technique for suppressing spurious and reducing the CI value by optimizing the size (depth) of the step portion in addition to the position of the step portion. Patent Document 3 discloses that the effect of suppressing spurious is enhanced by extending the formation position of the excitation electrode to the peripheral part where the excitation electrode is thin and setting the end of the excitation electrode at the position of the antinode of unnecessary vibration.

  As described above, in the piezoelectric vibrator using the mesa-type piezoelectric vibrating piece, the position of the edge of the mesa, that is, the thick part and the position of the edge of the excitation electrode are optimized in relation to the displacement of the bending vibration. Accordingly, various proposals have been made to suppress bending vibration.

  By the way, as disclosed in Patent Document 2, the CI value can be reduced as the ratio of the moat amount in the thick-walled portion is deepened. However, when the ratio of the moat amount exceeds a certain range, the CI value changes. In some cases, the CI value increases (deteriorates). With respect to such a phenomenon, Patent Document 4 discloses that a mesa portion is formed in multiple stages to secure a moat amount (deepening a step portion) and reduce a CI value.

JP 2006-340023 A JP 2008-263387 A JP 2008-306594 A JP-A-10-308645

  As the above-mentioned patent document shows, the mesa structure can suppress unnecessary waves by specifying the position of the stepped portion. In addition, the CI value of the main vibration can be reduced as the ratio of the moat amount in the step portion is increased. However, when the moat ratio exceeds a certain value, the CI value is deteriorated, that is, the CI value is increased. When the phenomenon occurs and the production error is taken into consideration, there is a fact that the moat amount cannot be increased to the limit value.

Further, in the configuration disclosed in Patent Document 4 in which mesa portions are formed in multiple stages in order to increase the relative moat amount, the CI value can be reduced, but the multi-stage mesa portions are formed. There is a concern that the number of photo processes to increase the productivity and the productivity will extremely deteriorate.
Therefore, an object of the present invention is to provide a piezoelectric vibrator that is excellent in productivity and does not cause the CI value to deteriorate even when the amount of excavation in the mesa portion is larger than in the past.

  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.

の関係を満たし、前記振動部の長手方向の延長線上に、前記振動部の短辺方向に平行に配置された凸部を有し、前記凸部における前記主振動の変位方向の寸法をＤｘとしたとき、

の関係を満たし、前記振動部と前記凸部との間の寸法をＳｘとしたとき、

の関係を満たすことを特徴とする圧電振動子。 [Application Example 1] Piezoelectric element plate having a vibration part having a thickness shear vibration as a main vibration and surrounded by a peripheral part and having a thickness dimension larger than that of the peripheral part, and an excitation electrode disposed on the main surface of the piezoelectric element board, A long side of the vibrating part and a long side of the excitation electrode are both parallel to a long side of the piezoelectric element plate, and a long side dimension of the piezoelectric element plate is X, When the thickness dimension of the vibration part is t, the long side dimension of the vibration part is Mx, the long side dimension of the excitation electrode is Ex, and the wavelength of bending vibration generated in the longitudinal direction of the piezoelectric element plate is λ,

On the extension line in the longitudinal direction of the vibration part, and a dimension of the displacement direction of the main vibration in the convex part is Dx. When

And when the dimension between the vibrating part and the convex part is Sx,

A piezoelectric vibrator characterized by satisfying the relationship:

  According to the piezoelectric vibrator having such a feature, it is possible to obtain a piezoelectric vibrator that is excellent in productivity and does not cause the CI value to deteriorate even when the amount of excavation of the mesa portion is larger than the conventional one. .

の関係を満たすことを特徴とする圧電振動子。 Application Example 2 In the piezoelectric vibrator according to Application Example 1, the excitation electrode extends from the main surface of the vibration part to the peripheral part located between the convex part and the vibration part. And the distance L1 to the edge portion of the excitation electrode extending in the peripheral portion is

A piezoelectric vibrator characterized by satisfying the relationship:

  Even a piezoelectric vibrator having such characteristics can achieve the same effects as those of the piezoelectric vibrator having the above-described characteristics.

  [Application Example 3] The piezoelectric vibrator according to Application Example 1 or Application Example 2, wherein the piezoelectric element plate is a crystal plate, a stepped part between the vibrating part and the peripheral part, and the peripheral part and the convex The step portion with the portion has an inclined surface, and the dimension of the vibrating portion, the dimension from the vibrating portion to the convex portion, and the dimension of the convex portion are determined based on the center of the inclined surface, respectively. Piezoelectric vibrator.

  According to the piezoelectric vibrator having such a feature, even when the piezoelectric vibrating piece is formed by wet etching, a reference for determining dimensions can be obtained.

  Application Example 4 In the piezoelectric vibrator according to any one of Application Examples 1 to 3, the convex portion is provided only on one end side on the longitudinal direction side of the vibration portion. A piezoelectric vibrator characterized by that.

  Even when the piezoelectric vibrating piece having such characteristics is mounted, the same effect as that of the piezoelectric vibrator having the above characteristics can be obtained.

  [Application Example 5] The piezoelectric vibrator according to any one of Application Examples 1 to 3, wherein a short side dimension of the convex part is matched with a short side dimension of the vibration part. Piezoelectric vibrator.

  By having such a feature, it is possible to suppress bending vibration that occurs at least in the range of the vibration part serving as the vibration part.

  [Application Example 6] In the piezoelectric vibrator according to any one of Application Examples 1 to 5, the height of the vibration part and the height of the convex part with respect to the peripheral part are set to be the same. A piezoelectric vibrator characterized by that.

  By having such a feature, the convex portion and the vibrating portion can be formed in a single etching step. Therefore, the productivity of the piezoelectric vibrating piece can be increased, and the productivity of the piezoelectric vibrator itself can be improved.

It is a figure which shows the structure of the piezoelectric vibrator which concerns on 1st Embodiment. It is a figure which defines each part dimension in the piezoelectric vibrating piece of 1st Embodiment. It is a figure which shows the relationship between each part of a piezoelectric vibrating piece, and the displacement of bending vibration. It is a graph which shows the relationship between the change of the ratio of a mesa moat amount, and the change of CI value. It is a figure for demonstrating deterioration of CI value accompanying the change of the dimension between a vibration part and a convex part, and its allowable range. It is a figure which shows the structure of the piezoelectric vibrator which concerns on 2nd Embodiment. It is a figure which defines each part dimension in the piezoelectric vibrating piece of 2nd Embodiment. It is a graph which shows the simulation for proving the effect in the piezoelectric vibrator which concerns on 2nd Embodiment. It is a figure which shows the structure of the piezoelectric vibrator which concerns on 3rd Embodiment. It is a graph which shows the simulation for proving the effect in the piezoelectric vibrator which concerns on 3rd Embodiment.

  Hereinafter, embodiments of the piezoelectric vibrator of the present invention will be described in detail with reference to the drawings. First, a first embodiment according to a piezoelectric vibrator of the present invention will be described with reference to FIG. 1A is a diagram illustrating a front configuration of the piezoelectric vibrator, and FIG. 1B is a diagram illustrating a planar configuration in a state of being transmitted through a lid.

  The piezoelectric vibrator 10 according to the present embodiment is configured based on the piezoelectric vibrating piece 12 and the package 30. The piezoelectric vibrating piece 12 is configured by a quartz element plate (piezoelectric element plate) that is cut out with a cut angle called AT cut or BT cut and excited by thickness-shear vibration as a main vibration. In the quartz base plate (piezoelectric vibrating piece 12), the side parallel to the X axis of the quartz is the long side, the side parallel to the Z ′ axis of the quartz is the short side, and the thickness of the quartz base plate is Y ′. It shall be parallel to the axis.

  The piezoelectric vibrating reed 12 constituted by such a crystal element plate is constituted by a thick portion (vibrating portion) 14, a thin portion (peripheral portion) 16, a convex portion 18, and an electrode film 20. The thick portion 14 is defined in relation to the thin portion 16, and the thin portion 16 is provided around the thick portion 14. In the present embodiment, as described above, the thick portion 14 having a rectangular plane is stacked on the rectangular flat plate having the long side in the direction parallel to the X axis of the crystal so that the long sides are parallel to each other. The integrated form is composed of a single base plate. The thick portion 14 is provided so as to be convex on both main surfaces of the thin portion 16.

  A convex portion extending in a direction orthogonal to the direction parallel to the long side of the thick portion 14 provided in this way, that is, the direction parallel to the displacement direction of the main vibration in the thick portion 14 (X-axis direction in the figure). 18 is provided. With reference to the surface of the thin portion 16, the thickness of the convex portion 18 in the Y ′ direction has the same height (the amount of moat) as the thickness of the thick portion 14 in the Y ′ axis direction. Further, the extending direction of the convex portion 18 is provided so as to be parallel to the width direction (Z′-axis direction in the drawing) of the thick portion 14. In the present embodiment, the length of the convex portion 18 in the Z′-axis direction is the same as the width of the thick portion 14.

  The electrode film 20 includes an excitation electrode 22, an extraction electrode 24, and an input / output electrode 26. In the present embodiment, the excitation electrode 22 is formed on both the one surface (14a) and the other surface (14b) of the thick portion 14. The form of the excitation electrode 22 is not particularly limited, but in the present embodiment, as shown in FIG. 1B, the excitation electrode 22 has a shape similar to the planar shape of the thick portion 14. The input / output electrode 26 is provided on the other surface of one end (referred to as a base-side end) in the longitudinal direction of the thin portion 16. The extraction electrode 24 electrically connects the excitation electrode 22 formed on one surface and the other surface of the thick portion 14 and the input / output electrode 26 formed on the other surface at the base side end of the thin portion 16. Be routed to connect to.

で示すことができる。なお周波数定数ｋは、水晶素板がＡＴカットである場合には１．６７０（ＭＨｚ・ｍｍ）、ＢＴカットである場合には２．５６０（ＭＨｚ・ｍｍ）とする。そして、電極による周波数低下量を考慮した場合には、数式２が成り立ち、屈曲振動の波長λ（ｍｍ）と、厚肉部１４の板厚ｔ（ｍｍ）との関係を示すことができる。 In the piezoelectric vibrating piece 12 having such a basic configuration, the wavelength λ of the bending vibration, which is an unnecessary wave, is determined by the thickness t (mm) of the thick portion 14 configured as the vibrating portion. Here, the relationship between the plate thickness t (mm) of the thick part 14 and the frequency f (MHz) of the thickness shear vibration that is the main vibration of the piezoelectric vibrating piece 12 is

Can be shown. The frequency constant k is 1.670 (MHz · mm) when the quartz base plate is AT cut, and 2.560 (MHz · mm) when the quartz base plate is BT cut. Then, when the amount of frequency decrease due to the electrode is taken into account, Equation 2 is established, and the relationship between the wavelength λ (mm) of the bending vibration and the plate thickness t (mm) of the thick portion 14 can be shown.

  As described in Patent Documents 1 and 3, when both the end portion of the thick portion 14 and the end portion of the excitation electrode 22 are located at the antinodes of the bending vibration waveform (bending displacement), the bending vibration is generated. It is known that ingredients are suppressed. Therefore, when the dimensions for aligning the edge portion of the thick portion 14 and the edge portion of the excitation electrode 22 with the position of the antinode of the bending displacement are expressed in relation to the waveform λ of the bending vibration, Equation 3 is obtained. 2, the long side dimension of the excitation electrode 22 is Ex (mm), and the long side dimension of the thick portion 14 is Mx (mm).

  In the case of the relationship example represented by Expression 3, it is assumed that the center position of the thick portion 14 and the center position of the excitation electrode 22 are matched.

  Further, the relationship between the long side dimension Mx (mm) of the thick portion and the wavelength λ (mm) can be expressed by Equation 4.

  The above relational expression assumes that the long side dimension X (mm) of the quartz base plate is sufficiently larger than the thickness dimension t (mm) of the thick portion 14. Specifically, the relationship of Equation 5 may be satisfied.

  According to the piezoelectric vibrating piece 12 that satisfies the above relationship, the bending vibration component is suppressed. However, it is known that if only such a relationship is satisfied, the CI value is extremely deteriorated when the amount of excavation of the thick portion 14 exceeds a certain ratio.

  Therefore, in this embodiment, as shown in FIGS. 2 and 3, the convex portion 18 is provided on the thin portion 16, and the edge portion of the convex portion 18 is bent in the relationship between the convex portion 18 and bending vibration. I came up with the relationship to match the displacement belly.

  And in order to satisfy such a relationship, the X-axis direction dimension Dx (mm) in the convex part 18 and the dimension Sx (mm) from the edge part of the thick part 14 to the edge part of the convex part 18 are set. What is necessary is to obtain | require by the relationship with the wavelength (lambda) of bending displacement, and satisfy | fill this.

とすることができる。また、圧電振動片１２における厚肉部１４の端縁部分から凸部１８の端縁部分までの寸法Ｓｘ（ｍｍ）は、

とすることができる。 Based on the above, the X-axis direction dimension Dx (mm) of the convex portion 18 is as follows.

It can be. Further, the dimension Sx (mm) from the edge portion of the thick portion 14 to the edge portion of the convex portion 18 in the piezoelectric vibrating piece 12 is:

It can be.

  By satisfying all of these relationships, the end portion of the thick portion 14, the end portion of the excitation electrode 22, and the end portion of the convex portion 18 are all located on the antinodes of the bending displacement, and bending vibration is generated. Suppression can be achieved.

  Further, by adopting such a configuration, it is possible to suppress the deterioration of the CI value when the height (the amount of moat) of the thick portion 14 is increased. FIG. 4 shows a mesa-type piezoelectric vibrator (prior art) in which the convex portion is not provided and the edge portion of the thick wall portion and the edge portion of the excitation electrode coincide with the antinodes of the bending displacement, and this embodiment (the invention of the present application). The change in the CI value with respect to the difference in the ratio of the moat amount (Md) in the mesa piezoelectric vibrator having the convex portion according to FIG. When observing FIG. 4, when comparing the conventional structure of the same Md with the present invention, the CI value tends to decrease due to the provision of the convex portion, and the length of the long side of the piezoelectric element plate is X = 1. . 375 (mm) was found to be most effective.

  As can be seen from FIG. 4, in the piezoelectric vibrator according to the prior art, when Md is increased from 15% (ratio to the thickness dimension t) to 20% in all sizes (X dimension), the CI value is deteriorated. Can be confirmed. On the other hand, in the piezoelectric vibrating piece 12 according to the present invention, when the value of Md increases from 15% to 20%, there is almost no deterioration compared to the CI value at Md = 15% (X = 1.375 mm). In the case of = 1.385 (mm), it is observed that the CI value is slightly deteriorated compared to Md = 15%, but there is a condition that the CI value is further reduced (when X = 1.365 mm). I understand that.

  As described above, according to the piezoelectric vibrator 10 according to this embodiment that employs the piezoelectric vibrating piece 12 that satisfies the above-described configuration, the CI value can be obtained even when the ratio (Md) of the thick portion 14 is increased. Can be prevented. For this reason, it is possible to mass-produce piezoelectric vibrators having a moat ratio capable of obtaining a desired CI value without considering the deterioration of the CI value due to over-etching.

  Here, when the crystal base plate is formed by wet etching (hereinafter simply referred to as etching), the cross section may be inclined due to anisotropy in the crystal direction. In the case of the AT-cut quartz base plate used in the present embodiment, as shown in FIG. 3, the step portion between the thick portion 14 and the thin portion 16 becomes an inclined surface. If the intermediate point of the inclined surface generated by the direction is defined as the end edge portion and this portion is configured to coincide with the antinodes of the bending displacement, a piezoelectric vibrator having good CI characteristics can be realized.

  Further, in the piezoelectric vibrating piece 12 according to the present embodiment, the positional relationship between the thick portion 14 and the convex portion 18 can have a tolerance of about ± 0.1λ. As can be seen from the evaluation results of the CI characteristics shown in FIG. 5, when the interval between the thick portion 14 and the convex portion 18 is shifted, the CI value is deteriorated. According to the above, it has been found that the CI value deteriorates by about 10Ω every time the thickness portion 14 and the convex portion 18 change by 10 μm. The piezoelectric vibrator illustrated in FIG. 5A has a frequency f of 24 (MHz), an X dimension of 1.375 (mm), Md of 20%, and a bending vibration wavelength λ of about 107 ( μm). In FIG. 5A, the reference graph shows that the value between the mesa end and the convex indicating the dimension from the thick portion 14 to the convex portion 18 is 2 of the value of the convex width Dx indicating the width of the convex portion 18. The graph on the right closest to double.

  With reference to the graph on the right side of FIG. 5A, the CI value when the Sx value (the value between the mesa and the convexity) is shifted and changed by 10 μm, and the CI value of the piezoelectric vibrator in the conventional structure (see FIG. 4). Since the CI value was deteriorated when the amount of deviation was 20 (μm), it was found that both of the deviations 10 (μm) were in a substantially allowable range.

  Further, in the piezoelectric vibrator having the frequency f of 26 (MHz), as shown in FIG. 5B, even when the position of the convex portion is changed by 10 (μm), the CI value is deteriorated. I can't. In FIG. 5B, the middle graph in which the value between the mesa-convex and the value of the convex width are matched is used as a reference. Further, the wavelength λ of the bending vibration is about 98 (μm).

と示すことができる。このことより、数式７においては、許容差を波長λとの関係によって示すこととした。 Based on these simulation evaluations, in the piezoelectric vibrator according to this embodiment, the value of Sx hardly affects the deterioration of the CI value even when an error of about ± 10 (μm) occurs. It is thought that there is not. Therefore, in this embodiment, the tolerance of Sx is set to ± 10 (μm). The wavelength λ of the bending displacement in the piezoelectric vibrator with f = 24 (MHz) is about 107 (μm), and the wavelength λ of the bending displacement in the piezoelectric vibrator with f = 26 (MHz) is about 98 (μm). As a result, assuming that the wavelength of bending displacement in these piezoelectric vibrators is about 100 (μm),

Can be shown. Therefore, in Equation 7, the tolerance is indicated by the relationship with the wavelength λ.

  Next, the package constituting the piezoelectric vibrator includes a package base and a lid. The package base 32 shown in FIG. 1 has a rectangular box shape, and includes an internal mounting terminal 38 on the inner bottom surface and an external terminal 40 on the outer bottom surface. The internal mounting terminal 38 and the external mounting terminal 40 are electrically connected by a wiring pattern (not shown).

  The piezoelectric vibrating reed 12 described above is mounted on the package base 32 via a joining member 42 such as a conductive adhesive. In the mounting process, a bonding member is applied to the internal mounting terminals 38 in the package base 32, and the piezoelectric vibrating reed 12 is mounted so that the input / output electrodes are positioned above the applied bonding member 42.

  As shown in FIG. 1, when a box-shaped package base 32 is adopted, a flat plate so-called lid is adopted as the lid 34. The lid 34 is joined to the package base 32 via a seam ring 36 as a brazing material.

The piezoelectric vibrator 10 having such a configuration is manufactured by the following process.
First, a corrosion-resistant film is formed on an AT-cut or BT-cut quartz base plate. Thereafter, a resist film is formed so as to cover the corrosion-resistant film, and a patterning process for opening a portion excluding the thick portion 14 and the convex portion 18 is performed on the resist film. The corrosion resistant film is etched using the patterned resist film as a mask, and then the quartz base plate is etched using the resist film and the corrosion resistant film as a mask.

  In addition, since the amount of crystal trenches by etching and the angle of the crystal plane caused by the anisotropy of the crystal direction are known, the patterning of the resist film at the time of etching is performed in consideration of this. .

  The resist film and the corrosion-resistant film are peeled off from the crystal blank after the outer shape formation by etching, and a metal film for forming the excitation electrode 22, the input / output electrode 26, and the extraction electrode 24 is formed. The metal film may be formed by means such as vapor deposition or sputtering.

  After the metal film is formed, the metal film is covered with a resist film, and the resist film is patterned along the shapes of the excitation electrode 22, the input / output electrode 26, and the extraction electrode 24. After patterning the resist film, the electrode film 20 is obtained by etching the metal film using the patterned resist film as a mask, thereby forming the piezoelectric vibrating piece 12.

  Thereafter, the resist film is peeled off, and the piezoelectric vibrating reed 12 is mounted on the separately formed package base 32. After the piezoelectric vibrating reed 12 is mounted on the package base 32, the opening of the package base 32 is sealed with the lid 34, and the piezoelectric vibrator 10 is configured.

  According to the piezoelectric vibrator 10 having such a configuration, the productivity is excellent, and even when the amount of excavation of the mesa part (thick part 14) is made larger than before, the deterioration of the CI value can be suppressed. it can. Therefore, it becomes possible to determine the ratio Md of the moat amount in accordance with an appropriate value at which the CI value is good without worrying about overetching.

  In the above-described embodiment, it has been described that the package 30 constituting the piezoelectric vibrator 10 includes the box-shaped package base 32 and the flat lid 34. However, in the piezoelectric vibrator 10 according to the present invention, the package base may be a flat plate shape, and the lid may be a box-shaped so-called cap type.

  Next, a second embodiment according to the piezoelectric vibrator of the present invention will be described in detail with reference to FIG. Note that most of the configuration of the piezoelectric vibrator according to the present embodiment is the same as that of the piezoelectric vibrator according to the first embodiment described above. Therefore, portions having the same configuration are denoted by reference numerals obtained by adding 100 to the drawings, and detailed description thereof will be omitted. 6A is a diagram illustrating a front configuration of the mesa piezoelectric vibrator, and FIG. 6B is a diagram illustrating a planar configuration in a state of being transmitted through the lid.

The piezoelectric vibrator 110 according to the present embodiment is characterized in that the excitation electrode 122 extends to the thin portion 116 positioned on the extended line of the long side of the thick portion 114 (displacement direction of the main vibration).
In the present embodiment, the relationship between the long side dimension Mx of the thick portion 114, the long side dimension Ex1 of the excitation electrode, and the waveform λ of the bending displacement can be as follows (see FIG. 7). First, it is assumed that the long side dimension Mx of the thick portion 114 satisfies the relationship of Equation 4.

ここで、第１の実施形態でも説明したように励振電極の端縁部分を担うＬ１、Ｌ２の端縁部分は互いに屈曲変位の腹に一致させる必要があるため、

の関係を満たすようにする。 Next, the relationship between the long-side dimension of the thick portion 114 and the long-side dimension Ex1 of the excitation electrode 122 satisfies Equation 9.

Here, as described in the first embodiment, since the edge portions of L1 and L2 that bear the edge portion of the excitation electrode need to coincide with the antinodes of the bending displacement,

To satisfy the relationship.

  Further, regarding the relationship between the convex portion 118 and the edge portion of the excitation electrode 122, the relationship between L1 ≦ Sx and L2 ≦ Sx is established, so that the edge portion of the convex portion 118 and the edge portion of the excitation electrode 122 are separated. May match.

  In the piezoelectric vibrator 110 of the present embodiment satisfying such a relationship, as shown in FIG. 8, even when the ratio Md of the moat amount of the thick portion 114 is increased, the CI value is deteriorated (increased). It can be read that there is almost no. Therefore, even if it is a case where it is such a structure, the effect similar to the piezoelectric vibrator 10 which concerns on 1st Embodiment mentioned above can be acquired.

  Next, a third embodiment of the piezoelectric vibrator of the present invention will be described in detail with reference to FIG. Note that most of the configuration of the piezoelectric vibrator according to the present embodiment is the same as that of the piezoelectric vibrator according to the first embodiment described above. Therefore, portions having the same configuration are denoted by reference numerals obtained by adding 200 to the drawings, and detailed description thereof will be omitted.

  The piezoelectric vibrator 210 according to the present embodiment is characterized in that the convex portion 218 provided in the thin portion 216 is only the other end side (tip end portion) of the thin portion 216. Also in such a configuration, the thick portion 214, the excitation electrode 222, and the end portions of the convex portion 218 are configured to be at the antinodes of the bending displacement.

  In the case of such a configuration, when the convex portion 218 arranged so as to sandwich the thick portion 214 is only the tip end portion, when the ratio Md of the moat amount of the thick portion 214 is increased. Whether or not the deterioration of the CI value is affected is a problem. Accordingly, a change in the CI value accompanying a change in the moat amount ratio Md by the piezoelectric vibrator mounted with the piezoelectric vibrating piece according to the present invention in which the conditions other than the convex portion provided at the base side end portion are the same is simulated. Shown in In addition, the graph shown as convex on both sides in FIG. 10 shows the change in the CI value of the piezoelectric vibrator 10 according to the first embodiment, and the graph shown as convex on one side shows the CI value of the piezoelectric vibrator 210 according to this embodiment. It shows the change of.

  As is apparent from FIG. 10, even when the convex portion 218 is only on one side, the same effect as the piezoelectric vibrator according to the first embodiment described above can be obtained. Therefore, the piezoelectric vibrator 210 having such a configuration can also be a part of the present invention.

  DESCRIPTION OF SYMBOLS 10 ......... Piezoelectric vibrator, 12 ......... Piezoelectric vibrating piece, 14 ......... Thick part, 16 ......... Thin part, 18 ...... Convex part, 20 ...... Electrode film, 22 ...... Excitation Electrode, 24... Extraction electrode, 26... I / O electrode, 30... Package, 32... Package base, 34 ... Lid, 36 ... Seam ring, 38. Terminal, 40... External terminal, 42.

The present invention relates to a vibrating piece and a vibrator , and more particularly to a mesa-type vibrating piece in which the thickness dimension of a vibrating part is larger than that of a peripheral part and a vibrator on which the vibrating piece is mounted .

Further, in the configuration disclosed in Patent Document 4 in which mesa portions are formed in multiple stages in order to increase the relative moat amount, the CI value can be reduced, but the multi-stage mesa portions are formed. There is a concern that the number of photo processes to increase the productivity and the productivity will extremely deteriorate.
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a resonator element that is excellent in productivity and does not cause deterioration of the CI value even when the amount of excavation of the mesa portion is larger than that of the conventional one, and a vibrator including the resonator element. And

但し、ｌは正の整数、
の関係を満たし、
前記凸部の前記変位方向に沿った長さをＤｘ、
前記振動部と前記凸部との間の長さをＳｘとしたとき、
Ｄｘ＝（λ／２）×ｍ、
（λ／２）×ｎ−０．１×λ≦Ｓｘ≦（λ／２）×ｎ＋０．１×λ、
但し、ｍは正の整数、ｎは正の整数、
の関係を満たすことを特徴とする。
また、本発明のある別の形態に係る振動片は、更に、前記励振電極は、前記振動部から、前記振動部と前記凸部との間に位置する前記周辺部まで設けられ、
前記周辺部に延出されている前記励振電極の端縁と前記振動部の外縁との間の距離Ｌ１は、
Ｌ１＝（λ／２）×ｐ、
但し、ｐは正の整数
の関係を満たすことを特徴とする。
また、本発明のある別の形態に係る振動片は、前記素板の前記変位方向に沿った長さをＸ、
前記振動部の厚さをｔとしたとき、
Ｘ≧２０×ｔ
の関係を満たすことを特徴とする。
また、本発明のある別の形態に係る振動片は、前記素板が水晶板であり、
前記振動部と周辺部との段差部、および前記周辺部と前記凸部との段差部が傾斜面を有するとき、
前記Ｍｘ、前記Ｓｘ、および前記Ｄｘは、前記傾斜面の中心を端縁とし、当該端縁を起点としてそれぞれの寸法が定められることを特徴とする。
また、本発明のある別の形態に係る振動片は、前記凸部は、前記振動部の前記変位方向の両側のいずれか一方の前記周辺部に設けられていることを特徴とする。
また、本発明のある別の形態に係る振動片は、前記凸部の前記変位方向と交差する方向に沿った長さが、前記振動部の前記交差する方向に沿った長さと同じであることを特徴とする。
また、本発明のある別の形態に係る振動片は、前記周辺部の主面から前記凸部の主面までの高さが、前記周辺部の主面から前記振動部の主面までの高さと同じであることを特徴とする。
また、本発明のある別の形態に係る振動子は、前記振動片と、前記振動片が搭載されているパッケージと、
を備えていることを特徴とする。 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 resonator element according to an embodiment of the present invention includes a vibrating portion that vibrates in thickness and slips,
Integrated along at least the outer edge of the vibrating portion intersecting the displacement direction of the thickness-slip vibration, and a peripheral portion having a thickness smaller than that of the vibrating portion;
And convex portions provided in the peripheral portion,
Including a base plate,
An excitation electrode provided in the vibrating section;
Including
The length of the vibrating part along the displacement direction is Mx,
When the wavelength of the bending vibration generated along the displacement direction of the base plate is λ,

Where l is a positive integer,
Satisfy the relationship
The length of the convex portion along the displacement direction is Dx,
When the length between the vibrating part and the convex part is Sx,
Dx = (λ / 2) × m,
(Λ / 2) × n−0.1 × λ ≦ Sx ≦ (λ / 2) × n + 0.1 × λ,
Where m is a positive integer, n is a positive integer,
It is characterized by satisfying the relationship.
Further, in the resonator element according to another aspect of the invention, the excitation electrode is further provided from the vibrating portion to the peripheral portion located between the vibrating portion and the convex portion,
The distance L1 between the edge of the excitation electrode extending to the peripheral portion and the outer edge of the vibrating portion is:
L1 = (λ / 2) × p,
Where p is a positive integer
It is characterized by satisfying the relationship.
Further, in the resonator element according to another aspect of the invention, the length of the base plate along the displacement direction is X,
When the thickness of the vibrating part is t,
X ≧ 20 × t
It is characterized by satisfying the relationship.
Further, in the resonator element according to another aspect of the invention, the element plate is a crystal plate,
When the step portion between the vibrating portion and the peripheral portion, and the step portion between the peripheral portion and the convex portion have an inclined surface,
The Mx, the Sx, and the Dx are characterized in that each dimension is determined with the center of the inclined surface as an edge and the edge as a starting point.
Moreover, the resonator element according to another aspect of the invention is characterized in that the convex portion is provided on any one of the peripheral portions on both sides in the displacement direction of the vibrating portion.
Further, in the resonator element according to another aspect of the invention, the length of the convex portion along the direction intersecting the displacement direction is the same as the length of the vibrating portion along the intersecting direction. It is characterized by.
Further, in the resonator element according to another aspect of the invention, the height from the main surface of the peripheral portion to the main surface of the convex portion is high from the main surface of the peripheral portion to the main surface of the vibrating portion. It is characterized by the same.
A vibrator according to another aspect of the invention includes the vibrating piece, a package on which the vibrating piece is mounted,
It is characterized by having.

The piezoelectric vibrating reed 12 constituted by such a crystal element plate is constituted by a thick portion (vibrating portion) 14, a thin portion (peripheral portion) 16, a convex portion 18, and an electrode film 20. The thick portion 14 is defined in relation to the thin portion 16, and the thin portion 16 is provided around the thick portion 14. In the present embodiment, as described above, the thick portion 14 having a rectangular plane is stacked on the rectangular flat plate having the long side in the direction parallel to the X-axis of the crystal so that the long sides are parallel to each other. The integrated form is composed of a single base plate. The thick portion 14 is provided so as to be convex on both main surfaces of the thin portion 16.

Claims (6)

Piezoelectric vibration comprising a piezoelectric element plate having a vibration part that is surrounded by a peripheral part and has a larger thickness dimension than the peripheral part, and an excitation electrode disposed on the main surface of the piezoelectric element plate. A child,
Both the long side of the vibrating part and the long side of the excitation electrode are parallel to the long side of the piezoelectric element plate,
The long side dimension of the piezoelectric element plate is X, the thickness dimension of the vibration part is t, the long side dimension of the vibration part is Mx, and the long side dimension of the excitation electrode is Ex,
When the wavelength of the bending vibration generated in the longitudinal direction of the piezoelectric element plate is λ,

Satisfy the relationship
On the extended line in the longitudinal direction of the vibration part, it has a convex part arranged in parallel with the short side direction of the vibration part,
When the dimension in the displacement direction of the main vibration in the convex portion is Dx,

And when the dimension between the vibrating part and the convex part is Sx,

A piezoelectric vibrator characterized by satisfying the relationship: The piezoelectric vibrator according to claim 1,
The excitation electrode extends from the main surface of the vibration part to the peripheral part located between the convex part, and the distance from the vibration part to the edge portion of the excitation electrode extended to the peripheral part L1 is

A piezoelectric vibrator characterized by satisfying the relationship: The piezoelectric vibrator according to claim 1 or 2, wherein
The piezoelectric element plate is a quartz plate;
The step part between the vibration part and the peripheral part, and the step part between the peripheral part and the convex part have an inclined surface, and the dimensions of the vibration part, the dimensions from the vibration part to the convex part, and the convex part The dimension of each part is determined on the basis of the center of the inclined surface, respectively. The piezoelectric vibrator according to any one of claims 1 to 3,
The piezoelectric vibrator according to claim 1, wherein the convex portion is provided only on one end side of the vibration portion in the longitudinal direction. The piezoelectric vibrator according to any one of claims 1 to 4, wherein
A piezoelectric vibrator characterized in that a short side dimension of the convex part is matched with a short side dimension of the vibrating part. The piezoelectric vibrator according to any one of claims 1 to 5, wherein
A piezoelectric vibrator characterized in that a height of the vibration part and a height of the convex part with respect to the peripheral part are made the same.

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