JP2023000464A - Crystal vibrating piece and crystal oscillator - Google Patents

Abstract

To provide a crystal vibrating piece having a structure in which a flat portion of a vibrating portion can be easily secured even when the thickness of a fixing part is thicker than that of the vibrating portion.SOLUTION: In a crystal oscillator 10, a fixing portion 23 provides a region along a first side 20a of a crystal vibrating piece 20. A vibrating portion 21 is provided on the side of a second side 20b facing the first side with respect to the fixing portion. Between the fixing portion and the vibrating portion, in a region parallel to the first side and extending from one end to the other end of the crystal vibrating piece, a slit 27 having a predetermined length Ls exceeding half the length of the first side is provided. The fixing portion includes a first fixing portion 23a in contact with the slit, and a second fixing portion 23b that is provided in a portion to which the slit does not extend and is recessed by a predetermined retreat dimension X2 toward the first side compared to the first fixing portion.SELECTED DRAWING: Figure 1

Description

The present invention relates to a crystal vibrating piece in which a vibrating portion and a fixed portion thicker than the vibrating portion are integrally formed, and a crystal vibrator using this crystal vibrating piece.

As one type of crystal vibrating piece, there is a crystal vibrating piece having a structure in which a vibrating portion and a fixed portion thicker than the vibrating portion are integrally formed. An example thereof is disclosed, for example, in Patent Document 1.
The crystal vibrating piece disclosed in Patent Document 1 uses an AT-cut crystal piece having a rectangular planar shape and one short side serving as a fixing portion to a container. Moreover, in this crystal vibrating piece, the thickness of the vibrating portion is set to a thickness corresponding to the desired vibration frequency, the thickness of the fixed portion is made considerably thicker than the thickness of the vibrating portion, and the thickness between the vibrating portion and the fixed portion is large. , has a through hole (see FIGS. 2(a) to 2(d) of Patent Document 1).

In the crystal vibrating piece disclosed in Patent Document 1, since the thicknesses of the vibrating portion and the fixed portion are greatly different, a buffer portion and an inclined portion are generated between the vibrating portion and the fixed portion. It is possible to suppress the influence of the fixed part on the vibrating part. Therefore, it is possible to prevent the crystal impedance value from increasing (paragraph 9 of Patent Document 1). In addition, since the through hole is provided, it is possible to suppress the influence of the buffer portion on the vibrating portion, and from this point as well, it is possible to prevent the crystal impedance value from increasing (paragraph 28 of Patent Document 1).

JP 2016-34061 A

However, as shown in the plan view of FIG. 4(A), in the crystal vibrating piece 100 disclosed in Patent Document 1, the vibrating portion 103 and the fixing portion are separated from the vibrating portion 103 and the fixed portion at each of the portions 100a on both sides of the through hole 101 in the longitudinal direction. 105 was connected. Therefore, a cross section along the long side of the crystal vibrating piece 100 passing through one of the above-described side portions 100a, that is, a cross section along line PP in FIG. 4A is as shown in FIG. 4B. In addition, the vibrating portion 103 will have a structure including a portion 103 a thicker than the original thickness of the vibrating portion 103 . Therefore, in the case of the crystal vibrating piece 100 disclosed in Patent Document 1, the flat portion 103b having the original thickness of the vibrating portion becomes narrower than the apparent vibrating portion 103 . In the case of crystal oscillators, generally speaking, the larger the effective area of the vibrating part, the better the characteristics, and the greater the degree of freedom in designing the crystal oscillator. .

This problem arises as the crystal oscillator becomes smaller. This problem will become even more serious in the future, as the demand for miniaturization of crystal oscillators is increasing.
This application has been made in view of these points, and therefore, an object of this application is to provide a structure in which the flat portion of the vibrating portion can be easily secured even if the fixed portion has a thickness greater than that of the vibrating portion. and a crystal vibrator using this crystal vibrating piece.

In order to achieve this object, according to the crystal vibrating piece invention of this application, there is provided a crystal vibrating piece that has a square planar shape and vibrates in a thickness-shear mode, and has a vibrating portion and a thickness thicker than the vibrating portion. A crystal vibrating piece having a structure in which a fixing portion for fixing to a container is integrally formed, and excitation electrodes are provided on the front and back sides,
The fixing portion is provided in a region along the first side of the crystal vibrating piece,
The vibrating portion is provided on a second side facing the first side with respect to the fixed portion,
Between the fixed part and the vibrating part, a region parallel to the first side and extending from one end to the other end of the crystal vibrating piece is half the length of the first side. A slit with a predetermined length exceeding
The fixing portion is provided in a first fixing portion in contact with the slit and in a portion not covered by the slit, and is set back by a predetermined receding dimension toward the first side compared to the first fixing portion. and a second fixing portion.

In carrying out the invention of the crystal vibrating piece, if the predetermined length of the slit is too short, the vibrating portion cannot be formed with a flat portion, and if it is too long, the vibrating portion tends to break near the boundary with the second fixing portion. . Therefore, when the predetermined length of the slit is represented by Ls and the length of the first side is represented by L1, Ls is preferably 0.55L1≤Ls≤0.75L1, preferably 0.55L1≤Ls. ≤0.7L1 is preferable, and 0.6L1≤Ls≤0.65L1 is more preferable.

In carrying out the invention of the crystal vibrating piece, if the predetermined receding dimension of the second fixing portion is too short, the desired flat portion cannot be formed in the vibrating portion. The fixing strength of is reduced. Therefore, when the dimension of the first fixing portion in the direction orthogonal to the first side is represented by X1, and the predetermined receding dimension of the second fixing portion is represented by X2, X2 is 0.2X1≦X2≦ 0.8X1 is good, preferably 0.3X1≤X2≤0.65X1, and more preferably 0.3X1≤X2≤0.5X1.

It should be noted that the dimension X1 of the first fixing portion is preferably as small as possible as long as the strength of the fixing portion can be obtained. This is because the area of the vibrating portion can be increased by doing so. When the dimension in the direction perpendicular to the first side of the crystal vibrating piece is represented by Lx, the dimension X1 of the first fixing portion is preferably 0.1Lx≤X1≤0.3Lx, preferably 0.3Lx. 15Lx≦X1≦0.25Lx is preferable.
In addition, when the dimension of the slit in the direction perpendicular to the first side of the crystal vibrating piece is represented by W, W should be as narrow as possible on the premise that it serves as a slit, that is, it penetrates the front and back of the crystal vibrating piece. preferable. This is because the area of the vibrating portion can be increased by doing so. Although not limited to this, when the thickness of the first fixing portion of the crystal vibrating piece is represented by T, the above dimension W is preferably 0.5T≤W≤3T, preferably 0.8T≤W≤1. 5T is good.

Further, according to the crystal resonator invention of this application, it is characterized by comprising the crystal resonator element of the invention described above and a container for mounting the crystal resonator element.

According to the crystal vibrating piece of the present invention, since the slit of a predetermined length with one end open is provided between the vibrating portion and the fixed portion, the flatness of the vibrating portion can be ensured to the immediate side of the slit on the vibrating portion side. can be secured. Moreover, in the region where the slit is not provided, the fixing portion is the second fixing portion which is recessed by a predetermined recession dimension toward the first side. can be retracted toward the first side, the flatness of the vibrating portion can be ensured even in the region without slits of the crystal vibrating piece. For these reasons, even if the crystal vibrating piece has a structure in which the fixed portion is thicker than the vibrating portion, a crystal vibrating piece having a structure in which the flat portion of the vibrating portion can be easily secured, and this crystal vibrating piece has been used. Crystal oscillators can be provided.

FIG. 1 is a diagram for explaining a crystal resonator 10 according to an embodiment. FIG. 2 is an explanatory diagram focusing on the crystal vibrating piece 20 of the embodiment included in the crystal resonator 10 of the embodiment. FIG. 3 is a diagram for explaining a modification of the crystal vibrating piece of the present invention. FIG. 10 is a diagram for explaining a problem of concern with the conventional crystal vibrating piece 100;

Embodiments of the present invention will be described below with reference to the drawings. It should be noted that each drawing used for explanation is only schematically shown to the extent that the present invention can be understood. In addition, in each drawing used for explanation, the same component may be denoted by the same number, and the explanation thereof may be omitted. Further, the shapes, materials, etc. described in the following embodiments are merely preferred examples within the scope of the present invention. Therefore, the present invention is not limited only to the following embodiments.

1. First Embodiment FIGS. 1A to 1C are diagrams for explaining a crystal resonator 10 according to an embodiment. Specifically, FIG. 1A is a plan view of the crystal oscillator 10, FIG. 1B is a cross-sectional view of the crystal oscillator 10 along line PP in FIG. 1A, and FIG. (C) is a cross-sectional view of the crystal resonator 10 taken along line QQ in FIG. 1(A). In addition, in FIG. 1(A), illustration of the lid member 43 shown in FIGS. 1(B) and 1(C) is omitted.
2A to 2C are diagrams focusing on the crystal vibrating piece 20 of the embodiment included in the crystal resonator 10 of the embodiment. Specifically, FIG. 2A is a plan view of the crystal vibrating piece 20, FIG. (C) is a cross-sectional view of the crystal vibrating piece 20 taken along line QQ in FIG. 2(A). However, illustration of the excitation electrodes is omitted in FIG.

A crystal resonator 10 of the embodiment includes a crystal vibrating piece 20 and a container 40 in which the crystal vibrating piece 20 is mounted.
The crystal vibrating piece 20 is a crystal vibrating piece 20 that has a square planar shape and vibrates in a thickness-shear mode. In this embodiment, the crystal vibrating piece 20 has a rectangular planar shape and is an AT-cut crystal vibrating piece. The crystal vibrating piece 20 is integrally formed with a vibrating portion 21 and a fixing portion 23 which is thicker than the vibrating portion 21 and fixed to the container 40, and has excitation electrodes 25 on the front and back.
The container 40 includes a base 41 and a lid member 43 that is connected to the base 41 and cooperates with the base 41 to form a closed space. The base 41 has a concave portion 41a having a rectangular planar shape for mounting the crystal vibrating piece 20 thereon. A connection pad 41b for mounting the crystal vibrating piece 20 is provided on the bottom surface of the concave portion 41a, and an external connection terminal 41c for connecting the crystal vibrator 10 to an external device is provided on the outer bottom surface of the base 41. FIG.
The connection pads 41b and the external connection terminals 41c are connected by via wiring or castellations (not shown).
The base 41 can be composed of, for example, a ceramic container. The lid member 43 has a flat plate shape and can be made of any structure and material according to the sealing method.

The fixing portion 23 of the crystal vibrating piece 20 is provided in a region along the first side 20a of the crystal vibrating piece 20 . The vibrating portion 21 is provided on the side of the second side 20b facing the first side 20a with respect to the fixed portion 23 . Between the fixed part 23 and the vibrating part 21, parallel to the first side 20a and from one end (specifically, the first long side 20c) to the other end (second A slit 27 having a predetermined length Ls exceeding half (L1/2) of the length L1 of the first side 20a is provided in a region toward the long side 20d). In addition, the fixing portion 23 has a first fixing portion 23a which is in contact with the slit 27, and a portion which is not reached by the slit 27 and which is located on the side of the first side 20a relative to the first fixing portion 23a. , and the second fixing portion 23b that is retracted.

The thickness T (see FIG. 2B) of the vibrating portion 21 is a thickness corresponding to the vibration frequency required for the crystal vibrating piece 20 . The fixed portion 23 has a predetermined thickness that is considerably thicker than the thickness T of the vibrating portion 21 .
The excitation electrodes 25 (see FIG. 1) are provided on predetermined regions on the front and rear surfaces of the vibrating portion 21, respectively. A lead wire 25a is led out from the excitation electrode 25 to the first side 20a side of the crystal vibrating piece 20 . In the case of the present invention, since the slit 27 is provided, the lead wiring 25a that is led out on the slit 27 side is detoured along the outline of the slit 27 and led out to the fixed portion 23 side.
The crystal vibrating piece 20 is connected and fixed to the connection pads 41b of the base 41 by a conductive adhesive 50 at the positions of the lead wires 25a.

Here, the predetermined length Ls of the slit 27 of the crystal vibrating piece 20 is half the length L1 of the first side 20a, that is, a predetermined length exceeding L1/2, as described above. If Ls is too short, the effect of the slits 27 does not reach the vibrating portion 21, leaving many non-flat regions in the vibrating portion 21. On the other hand, if Ls is too long, the vibrating portion 21 bends from the second fixing portion 23b. easier. According to the study of the inventor of this application, if Ls is longer than 0.75L1 with respect to L1, the probability that the vibrating portion 21 will break off from the second fixing portion becomes significant. It has been found that if it is short, the flat portion of the vibrating portion on the distal end side along the first side 20a of the slip 27 is too small, causing a problem. Then, judging from the examination of the ratio of Ls to L1, Ls is preferably 0.55L1 ≤ Ls ≤ 0.75L1, preferably 0.55L1 ≤ Ls ≤ 0.7L1, and more preferably 0.6L1 ≤ Ls≦0.65L1 is good.

Further, when X2 represents the predetermined receding dimension of the second fixing portion 23b, if X2 is too short, the effect of keeping the second fixing portion 23b away from the vibrating portion 21 is weakened. The thickness of the crystal piece becomes thicker than the predetermined thickness T at the boundary on the side. If X2 is too long, the fixing strength of the crystal vibrating piece 20 at the second fixing portion 23b is lowered. According to the study of the inventor of this application, when the dimension of the first fixing portion 23a in the direction perpendicular to the first side 20a is represented by X1, the above X2 for the second fixing portion 23b is greater than 0.8X1. It has been found that if it is large, the fixing strength of the crystal vibrating piece 20 at the second fixing portion 23b decreases, and if X2 is smaller than 0.2X1, the crystal vibrating piece 20 tends to have a region thicker than T. there is Therefore, X2 is preferably 0.2X1≤X2≤0.8X1, preferably 0.3X1≤X2≤0.65X1, more preferably 0.3X1≤X2≤0.5X1. The starting point of the receding dimension X2 is the position on the side of the first side 20a of the slit 27, and the end point of the receding dimension X2 is the position where the thickness of the second fixing portion 23b starts to be thicker than the thickness of the vibrating portion. , for example, the position where the thickness starts to increase by a factor of 1.1.

In the crystal oscillator 10 and the crystal vibrating piece 20 of the above-described embodiment, a desired flat region 29 (see FIG. 2) can be generated by the effect of the slit 27 in the portion of the vibrating portion 21 facing the first fixing portion 23a. A desired flat area 29 (see FIG. 2(C)) can be generated by the effect of retracting the second fixing portion 23b by a predetermined retraction dimension X2 in the portion of the vibrating portion 21 facing the second fixing portion 23b. can be done.

2. OTHER EMBODIMENTS In the above-described first embodiment, an example in which the second fixing portion 23b recedes in a straight line parallel to the long side 20c of the crystal vibrating piece 20 was shown. The method of retreating to the side of the first side 20a is not limited to this. For example, as shown in FIG. 3A, the receding boundary line is curved such that part of the second fixing portion 23b recedes convexly toward the first side 20a of the crystal vibrating piece 20. It's okay to be Further, as shown in FIG. 3B, even if the second fixing portion 23b is largely retracted toward the first side 20a on the first fixing portion 23a side and then gradually retracted. good.

Further, in the first embodiment described above, an example of a container including a base having a concave portion 41a and a cover member joined to the base is shown as the container 40. As shown in FIG. However, the container may have other constructions. For example, although not shown, it may be a container composed of a plate-like base and a cap-like lid member having a concave portion for enclosing the crystal vibrating piece 20 therein.
In addition, in the above-described first embodiment, an example of using an AT-cut crystal element as the crystal element is shown, but the present invention can also be applied to a so-called double-rotation crystal element such as an SC-cut crystal element. Invention can be applied.

10: Crystal resonator of the embodiment 20: Crystal resonator plate of the embodiment 20a: First side (first short side) 20b: Second side (second short side)
20c: first long side 21d: second long side 21: vibrating portion 23: fixed portion 23a: first fixed portion 23b: second fixed portion 25: excitation electrode 25a: extraction electrode 27: slit 29: flat region 40: Container 41: Base 43: Cover member 50: Conductive adhesive L1: Length of first side (first short side) Ls: Predetermined length of slit Lx: Length of long side of crystal vibrating piece X1: Length of first fixed part X2: Retraction dimension of second fixed part

Claims (8)

A crystal vibrating piece that has a rectangular planar shape and vibrates in a thickness-shear mode, wherein a vibrating portion and a fixing portion that is thicker than the vibrating portion and is fixed to a container are integrally formed. In a crystal vibrating piece having a structure with excitation electrodes on the front and back,
The fixing portion is provided in a region along the first side of the crystal vibrating piece,
The vibrating portion is provided on a second side facing the first side with respect to the fixed portion,
Between the fixed part and the vibrating part, a region parallel to the first side and extending from one end to the other end of the crystal vibrating piece is half the length of the first side. A slit with a predetermined length exceeding
The fixing portion is provided in a first fixing portion in contact with the slit and in a portion not covered by the slit, and is set back by a predetermined receding dimension toward the first side compared to the first fixing portion. and a second fixing portion. 2. The set forth in claim 1, wherein Ls is 0.55L1≦Ls≦0.75L1, where Ls is the predetermined length of the slit and L1 is the length of the first side. quartz crystal piece. 2. When the predetermined length of the slit is represented by Ls and the length of the first side is represented by L1, Ls satisfies 0.55L1≦Ls≦0.7L1. The described crystal vibrating piece. 2. When the predetermined length of the slit is represented by Ls and the length of the first side is represented by L1, Ls satisfies 0.6L1≦Ls≦0.65L1. The described crystal vibrating piece. When the dimension of the first fixing portion in the direction perpendicular to the first side is represented by X1, and the predetermined receding dimension of the second fixing portion is represented by X2, X2 is 0.2X1≤X2≤0. The crystal vibrating piece according to any one of claims 1 to 4, characterized in that it is .8X1. When the dimension of the first fixing portion in the direction orthogonal to the first side is represented by X1, and the predetermined receding dimension of the second fixing portion is represented by X2, X2 is 0.3X1≤X2≤0. 5. The quartz-crystal vibrating piece according to claim 1, characterized in that it is 0.65×1. When the dimension of the first fixing portion in the direction orthogonal to the first side is represented by X1, and the predetermined receding dimension of the second fixing portion is represented by X2, X2 is 0.3X1≤X2≤0. 5. The crystal vibrating piece according to any one of claims 1 to 4, characterized in that it is 0.5×1. A crystal vibrating piece comprising: the crystal vibrating piece according to any one of claims 1 to 7; and a container for mounting the crystal vibrating piece.

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