JP2004297580A - Tuning fork type piezoelectric vibrating reed and tuning fork type piezoelectric vibrator - Google Patents

Abstract

A tuning fork type piezoelectric vibrator having a small thickness, high accuracy and stability is provided.
A tuning fork type piezoelectric vibrating piece constituting a tuning fork type piezoelectric vibrator includes a base and a vibrating arm formed with a vibrating piece protruding from the base. I have. Further, the tuning-fork type piezoelectric vibrating piece 20 has a frame portion 24 formed so as to surround the vibrating piece main body 25. The frame 24 has mounts 28 and 29 at both ends in the longitudinal direction. In the tuning fork type piezoelectric vibrating reed 20, mount portions 28 and 29 provided on the frame portion 24 are joined to mount electrodes 34 and 35 provided on the package 30.
[Selection diagram] Fig. 1

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a tuning fork type piezoelectric vibration and a tuning fork type piezoelectric vibrator formed from a piezoelectric crystal such as quartz.
[0002]
[Prior art]
2. Description of the Related Art Piezoelectric vibrators, particularly tuning-fork type piezoelectric vibrators, are known as those capable of easily obtaining an accurate clock frequency. In recent years, the tuning fork type piezoelectric vibrator has been reduced in size and thickness in response to the reduction in size and thickness of electronic devices, and a so-called surface mount type has been developed. This surface mount type tuning fork type piezoelectric vibrator has a tuning fork type piezoelectric vibrating piece mounted on the bottom of the package in a cantilever manner so that the surface of the tuning fork type piezoelectric vibrating piece is parallel to the bottom surface of the package. Implemented by Further, as a conventional tuning-fork type piezoelectric vibrator, there is a tuning-fork type piezoelectric vibrating piece in which a concave portion is formed on a package bottom surface corresponding to a tip end of a vibrating arm portion (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 against the package bottom surface when an impact such as dropping 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 in a partially broken manner. 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 includes a tuning-fork type piezoelectric vibrating piece 115 and two cases 120 and 121 as shown in FIGS. 8 and 9. The tuning-fork type piezoelectric vibrator 115 is formed of a piezoelectric crystal such as quartz, and has a base 110 and vibrating arms 111 and 112 protruding from the base 110 and a tuning-fork type piezoelectric vibrating piece main body 113. And The tuning-fork type piezoelectric vibrating reed main body 115 is formed to be connected to the terminal side of the base 110, and has a frame portion 114 having a constant width surrounding the tuning fork-type piezoelectric vibrating reed main body 113. The tuning fork type piezoelectric vibrator 100 is bonded and sealed with the frame 114 sandwiched between two cases 120 and 121. Further, the tuning fork type piezoelectric vibrator 100 has projection regions 114 a and 114 b where the frame portion 114 partially protrudes from the holding portions of the cases 120 and 121. Reference numerals 116 and 117 are extraction electrodes.
[0004]
According to the above-mentioned conventional tuning fork type piezoelectric vibrator 100, since the projections 114a and 114b are provided by enlarging the width of the frame portion 114, 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 a short circuit between the electrodes does not occur.
[0005]
[Patent Document 1] Japanese Patent Application Laid-Open No. 2001-332952 [Patent Document 2] Japanese Patent Application Laid-Open No. 56-61820 [0006]
[Problems to be solved by the invention]
By the way, in a conventional tuning fork type piezoelectric vibrator, as described in Patent Document 1, generally, a tuning fork type piezoelectric vibrating piece is 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 oscillation arm may come into contact with the bottom surface of the package or the lid, and oscillation may be stopped. Further, in the conventional tuning-fork type piezoelectric vibrator, a recess is formed on the bottom surface of the package in order to avoid contact between the vibrating arm and the bottom surface of the package. The concave portion needs to be set to a depth that can reliably prevent the contact between the vibrating arm portion and the package, and it has been difficult to reduce the thickness of the tuning-fork type piezoelectric vibrator. Also, in the conventional tuning-fork type piezoelectric vibrator, since the base from which the vibrating arm portion is formed is mounted (fixed) on the bottom surface of the package, there is a problem that the vibration leakage is large and the crystal impedance (CI) value increases. Was. Further, the conventional tuning-fork type piezoelectric vibrator has a disadvantage that when two electrodes of the tuning-fork type piezoelectric vibrating piece are connected to the mounting electrode on the package side with a conductive adhesive, the vibration-modulating two electrodes and the package Since the distance between the mounting electrodes on the side was short, there was a risk that the conductive adhesive would protrude and short-circuit would occur between the electrodes.
In view of the above problems, an object of the present invention is to provide a tuning fork type piezoelectric vibrator having a small thickness and high accuracy and stability.
[0007]
[Means to solve the problem]
In order to achieve the above object, a tuning-fork type piezoelectric vibrating reed according to the present invention includes a vibrating reed main body including a base and a vibrating arm formed so as to protrude from the base, and the vibrating reed connected to the base. And a frame portion formed around the main body and provided with mount portions at both ends.
[0008]
According to the present invention, the tuning fork type piezoelectric vibrating piece is housed in the package and mounted on the mounting portion provided on the frame portion. Can be implemented in parallel. Therefore, it is not necessary to provide a concave portion in the package base in consideration of the collision between the tuning fork type piezoelectric vibrating reed and the package, and the height of the cavity for accommodating the tuning fork type piezoelectric vibrating reed of the package can be reduced. The thickness of the piezoelectric vibrator (piezoelectric device) can be reduced. In addition, since the tuning-fork type piezoelectric vibrating reed of the present invention is mounted on the mount portion of the frame portion remote from the vibrating arm, vibration leakage is small, and the crystal impedance (CI) value can be reduced.
[0009]
The mounts of the frame may be provided at both ends in the longitudinal direction of the frame. According to this configuration, since the pair of mount portions of the tuning fork type piezoelectric vibrating reed are arranged apart from each other, when the package is mounted (mounted) on the package, between the electrodes provided on the mount portion of the tuning fork type piezoelectric vibrating reed. There is no need to worry about a short circuit, and the mounting area can be reduced.
[0010]
The frame portion can be provided with an alignment pattern for mounting on a package. Thereby, the tuning fork type piezoelectric vibrating reed can be accurately positioned in the package, the cavity can be made smaller, and the package can be made smaller. The boundary between the base and the frame may be formed with a cut groove to reduce the width. Thereby, vibration leakage to the frame portion side can be reduced, and the vibration characteristics can be improved. The vibrating arm can form grooves on the front surface and the back surface. Thereby, the crystal impedance (CI) value of the tuning-fork type piezoelectric vibrating reed can be reduced, and the tuning fork-type piezoelectric vibrating reed 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 hermetically sealing the inside of the package base. In the tuning-fork type piezoelectric vibrator, the tuning-fork type piezoelectric vibrating piece includes a vibrating piece main body including a base and a vibrating arm formed to protrude from the base, and surrounds the vibrating piece main body connected to the base. And a frame part provided with a mount part, wherein the mount part of the tuning-fork type piezoelectric vibrating reed is fixed to the package base by a conductive adhesive. That is, a tuning-fork type piezoelectric vibrator according to the present invention includes the above-described tuning-fork type piezoelectric vibrating piece. As a result, a piezoelectric vibrator having the above operation and effect can be obtained.
[0012]
BEST MODE FOR CARRYING OUT 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.
FIGS. 1 and 2 are explanatory diagrams of a tuning-fork type piezoelectric vibrator according to an embodiment of the present invention. FIG. 1 is a plan view of a tuning fork type piezoelectric vibrator according to an embodiment of the present invention, in which a tuning fork type piezoelectric vibrating piece is fixed to a package base (package base). FIG. 2 is a cross-sectional view showing the tuning-fork type piezoelectric vibrator according to the embodiment of the present invention.
[0013]
As shown in FIGS. 1 and 2, 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. The tuning-fork type piezoelectric vibrating reed 20 is formed of a piezoelectric crystal such as quartz and has a vibrating reed main body 25 having a base 21 and vibrating arms 22 and 23 protruding from the base 21. Further, the tuning-fork type piezoelectric vibrating piece 20 has 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. The mounts 28 and 29 are connected to each other by two bridges 26 and 27 extending from both sides thereof. In the frame portion 24, the inside of the mount portion 28 is connected to the base portion 21, and the resonator element 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 cutting grooves 36 formed on both sides in the width direction at the boundary between the base 21 of the vibrating piece main body 25 and the mount section 28 of the frame 24. The vibration leakage of the one main body 25 is reduced.
[0015]
As shown in FIG. 2, the package 30 includes a base (package base) 31 made of ceramics such as alumina, a lid 32 made of glass, and a sealing part 33 made of low-melting glass. It has a box-like shape. At the bottom of the base 31, mount electrodes 34, 35 are provided at predetermined intervals, as shown in FIG. As shown in FIGS. 1 and 2, the tuning fork type piezoelectric vibrating reed 20 includes mount electrodes 28, 29 provided at both ends of a frame 24, and mount electrodes 34, 35 formed on a base 31 of the package 30. Are joined by a conductive adhesive 38. Thus, the excitation electrodes (not shown) of the tuning-fork type piezoelectric vibrating piece 20 are electrically connected to the mount electrodes 34 and 35. That is, in the tuning-fork type piezoelectric vibrating reed 20, excitation electrodes are provided on the front surface, the back surface, and each side surface of the vibrating arms 22 and 23, and these excitation electrodes are mounted on the mounts 28 and 29 of the frame 24. It is electrically connected to the provided connection electrode section (not shown) via a wiring pattern. Reference numeral 35a shown in FIG. 2 is a sealing hole when the package 30 is vacuum-sealed.
[0016]
The tuning fork type piezoelectric vibrator 10 according to this embodiment can be mounted (mounted) on the package 30 via the mounting portions 28 and 29 formed on both ends of the frame portion 24 of the tuning fork type piezoelectric vibrating piece 20. Therefore, the tuning fork type piezoelectric vibrating reed 20 can be arranged horizontally with respect to the bottom surface of the package 30. For this reason, in the package 30, the cavity for accommodating the tuning-fork type piezoelectric vibrating piece 20 can be reduced. Therefore, the entire thickness of the package 30 of the tuning-fork type piezoelectric vibrator 10 can be reduced from 600 μm in the related art to about 300 to 400 μm, and the thickness can be reduced. Further, in the tuning-fork type piezoelectric vibrator 10, since the tuning-fork type piezoelectric vibrating piece 20 is mounted via the mounts 28 and 29 of the frame 24 instead of the base 21, it is possible to prevent the tuning fork-type piezoelectric vibrating piece 20 from leaking. Can be.
[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 between the two. Further, in the tuning fork type piezoelectric vibrator 10 of 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 and the like. The piece 20 hardly swings in the vertical direction in FIG. For this reason, the square hole (recess) conventionally formed at the tip 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 reed according to another embodiment of the present invention. In FIG. 3, the tuning fork type piezoelectric vibrating reed 20 has mounting alignment patterns 41 and 42 provided on bridge portions 26 and 27 of a frame portion 24. The alignment patterns 41 and 42 are for improving the positional accuracy when the tuning fork type piezoelectric vibrating reed 20 is mounted on the package 30, and are provided in a region close to the mount 28. The bridge portions 26 and 27 of the frame portion 24 near the mount portion 29 are provided with alignment patterns 43 and 44 for improving positional accuracy when mounting. These mounting alignment patterns 41 to 44 are made of a gold thin film, like the excitation electrodes (not shown) of the tuning-fork type piezoelectric vibrating piece 20. Therefore, they can be formed simultaneously with the formation of the electrodes. The inclination and position of the tuning fork type piezoelectric vibrating piece 20 with respect to the package 30 can be grasped by the alignment patterns 41, 42, 43, and 44 of the tuning fork type piezoelectric vibrating piece 20 of the embodiment. When mounting on the base part 31 of 30, the mounting accuracy becomes extremely high.
[0019]
FIG. 4 is a plan view showing an example of an alignment pattern provided on a base portion of a package for manufacturing the tuning-fork type piezoelectric vibrator according to the embodiment of the present invention. In FIG. 4, alignment patterns 46 and 47 for improving the positional accuracy when the tuning fork type piezoelectric vibrating piece 20 is mounted 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 drawing. I have. These alignment patterns 46 and 47 constitute a mount electrode. 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 reed 20 is significantly increased.
[0020]
FIG. 5 is a plan view showing another example of the mounting alignment pattern. In the tuning-fork type piezoelectric vibrating reed 20, alignment patterns 41 a and 42 a for improving the positional accuracy when mounted on the package 30 are provided at the terminal corner of the mount 28 constituting the frame 24. Similarly, alignment patterns 43a and 44a are provided at the tip corner of the other mount portion 29. Due to these alignment patterns 41a, 42a, 43a, and 44a, the mounting accuracy of the tuning fork type piezoelectric vibrating piece 20 in the package is significantly increased.
[0021]
The alignment patterns 41 to 44, 46, 47, 41a to 44a may be of any type as long as the inclination and the position of the tuning-fork type piezoelectric vibrating piece 20 can be grasped.
FIG. 6 is a plan view of a tuning-fork type piezoelectric vibrating reed according to still another embodiment, and FIG. 7 is a sectional view taken along line AA of FIG. In the tuning-fork type piezoelectric vibrating piece 50 according to this embodiment, grooves 52 and 54 are formed in the vibrating arms 22 and 23. These grooves 52 and 54 are formed symmetrically on the front side and the back side of the vibrating arms 22 and 23. For this reason, the vibrating arms 22 and 23 have an H-shaped cross section at the base end on the base 21 side (see FIG. 7). Each groove 52 and 54, the width W is in the range of the vibrating arms 22, 23 and 40% to 70% of _{W 0.} The depth d of the grooves 52 and 54 is 30 to 50% of the thickness D of the vibrating arms 22 and 23. Excitation electrodes (not shown) are formed inside the grooves 52 and 54. Thus, 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 more compact.
[0022]
The tuning-fork type piezoelectric vibrating piece 10 according to the embodiment of the present invention can be used for various electronic devices such as a digital mobile phone, a portable information terminal, a personal computer, a television receiver, and a video device, a clock, and a device with a built-in clock. Can be used. Further, the above-described embodiments are preferred specific examples of the present invention, and various technically preferable limitations are added thereto, but the present invention is not limited to these embodiments.
[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 the tuning-fork type piezoelectric vibrator according to the 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 on 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 reed according to another embodiment.
FIG. 7 is a sectional view taken along line AA of FIG. 6;
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]
Reference numeral 10: Tuning fork type piezoelectric vibrator, 20, 50: Tuning fork type piezoelectric vibrating reed, 21: Base, 22, 23: Vibrating arm, 24: Frame, 26, 27 ... ... Bridge section, 28, 29... Mount section 30, 30 Package, 31 Package base (base section), 32 Lid, 36 Cut groove, 52, 54. Groove.

Claims (6)

A resonator element main body including a base and a vibrating arm formed to protrude from the base;
A frame portion connected to the base portion and formed around the vibrating piece main body and provided with a mount portion;
A tuning-fork type piezoelectric vibrating reed comprising: The tuning fork type piezoelectric vibrating reed according to claim 1,
A tuning-fork type piezoelectric vibrating reed, 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 vibrating reed according to claim 1 or 2,
The tuning fork-type piezoelectric vibrating reed, wherein the frame portion is provided with an alignment pattern for mounting on a package. The tuning-fork type piezoelectric vibrating reed according to any one of claims 1 to 3,
A tuning-fork type piezoelectric vibrating reed, wherein a boundary between the base and the frame has a width reduced by a cut groove. The tuning-fork type piezoelectric vibrating reed according to any one of claims 1 to 4,
A tuning-fork type piezoelectric vibrating reed, wherein the vibrating arm has grooves formed on a front surface and a back surface. A tuning fork type piezoelectric vibrating piece, a package base in which the tuning fork type piezoelectric vibrating piece is fixed, and a piezoelectric vibrator including a lid for hermetically sealing the inside of the package base.
The tuning-fork type piezoelectric vibrating reed includes a vibrating reed main body including a base and a vibrating arm formed to protrude from the base, and is formed to surround the vibrating reed main body connected to the base, and a mount portion is provided. Having a provided frame portion,
A tuning fork type piezoelectric vibrator, wherein the mount portion of the tuning fork type piezoelectric vibrating piece is fixed to the package base by a conductive adhesive.

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