JP4352738B2 - Tuning fork type piezoelectric vibrator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a tuning fork type piezoelectric vibration and a tuning fork type piezoelectric vibrator formed of a piezoelectric crystal such as quartz.
[0002]
[Prior art]
Piezoelectric vibrators, particularly tuning fork type piezoelectric vibrators, are known as being capable of easily obtaining an accurate clock frequency. In recent years, tuning fork-type piezoelectric vibrators have been reduced in size and thickness in response to downsizing and thinning of electronic devices, and so-called surface mount types have been developed. This surface-mount type tuning fork type piezoelectric vibrator has a tuning fork type piezoelectric vibrating piece mounted in a cantilever shape on the bottom surface of the package so that the surface of the tuning fork type piezoelectric vibrating piece is parallel to the bottom surface of the package. It is implemented by. Further, as a conventional tuning fork type piezoelectric vibrator, there is one in which a concave portion is formed on a bottom surface of a package corresponding to a tip portion of a vibrating arm portion of a tuning fork type piezoelectric vibrating piece (Patent Document 1). This is to prevent the tip of the vibrating arm portion of the tuning fork type piezoelectric vibrating piece from bending and colliding with the bottom of the package when an impact such as a drop acts on the tuning fork type piezoelectric vibrator.
[0003]
On the other hand, there is a tuning fork type piezoelectric vibrator shown in FIGS. 8 and 9 (Patent Document 2). FIG. 8 is a plan view showing an example of a conventional tuning fork type piezoelectric vibrator with a part thereof broken. FIG. 9 is a longitudinal sectional view of an example of a conventional tuning fork type piezoelectric vibrator. The conventional tuning fork type piezoelectric vibrator 100 is composed of a tuning fork type piezoelectric vibrating piece 115 and two cases 120 and 121 as shown in FIGS. The tuning fork type piezoelectric vibrator 115 is formed from a piezoelectric crystal such as quartz crystal, and includes a tuning fork type piezoelectric vibrating piece main body 113 including a base portion 110 and vibrating arm portions 111 and 112 that protrude from the base portion 110. With. The tuning fork type piezoelectric vibrating piece main body 115 is formed to be connected to the terminal side of the base 110 and has a frame 114 having a certain width surrounding the tuning fork type piezoelectric vibrating piece main body 113. The tuning fork type piezoelectric vibrator 100 is joined and sealed in a state where the frame part 114 is sandwiched between two cases 120 and 121. Further, the tuning fork type piezoelectric vibrator 100 is formed with projecting regions 114 a and 114 b in which the frame portion 114 partially projects from the sandwiching portions of the cases 120 and 121. Reference numerals 116 and 117 denote extraction electrodes.
[0004]
According to the conventional tuning fork type piezoelectric vibrator 100, the frame 114 has a larger width and the protrusion regions 114a and 114b are provided. Therefore, even if the metal bonding material protrudes, the metal bonding on the upper case 120 side is performed. Since the material and the metal bonding material on the lower case 121 side are not bonded, there is an advantage that there is no short circuit between the electrodes.
[0005]
[Patent Document 1]
JP 2001-332952 A [Patent Document 2]
Japanese Patent Laid-Open No. 56-61820
[Problems to be solved by the invention]
By the way, as described in Patent Document 1, a conventional tuning fork type piezoelectric vibrator generally has a tuning fork type piezoelectric vibrating piece mounted in a cantilever shape via a base. For this reason, in the conventional tuning fork type piezoelectric vibrator, the tuning fork type piezoelectric vibrating piece mounted in the package has a low parallelism and may be mounted obliquely. Therefore, in the conventional tuning fork type piezoelectric vibrator, the vibration arm portion may come into contact with the bottom surface of the package or the lid, and oscillation may stop. Further, the conventional tuning fork type piezoelectric vibrator has a recess formed on the bottom surface of the package in order to avoid contact between the vibrating arm portion and the bottom surface of the package. This recess needs to be set to a depth that can reliably prevent contact between the vibrating arm portion and the package, and it is difficult to make the tuning fork type piezoelectric vibrator thin. In addition, the conventional tuning fork type piezoelectric vibrator mounts (fixes) the base portion on which the vibrating arm portion protrudes on the bottom surface of the package, so that there is a problem that vibration leakage is large and the crystal impedance (CI) value increases. It was. Further, the conventional tuning fork type piezoelectric vibrator has a structure in which two electrodes of a tuning fork type piezoelectric vibrating piece and a mounting electrode on the package side are connected with a conductive adhesive between the two electrodes of vibration variation and the package. Since the distance between the mounting electrodes on the side is close, there is a possibility that the conductive adhesive protrudes and short-circuits between the electrodes.
An object of the present invention is to provide a tuning fork type piezoelectric vibrator that is thin, highly accurate and stable in view of the above problems.
[0007]
[Means to solve the problem]
In order to achieve the above object, a tuning fork type piezoelectric vibrating piece according to the present invention includes a vibrating piece main body including a base portion and a vibrating arm portion formed to protrude from the base portion, and the vibrating piece connected to the base portion. And a frame portion formed so as to surround the main body and provided with a mount portion at both ends.
[0008]
In the present invention configured as described above, the tuning fork type piezoelectric vibrating piece is accommodated in the package and mounted on the mounting portion provided on the frame portion. Can be implemented in parallel. Accordingly, it is not necessary to provide a recess in the package base in consideration of the collision between the tuning fork type piezoelectric vibrating piece and the package, and the height of the cavity for housing the tuning fork type piezoelectric vibrating piece of the package can be reduced. The piezoelectric vibrator (piezoelectric device) can be thinned. Further, since the tuning fork type piezoelectric vibrating piece of the present invention is mounted on the mount portion of the frame portion away from the vibrating arm portion, there is little vibration leakage and the crystal impedance (CI) value can be lowered.
[0009]
The mount part of the frame part can be provided at both ends in the longitudinal direction of the frame part. According to this configuration, since the pair of mount parts of the tuning fork type piezoelectric vibrating piece are arranged apart from each other, when mounted on the package (between the electrodes provided on the mounting part of the tuning fork type piezoelectric vibrating piece) There is no need to worry about short circuiting, and the mounting area can be reduced.
[0010]
The frame part can be provided with an alignment pattern for mounting on a package. As a result, the tuning fork type piezoelectric vibrating piece can be accurately positioned in the package, the cavity can be made smaller, and the package can be made smaller. A boundary portion between the base portion and the frame portion may be formed with a cut groove to reduce the width. Thereby, the vibration leakage to the frame part side can be reduced, and the vibration characteristics can be improved. The vibrating arm portion can form a groove on the front surface portion and the back surface portion. Thereby, the crystal impedance (CI) value of the tuning fork type piezoelectric vibrating piece can be lowered, and the tuning fork type piezoelectric vibrating piece can be reduced in size.
[0011]
A tuning fork type piezoelectric vibrator according to the present invention includes a tuning fork type piezoelectric vibrating piece, a package base in which the tuning fork type piezoelectric vibrating piece is fixed, and a lid for sealing the inside of the package base in a secret manner. In the tuning fork type piezoelectric vibrator, the tuning fork type piezoelectric vibrating piece includes a vibrating piece body including a base portion and a vibrating arm portion formed to protrude from the base portion, and is connected to the base portion to surround the vibrating piece body. And a frame portion provided with a mount portion, and the mount portion of the tuning-fork type piezoelectric vibrating piece is fixed to the package base with a conductive adhesive. That is, a tuning fork type piezoelectric vibrator according to the present invention has the above tuning fork type piezoelectric vibrating piece. Thereby, a piezoelectric vibrator having the above-described effects can be obtained.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Preferred embodiments of a tuning fork type piezoelectric vibrating piece and a tuning fork type piezoelectric vibrator according to the present invention will be described with reference to the accompanying drawings.
1 and 2 are explanatory views of a tuning fork type piezoelectric vibrator according to an embodiment of the present invention. FIG. 1 is a plan view of the tuning fork type piezoelectric vibrator according to the embodiment of the present invention in a state in which the tuning fork type piezoelectric vibrating piece is fixed to the base portion (package base) of the package. FIG. 2 is a cross-sectional view showing a tuning fork type piezoelectric vibrator according to an embodiment of the present invention.
[0013]
The tuning fork type piezoelectric vibrator 10 according to the embodiment of the present invention has a tuning fork type piezoelectric vibrating piece 20 housed in a package 30 as shown in FIGS. The tuning fork-type piezoelectric vibrating piece 20 is formed of a piezoelectric crystal such as quartz, and includes a vibrating piece main body 25 including a base portion 21 and vibrating arm portions 22 and 23 that protrude from the base portion 21. Further, the tuning fork type piezoelectric vibrating piece 20 includes a frame portion 24 formed in a shape surrounding the vibrating piece main body 25.
[0014]
As shown in FIG. 1, the frame portion 24 has wide mount portions 28 and 29 formed at both ends in the longitudinal direction. And the mount parts 28 and 29 are mutually connected by the two bridge | bridging parts 26 and 27 extended from these both sides. In addition, the frame portion 24 has an inner side of the mount portion 28 connected to the base portion 21, and the vibration piece main body 25 and the frame portion 24 are integrally formed. Further, the tuning fork type piezoelectric vibrating piece 20 is reduced in width by the cut grooves 36 formed on both sides in the width direction at the boundary portion between the base portion 21 of the vibrating piece main body 25 and the mount portion 28 of the frame portion 24. The vibration leakage of the piece body 25 is reduced.
[0015]
As shown in FIG. 2, the package 30 includes a base portion (package base) 31 made of ceramics such as alumina, a lid body 32 made of glass, and a sealing portion 33 made of low-melting glass. It is configured and has a box shape. As shown in FIG. 1, mount electrodes 34 and 35 having a predetermined interval are provided on the bottom of the base portion 31. Further, as shown in FIGS. 1 and 2, the tuning fork type piezoelectric vibrating piece 20 includes mount electrodes 34 and 35 formed by mounting portions 28 and 29 provided at both ends of the frame portion 24 on the base portion 31 of the package 30. Are joined by a conductive adhesive 38. As a result, the excitation electrode (not shown) of the tuning fork type piezoelectric vibrating piece 20 is electrically connected to the mount electrodes 34 and 35. That is, the tuning fork type piezoelectric vibrating piece 20 has excitation electrodes provided on the front and back surfaces and the side surfaces of the vibrating arm portions 22 and 23, and these excitation electrodes are mounted on the mount portions 28 and 29 of the frame portion 24. It is electrically connected to the provided connection electrode part (not shown) via a wiring pattern. In addition, the code | symbol 35a shown in FIG. 2 is a sealing hole at the time of vacuum-sealing the package 30. FIG.
[0016]
The tuning fork type piezoelectric vibrator 10 according to the embodiment thus configured can be mounted (mounted) on the package 30 via the mount portions 28 and 29 formed at both ends of the frame portion 24 of the tuning fork type piezoelectric vibrating piece 20. Therefore, the tuning fork type piezoelectric vibrating piece 20 can be disposed horizontally with respect to the bottom surface of the package 30. For this reason, the package 30 can lower the cavity in which the tuning fork type piezoelectric vibrating piece 20 is housed. Therefore, the tuning fork type piezoelectric vibrator 10 can reduce the overall thickness of the package 30 from the conventional 600 μm to about 300 to 400 μm, and can be thinned. Further, the tuning fork type piezoelectric vibrator 10 prevents the tuning fork type piezoelectric vibrating piece 20 from leaking vibration because the tuning fork type piezoelectric vibrating piece 20 is mounted via the mount portions 28 and 29 of the frame portion 24 instead of the base portion 21. Can do.
[0017]
Further, since the tuning fork type piezoelectric vibrating piece 20 has the pair of connection electrodes formed on the mount portions 28 and 29 provided at both ends of the frame portion 24, it is possible to reliably prevent a short circuit therebetween. In the tuning fork type piezoelectric vibrator 10 according to the embodiment, since the tuning fork type piezoelectric vibrating piece 20 is fixed to the package 30 by the mount portions 28 and 29 at both ends in the longitudinal direction, the tuning fork type piezoelectric vibrator 10 is resistant to impacts such as dropping. The piece 20 hardly swings up and down in FIG. For this reason, the square hole (concave part) conventionally formed in the tip part of the vibrating arm on the bottom surface of the package is not required, and stress concentration due to the formation of the square hole can be avoided and the strength of the package 30 can be improved. .
[0018]
FIG. 3 is a plan view showing a tuning fork type piezoelectric vibrating piece according to another embodiment of the present invention. In FIG. 3, the tuning fork type piezoelectric vibrating piece 20 is provided with mounting alignment patterns 41 and 42 on the bridging portions 26 and 27 of the frame portion 24. The alignment patterns 41 and 42 are for improving the positional accuracy when the tuning fork type piezoelectric vibrating piece 20 is mounted on the package 30, and are provided in a region near the mount portion 28. The bridge portions 26 and 27 close to the mount portion 29 of the frame portion 24 are provided with alignment patterns 43 and 44 that improve the positional accuracy when mounting. These mounting alignment patterns 41 to 44 are made of a gold thin film, like an excitation electrode (not shown) of the tuning fork type piezoelectric vibrating piece 20. Therefore, it can be formed simultaneously with the formation of the electrode. The tuning fork type piezoelectric vibrating piece 20 of the embodiment can grasp the inclination and position of the tuning fork type piezoelectric vibrating piece 20 with respect to the package 30 by the alignment patterns 41, 42, 43, and 44. When mounting on the 30 base portions 31, the mounting accuracy is remarkably increased.
[0019]
FIG. 4 is a plan view showing an example of an alignment pattern provided on the base portion of the package in order to manufacture the tuning fork type piezoelectric vibrator according to the embodiment of the present invention. In FIG. 4, alignment patterns 46 and 47 are provided on the inner bottom surface of the base portion 31 of the package 30 and on the left and right ends in the figure to improve the positional accuracy when the tuning fork type piezoelectric vibrating piece 20 is mounted. Yes. These alignment patterns 46 and 47 constitute a mount electrode. Since the alignment patterns 46 and 47 can accurately grasp the position of the tuning fork type piezoelectric vibrating piece 20 by the alignment patterns 41, 42, 43 and 44 of the tuning fork type piezoelectric vibrating piece 20, The mounting accuracy of the tuning fork type piezoelectric vibrating piece 20 is remarkably increased.
[0020]
FIG. 5 is a plan view showing another example of the mounting alignment pattern. In the tuning fork type piezoelectric vibrating piece 20, alignment patterns 41 a and 42 a that improve the positional accuracy when mounted on the package 30 are provided at the end corners of the mount portion 28 constituting the frame portion 24. Similarly, alignment patterns 43 a and 44 a are provided at the tip corners of the other mount portion 29. By these alignment patterns 41a, 42a, 43a, 44a, the mounting accuracy of the tuning fork type piezoelectric vibrating piece 20 in the package is remarkably increased.
[0021]
The alignment patterns 41 to 44, 46, 47, 41 a to 44 a may be any as long as the inclination and position of the tuning fork type piezoelectric vibrating piece 20 can be grasped.
6 is a plan view of a tuning-fork type piezoelectric vibrating piece according to still another embodiment, and FIG. 7 is a cross-sectional view taken along line AA of FIG. In the tuning fork type piezoelectric vibrating piece 50 according to this embodiment, groove portions 52 and 54 are formed in the vibrating arm portions 22 and 23. These groove portions 52 and 54 are formed symmetrically on the front surface side and the back surface side of the vibrating arm portions 22 and 23. For this reason, as for the vibrating arm parts 22 and 23, the cross section of the base end part by the side of the base 21 has comprised H shape (refer FIG. 7). The groove portions 52 and 54 have a width W that is 40 to 70% of the width of the vibrating arm portions 22 and 23, W ₀ . Further, the depth d of the groove portions 52 and 54 is set to 30 to 50% of the thickness D of the vibrating arm portions 22 and 23. Exciting electrodes (not shown) are formed in the groove portions 52 and 54. Thereby, the CI value of the tuning fork type piezoelectric vibrating piece 50 can be reduced, and the tuning fork type piezoelectric vibrating piece 50 can be formed in a smaller size.
[0022]
The tuning-fork type piezoelectric vibrating piece 10 according to the embodiment of the present invention is used in various electronic devices such as digital mobile phones, personal digital assistants, personal computers, television receivers, video devices, watches, and devices with built-in watches. Can be used. Moreover, although embodiment mentioned above is a suitable specific example of this invention, various technically preferable restrictions are attached | subjected, It is not restricted to these forms.
[Brief description of the drawings]
FIG. 1 is a plan view of a tuning fork type piezoelectric vibrator according to an embodiment.
FIG. 2 is a cross-sectional view of a tuning fork type piezoelectric vibrator according to an embodiment.
FIG. 3 is an explanatory diagram of an alignment pattern according to the embodiment.
FIG. 4 is an explanatory diagram of an alignment pattern provided in the package according to the embodiment.
FIG. 5 is an explanatory diagram of another alignment pattern according to the embodiment.
FIG. 6 is a plan view of a tuning-fork type piezoelectric vibrating piece according to another embodiment.
7 is a cross-sectional view taken along line AA in FIG.
FIG. 8 is a plan view showing an example of a conventional tuning fork type piezoelectric vibrator.
FIG. 9 is a longitudinal sectional view of an example of a conventional tuning fork type piezoelectric vibrator.
[Explanation of symbols]
10 ......... Tuning Fork Type Piezoelectric Vibrator, 20, 50 ......... Tuning Fork Type Piezoelectric Vibrating Piece, 21 ......... Base, 22, 23 ......... Vibrating Arm, 24 ......... Frame, 26, 27 ... ... Bridge part, 28, 29 ......... Mount part, 30 ......... Package, 31 ......... Package base (base part), 32 ...... Cover body, 36 ......... Cut groove, 52, 54 ......... Groove.

Claims (4)

In a piezoelectric vibrator comprising a tuning fork type piezoelectric vibrating piece, a package base in which the tuning fork type piezoelectric vibrating piece is fixed, and a lid for hermetically sealing the inside of the package base,
The tuning-fork type piezoelectric vibrating piece is formed to surround a vibrating piece main body having a base and a vibrating arm portion that protrudes from the base, and is connected to the base, and has a mount portion. A provided frame portion,
The frame part is provided with an alignment pattern for mounting on a package,
The package base is provided with an alignment pattern for mounting a tuning fork type piezoelectric vibrating piece,
Fixing the mount portion of the tuning-fork type piezoelectric vibrating piece to the package base with a conductive adhesive ;
The tuning fork type piezoelectric vibrator is characterized in that the tuning fork type piezoelectric resonator element mounting alignment pattern constitutes a mount electrode to which the mount portion is joined . The tuning fork type piezoelectric vibrator according to claim 1,
The tuning-fork type piezoelectric vibrator according to claim 1, wherein the mount portions of the frame portion are provided at both ends in the longitudinal direction of the frame portion. The tuning fork type piezoelectric vibrator according to claim 1 or 2 ,
A tuning fork type piezoelectric vibrator, wherein a width of a boundary portion between the base portion and the frame portion is reduced by a cut groove. The tuning fork type piezoelectric vibrator according to any one of claims 1 to 3 ,
A tuning-fork type piezoelectric vibrator, wherein the vibrating arm portion has grooves formed on a front surface portion and a back surface portion.

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