JP3735917B2 - Vibrator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vibrator such as a crystal used in various communication devices.
[0002]
[Prior art]
This type of conventional vibrator includes a diaphragm and first and second covers that cover the front and back surfaces of the diaphragm and sandwich the outer periphery of the diaphragm at the outer periphery thereof, A tongue-shaped vibrating portion is provided inside the holding portion between the first and second covers, and excitation electrodes are formed on the front and back surfaces of the vibrating portion.
[0003]
The connection between the lead electrode of the excitation electrode on the front and back of the conventional vibration part and the first and second external electrodes outside the first or second cover is in the through hole of the first or second cover. It was performed via the provided conductor.
[0004]
[Problems to be solved by the invention]
As one of the reliability items, the flexural strength of the vibrator when mounted on a printed circuit board is required. Specifically, there should be no cracking or characteristic change of the vibrator at a deflection amount of at least 3 mm. However, the conventional example has a problem that the stress when the printed circuit board is bent is directly transmitted to the vibrator and is cracked.
[0005]
Accordingly, the object of the present invention is to improve the deflection strength of a vibrator.
[0006]
[Means for Solving the Problems]
In order to achieve this object, the present invention includes a diaphragm, first and second covers that cover the front and back surfaces of the diaphragm and sandwich the outer peripheral portion of the diaphragm at the outer peripheral portion thereof. First and second external electrodes provided on a side surface opposite to at least one diaphragm of the first or second cover, and the diaphragm has a tongue inwardly sandwiched by the first and second covers. It has a piece-like vibrating portion, and excitation electrodes are formed on the front and back surfaces of the vibrating portion, and lead electrodes are drawn out from the excitation electrodes on the front and back surfaces, respectively, through the root portion of the vibrating portion, One of the front and back lead electrodes forms a first connection part, and the other lead electrode forms a second connection part after penetrating on the one lead electrode side. The connecting portion is connected via a conductor provided on the inner surface of the through hole of the first or second cover. Each of the first and second external electrodes is electrically connected to the first and second external electrodes, and the first and second external electrodes have a higher melting point than the eutectic composition solder covering the conductor in the through hole. And a base electrode formed by applying a conductive resin paste obtained by kneading a curable resin to a conductive metal powder on the high-temperature solder film, and a solder layer formed on the base electrode. is there.
[0007]
With the above configuration, the flexural strength and airtightness of the vibrator are improved.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
The invention according to claim 1 of the present invention includes a diaphragm, first and second covers that cover the front and back surfaces of the diaphragm and sandwich the outer peripheral portion of the diaphragm with the outer peripheral portion thereof. First and second external electrodes provided on a side surface opposite to at least one diaphragm of the first or second cover, and the diaphragm has a tongue inwardly sandwiched by the first and second covers. It has a piece-like vibrating portion, and excitation electrodes are formed on the front and back surfaces of the vibrating portion, and lead electrodes are drawn out from the excitation electrodes on the front and back surfaces, respectively, through the root portion of the vibrating portion, One of the front and back lead electrodes forms a first connection part, and the other lead electrode forms a second connection part after penetrating on the one lead electrode side. The connecting part is connected to the front via a conductor provided on the inner surface of the through hole of the first or second cover. First, it is electrically connected to the second external electrode, the first and second external electrodes, in the through hole, and the high temperature solder film of a high melting point than covered eutectic composition solder the conductor, this It consists of a base electrode formed by applying a conductive resin paste obtained by kneading a curable resin to conductive metal powder on a high-temperature solder film, and a solder layer formed on this base electrode. Even if the printed circuit board on which the child is mounted is bent, the base electrode of the conductive resin paste of some of the first and second external electrodes serves as a buffer material to suppress the stress, thereby improving the bending strength of the vibrator. Have.
[0009]
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0010]
(Embodiment 1)
In FIG. 1, reference numeral 1 denotes a diaphragm, which is a quartz plate having a thickness of 100 μm. Covers 2 and 3 made of a quartz plate having a thickness of 400 μm are directly bonded to the front and back surfaces of the diaphragm 1. In addition, 4 and 5 in this FIG. 1 are arrange | positioned in the diagonal part of the back surface of the cover 3 with an external electrode. As shown in FIGS. 2 and 3, the diaphragm 1 has a U-shaped kerf 6 formed therein, thereby forming a tongue-shaped vibrating portion 7.
[0011]
Excitation electrodes 8 and 9 are formed on the front and back surfaces of the vibration part 7, and the lead electrodes 11 and 12 are drawn out through the root part 10 of the vibration part 7. As shown in FIGS. 2 to 5, the end portion of the inner lead electrode 11 penetrates the diaphragm 1 through the through hole 13, and then passes through the side of the vibrating portion 7 as shown in FIG. The connecting portion 14 is formed on the opposite side. The lead electrode 12 forms a connection portion 15 on the base portion 10 side. Then, they are connected to the external electrodes 4 and 5 through the conductors 18 in the through holes 16 and 17 formed in the cover 3 corresponding to these connection portions 14 and 15, respectively.
[0012]
The covers 2 and 3 sandwich the front and back outer peripheries of the diaphragm 1 at their outer peripheries and are directly joined to each other, but they are joined at the outer peripheries of the kerfs 6 of the diaphragm 1. In other words, the portion where the lead electrode 11 passes the side of the vibrating portion 7 is joined to the cover 3 on the outer side. Then, in order to form the lead electrode 11 on the back surface side of the vibration plate 1 on the side of the vibration portion 7 as described above, as is apparent from FIGS. 5 and 6, the vibration plate 1 includes the covers 2 and 3. Only the sandwiched portion is made thicker, and the portions where the vibrating portion 7 and the lead electrodes 11 and 12 are formed are made thinner by etching.
[0013]
FIG. 4 clearly shows the diaphragm 1 after this etching process, and the thickness of the back surface portion corresponding to the frame line 19 is reduced by etching. Further, the outer peripheral portion of the frame line 19 is a portion to be sandwiched and joined by the covers 2 and 3, and as is clear from FIG. 4, the sandwiching width 20 on the longitudinal direction side of the diaphragm 1 is sandwiched in the short direction. It is wider than the width 21.
[0014]
Further, since the lead electrode 11 is provided on the side of the vibration part 7 as shown in FIG. 3, the vibration part 7 is naturally shifted to one side from the center part of the diaphragm 1.
[0015]
In addition, the cut of the kerf 6 in the root portion 10 has a semicircular shape as shown in FIG. 4, which makes it difficult for cracks to occur even when an excessive impact is applied.
[0016]
Further, as shown in FIGS. 5 and 6, the through holes 16 and 17 provided in the cover 3 have a conical shape in which the diaphragm 1 side has a small diameter. Gold is deposited by vapor deposition or sputtering to form the conductor 18. At this time, chromium is deposited by several hundreds of angstroms in order to increase the adhesion between quartz and copper, and copper is deposited by several thousand angstroms to several μm. In some cases, several hundred to several thousand angstroms of gold are deposited to prevent copper oxidation in the manufacturing process.
[0017]
The upper portion of the conductor 18 seals the small diameter portion of the through holes 16 and 17 and is electrically connected to the connecting portions 14 and 15. The lower portion of the conductor 18 is connected to the diaphragm 1 of the cover 3. Extends to the opening edges of the through holes 16 and 17 on the opposite side.
[0018]
Further, for the purpose of improving the airtightness of the through holes 16 and 17, as shown in FIG. 7, the conductors 18 covering the small portions of the upper diameters of the through holes 16 and 17 are covered in the through holes 16 and 17. A high-temperature solder having a melting point higher than that of the eutectic composition solder in a fluidized state is introduced (at this time, the cover 3 is inverted from FIGS. 5 and 6 and positioned above), and becomes a high-temperature solder film 22. At this time, the high temperature solder film 22 is formed by a method such as printing or injection.
[0019]
Then, the characteristic part in embodiment of this invention is demonstrated. That is, as shown in FIGS. 5 and 6, on the back surface of the cover 3 and the high-temperature solder film 22 in the through holes 16 and 17, a conductive resin paste kneaded with a curable resin using copper as a conductive metal powder is screen-printed. The external electrodes 4 and 5 have a structure in which solder films 25 and 26 are formed on the base electrodes 23 and 24 applied and cured by the above method.
[0020]
(Embodiment 2)
Next, a vibrator in which an external electrode is also formed on the end face will be described. Basically, as shown in FIG. 8, FIG. 9, FIG. 10, FIG. 11, in the structure of the first embodiment, a conductive resin paste obtained by kneading a curable resin with conductive metal powder is printed or dipped on the end surface. Base electrodes 27 and 28 are applied and formed, and solder films 25 and 26 are formed thereon to form external electrodes. Although there are cases of two-terminal electrodes and four-terminal electrodes in terms of shape, both are structurally the same.
[0021]
What is important here is that when the end surface base electrodes 27 and 28 are applied and formed, they must be overlapped with each other in order to be electrically connected to the base electrodes 23 and 24. For this purpose, the printing conditions, dipping conditions, or the viscosity of the conductive resin paste are adjusted. However, the flexural strength of the vibrator is more advantageous as the number of surfaces is smaller than the three-surface electrode than the five-surface electrode and the two-surface electrode than the three-surface electrode. Therefore, it is necessary to suppress the wrapping around the surfaces of the covers 2 and 3 when forming the end surface base electrodes 27 and 28 as much as possible, and the amount thereof is 0.3 mm or less in sufficient contact with the base electrodes 23 and 24 on the cover 3. And
[0022]
Further, by rounding the ridge line of the vibrator by barrel polishing, it is possible to prevent the ridge line portion from being cut when the end surface base electrode is formed, and also to prevent occurrence of chipping against an impact such as dropping of the vibrator.
[0023]
(Embodiment 3)
Next, a method for improving the adhesion between the base electrodes 23 and 24 and the end face base electrodes 27 and 28 and the cover 3 and the vibrator end faces 29 and 30 in the first and second embodiments will be described. The solder films 25 and 26 can be formed by applying and melting solder dip or cream solder. However, the solder melted when forming the solder film penetrates into the porous base electrodes 23 and 24 and the end face base electrodes 27 and 28 and reaches the interface between the surface of the cover 3 and the vibrator end faces 29 and 30, and the base electrode 23, 24 and the end face underlying electrodes 27, 28 are reduced in adhesion.
[0024]
In order to suppress this phenomenon, the film thickness of the base electrodes 23 and 24 and the end face base electrodes 27 and 28 may be 40 μm or more. Further, the effect is enhanced by using a conductive resin paste forming film using nickel as the conductive metal powder as a barrier layer and a base electrode having a double structure.
[0025]
Further, since the surface of the cover 3 is a smooth surface etched and etched, it is considered that the anchor effect hardly acts on the adhesion between the base electrode and the surface of the cover 3. Accordingly, at least the surface of the cover 3 is roughened by sand blasting, thereby generating an anchor effect and improving the adhesion.
[0026]
Furthermore, the vibrator for communication is required to have long-term moisture resistance. However, it is considered that the base electrodes 23 and 24 and the surface of the cover 3 are in close contact with each other by an anchor effect and a covalent bond due to a hydroxyl group. When moisture enters the interface between the base electrodes 23 and 24 and the cover 3, the covalent bond is broken. There is a possibility that the base electrodes 23 and 24 may be peeled off and continuity cannot be obtained.
[0027]
Accordingly, if at least the surface of the cover 3 is subjected to a hydrophobic surface treatment, the moisture resistance of the adhesion is improved and a highly reliable vibrator is obtained. The same can be said for the end face base electrodes 27 and 28, but if the vibrator end faces 29 and 30 are also subjected to a hydrophobic surface treatment, the reliability becomes higher.
[0028]
【The invention's effect】
As described above, the present invention includes the diaphragm, the first and second covers that cover the front and back surfaces of the diaphragm and sandwich the outer peripheral portion of the diaphragm at the outer peripheral portion thereof, First and second external electrodes provided on a side surface opposite to at least one of the diaphragms of the second cover, and the diaphragm has a tongue-like shape inwardly of a sandwiched portion by the first and second covers Excitation electrodes are formed on the front and back surfaces of the vibration portion, and lead electrodes are drawn from the excitation electrodes on the front and back surfaces through the root portions of the vibration portions. One of the back lead electrodes forms a first connection part, and the other lead electrode forms a second connection part after penetrating to the one lead electrode side. These first and second lead electrodes The connecting part is connected to the front via a conductor provided on the inner surface of the through hole of the first or second cover. First, it is electrically connected to the second external electrode, the first and second external electrodes, in the through hole, and the high temperature solder film of a high melting point than covered eutectic composition solder the conductor, this It is composed of a base electrode formed by applying a conductive resin paste obtained by kneading a curable resin to conductive metal powder on a high-temperature solder film, and a solder layer formed on the base electrode .
[0029]
With the above configuration, even when the printed circuit board is bent, the base electrode formed of the conductive resin paste, which is a part of the first and second external electrodes, serves as a buffer material to transmit stress to the vibrator. Therefore, the deflection strength of the vibrator is improved. Furthermore, airtightness can be improved by a high-temperature solder film covering the conductor in the through hole.
[Brief description of the drawings]
FIG. 1 is a perspective view of a vibrator according to an embodiment of the present invention. FIG. 2 is an exploded perspective view for explaining the surface state of the diaphragm in FIG. 1. FIG. FIG. 4 is an exploded perspective view for explaining. FIG. 4 is a top view of the diaphragm. FIG. 5 is a cross-sectional view taken along line AA of the vibrator in which covers 2 and 3 are joined to the diaphragm shown in FIG. FIG. 7 is an enlarged cross-sectional view of the main part of another embodiment. FIG. 8 is a perspective view of a vibrator according to another embodiment. FIG. 10 is a cross-sectional view of the vibrator of another embodiment taken along the line AA. FIG. 11 is a cross-sectional view of the vibrator of another embodiment of FIG. Explanation】
DESCRIPTION OF SYMBOLS 1 Diaphragm 2 Cover 3 Cover 4 External electrode 5 External electrode 7 Vibration part 9 Excitation electrode 10 Root part 11 Lead electrode 12 Lead electrode 14 Connection part 15 Connection part 16 Through-hole 17 Through-hole 18 Conductor 22 High temperature solder film 23 Base Electrode 24 Base electrode 25 Solder film 26 Solder film 27 End face base electrode 28 End face base electrode 29 Vibrator end face 30 Vibrator end face

Claims (1)

A vibration plate, first and second covers that cover the front and back surfaces of the vibration plate and sandwich the outer peripheral portion of the diaphragm with the outer peripheral portion thereof, and vibrations of at least one of the first and second covers First and second external electrodes provided on the opposite side of the plate, and the vibration plate has a tongue-like vibration portion inwardly sandwiched by the first and second covers. Excitation electrodes are formed on the front and back surfaces, and lead electrodes are drawn out from the excitation electrodes on the front and back surfaces through the root portions of the vibration parts. One of the front and back lead electrodes is the first one. The other lead electrode penetrates the one lead electrode and then forms a second connection portion. These first and second connection portions penetrate the first or second cover. Conduction with the first and second external electrodes through a conductor provided on the inner surface of the hole, respectively. The first, the second external electrode, cured in the through-hole, and the conductor of the covered eutectic composition temperature solder film is also a high melting point of solder, on the high-temperature solder layer, a conductive metal powder A vibrator comprising a base electrode formed by applying a conductive resin paste kneaded with a mold resin, and a solder layer formed on the base electrode .

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