JP2004200910A - Tuning fork crystal oscillator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tuning fork crystal oscillator for surface mount the crystal impedance (CI) of which is enhanced. <P>SOLUTION: The tuning fork crystal oscillator is configured such that a tuning fork crystal chip comprising a tuning fork base and a pair of tuning fork arms is contained in a concaved package body having a bottom wall and frame walls, and the bottom side of the tuning fork base is adhered to an interior face of the frame walls of the package body by an adhesive, and lead electrodes extended to both sides of lower end of a principal side of the tuning fork base and crystal terminals provided to the package body are electrically connected by a conductive adhesive. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a tuning fork crystal resonator for surface mounting (hereinafter referred to as a tuning fork resonator) in the technical field of industry, and more particularly to a tuning fork resonator having improved crystal impedance (CI).
[0002]
[Prior art]
BACKGROUND OF THE INVENTION A tuning fork vibrator is used as a reference source especially for a timepiece, and is incorporated in various electronic devices. As one of such devices, there is a device in which a tuning fork-shaped quartz piece is housed in a surface mounting container main body to be a surface mounting type.
[0003]
(Example of Prior Art) FIGS. 4A and 4B are views of a tuning fork type vibrator for explaining a conventional example, wherein FIG. 4A is an assembly view excluding a cover 3 and FIG. 4B is a sectional view.
[0004]
The tuning fork type vibrator has a tuning fork-shaped quartz piece 2 housed in a container body 1, covered with a cover 3 and hermetically sealed. The container body 1 is made of a concave multilayer ceramic and has a bottom wall 4 and first and second frame walls 5 (ab). Mounting terminals 6 for surface mounting are provided on the bottom surface and side surfaces of a pair of diagonal portions of the bottom wall 4.
[0005]
One end of the first frame wall 5a protrudes into the concave portion of the container body 1 to form a divided step, and has a crystal terminal 7 on the surface. The crystal terminal 7 is connected to the mounting terminal 6 via a conductive path (not shown). A metal ring or the like (not shown) is formed on the upper surface of the second frame wall 5b.
[0006]
The tuning fork-shaped crystal piece 2 includes a tuning fork base and a pair of tuning fork arms. Excitation electrodes (not shown) are provided on the four surfaces of each tuning fork arm, and a pair of extraction electrodes (not shown) extend on both sides of the lower end of one main surface of the tuning fork base. Then, both sides of the extended lower end of the pair of extraction electrodes are electrically and mechanically connected to the crystal terminal 7 of the container body 1 by the conductive adhesive 8. The cover 3 is made of metal and is joined to the metal ring of the second frame wall 5b by seam welding or beam welding.
[0007]
[Problems to be solved by the invention]
(Problems of the prior art) However, in the tuning fork type vibrator having the above structure, the main surfaces on both sides of the lower end of the tuning fork base are fixed by the conductive adhesive 8. For this reason, there is a problem that the CI is increased as compared with, for example, the cylinder type tuning fork vibrator shown in FIG.
[0008]
That is, the bottom surface of the tuning fork-shaped crystal blank 2 is fixed to the surface of the circular base 11 with an insulating adhesive 9, and the CI is lower than that of the tuning fork type vibrator in which the extraction electrode is led out by the conductive adhesive 8. There was a problem of making it bigger. Note that the conductive adhesive 8 is used only for electrical connection, and mechanical connection is performed using the insulating adhesive 9.
[0009]
By the way, CI of the cylinder type tuning fork type vibrator is 35 KΩ, and 40 KΩ for the surface mounting in the above example, which is an increase of 5 KΩ. However, the external dimensions of the tuning fork-shaped crystal blank 2 are the same including the tuning fork arm.
[0010]
(Object of the Invention) An object of the present invention is to provide a tuning fork vibrator for surface mounting with improved CI.
[0011]
[Means for Solving the Problems]
(Points of Attention and Application) The present invention focused on a cylinder type holding structure, and applied this to a tuning fork vibrator for surface mounting.
[0012]
According to a first aspect of the present invention, there is provided an extraction electrode fixed to an inner surface of a frame wall of a container body having a concave bottom surface of a tuning fork by an adhesive, and extending to both sides of a lower end of a main surface of the tuning fork base. And a crystal terminal provided on the container body are electrically connected by a conductive adhesive. As a result, the bottom surface of the tuning fork base is fixed and the main surface is not entirely restrained, so that the CI is favorably maintained.
[0013]
In the second aspect, the container body has a step on one end side, and a pair of crystal terminals is formed on an upper surface of the step. In a third aspect, the container body has a pair of crystal terminals formed on a bottom wall. In a fourth aspect, the container body has a step on one end side and a pair of crystal terminals is formed on the upper surface, and the inner surface of the frame wall is a side surface of the step. Thus, the pair of crystal terminals and the extraction electrode of the tuning fork base can be electrically connected by the conductive adhesive.
[0014]
[First embodiment]
FIG. 1 is a view of a tuning-fork vibrator for explaining a first embodiment of the present invention. FIG. 1 (a) is a sectional view, and FIG. 1 (b) is a plan view excluding a cover 3. The same parts as those in the prior art are denoted by the same reference numerals, and description thereof will be simplified or omitted.
[0015]
As described above, the tuning-fork type vibrator accommodates the tuning-fork-shaped quartz piece 2 in the concave container body 1 composed of the bottom wall 4 and the first and second frame walls 5 (ab), covers the cover 3, and hermetically seals. Do it. The container main body 1 has a divided step portion having a crystal terminal 7 formed on the surface on one end side as described above.
[0016]
Then, the bottom surface of the tuning fork base is fixed to the inner wall surface of the second frame wall 5b with an insulating adhesive 9, and both ends of the lower end portion of the crystal piece from which the extraction electrode extends are pointed by the conductive adhesive 8. Connecting. The insulating adhesive 9 is made of epoxy, and the conductive adhesive 8 is made of flexible silicon.
[0017]
With such a configuration, the bottom surface of the tuning fork base is fixed and electrically connected pointwise by the conductive adhesive 8, so that the holding structure is equivalent to that of the cylinder type. Therefore, the CI is favorably maintained. Incidentally, the CI in this example was 35 KΩ as in the cylinder type. In this case, since the bottom surface of the tuning fork base is fixed to the inner surface of the frame wall of the second frame wall 5b, the length of the container body 1 can be reduced.
[0018]
[Second embodiment]
FIG. 2 is a diagram of a tuning-fork type vibrator for explaining a second embodiment of the present invention. The description of the same parts as those in the previous embodiment is simplified or omitted.
[0019]
In the first embodiment, a step is provided on one end side of the container body 1 to provide a gap between the tuning fork-shaped crystal blank 2 and the inner bottom surface. In the second embodiment, the thickness of the crystal terminal 7 is increased. Form a gap.
[0020]
Thereby, the container main body 1 can be formed into a two-layer structure of the bottom wall 4 and the frame wall 5, and the height can be reduced. Even in this case, since the bottom surface of the tuning fork base is fixed and electrically connected pointwise by the conductive adhesive 8, the CI is favorably maintained.
[0021]
[Third embodiment]
FIG. 3 is a diagram of a tuning-fork type vibrator for explaining a third embodiment of the present invention. FIG. 3 (a) is a sectional view, and FIG. 3 (b) is a plan view excluding the cover 3. The description of the same parts as those in the previous embodiment is simplified or omitted.
[0022]
In the third embodiment, the bottom surface of the tuning fork base is fixed to the inner surface of the frame wall of the first frame wall 5a with an insulating adhesive 9. Then, both sides of the lower end of the extended tuning fork base of the extraction electrode 10 are electrically connected to the crystal terminal 7 on the upper surface of the step portion by the conductive adhesive 8. Therefore, even in this case, since the holding structure is the same as that of the cylinder type, CI is improved.
[0023]
【The invention's effect】
The present invention provides an extraction electrode fixed to an inner surface of a frame wall of a container body having a concave bottom surface of a tuning fork and extending to both sides of a lower end of a main surface of the tuning fork base, and a crystal provided on the container body. Since the terminal and the terminal are electrically connected by the conductive adhesive, the CI is favorably maintained.
[Brief description of the drawings]
FIGS. 1A and 1B are diagrams of a tuning fork vibrator for explaining a first embodiment of the present invention, wherein FIG. 1A is a sectional view and FIG. 1B is a plan view excluding a cover.
FIG. 2 is a sectional view of a tuning-fork vibrator for explaining a second embodiment of the present invention.
3A and 3B are diagrams of a tuning-fork vibrator for explaining a third embodiment of the present invention, wherein FIG. 3A is a sectional view and FIG. 3B is a plan view excluding a cover.
4A and 4B are diagrams of a tuning fork type vibrator for explaining a conventional example, wherein FIG. 4A is an exploded view excluding a cover, and FIG. 4B is a cross-sectional view.
FIG. 5 is a front view of a tuning fork vibrator for explaining another example of the conventional example.
[Explanation of symbols]
1 container body, 2 tuning fork crystal pieces, 3 cover, 4 bottom wall, 5 frame wall, 6 mounting terminal, 7 crystal terminal, 8 conductive adhesive, 9 insulating adhesive, 10 extraction electrode, 11 base.

Claims (4)

In a tuning-fork type crystal resonator in which a tuning-fork-shaped crystal piece including a tuning-fork base and a pair of tuning-fork arms is housed in a concave-shaped container body having a bottom wall and a frame wall, a bottom surface of the tuning-fork base is formed by a frame of the container body. The extraction electrode, which is fixed to the inner surface of the wall with an adhesive, extends on both sides of the lower end of the main surface of the tuning fork base, and the crystal terminal provided on the container body is electrically connected by a conductive adhesive. Tuning fork type crystal unit. 2. The tuning-fork type crystal resonator according to claim 1, wherein the container body has a step on one end side and a pair of crystal terminals is formed on an upper surface of the step. 2. The tuning-fork type crystal resonator according to claim 1, wherein said container body has a pair of crystal terminals formed on both sides of one end of said bottom wall. 2. The tuning-fork type quartz resonator according to claim 1, wherein the container body has a step on one end side, and a pair of crystal terminals is formed on the upper surface, and an inner surface of the frame wall is a side surface of the step.

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