JPH09102725A - Vibrator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve airtightness at a through-hole part by putting a metallic piece into the through-hole of a cover to form a metallic film by laser fusion. SOLUTION: A cover 3 has a conical through-hole 17 having a small diameter at the side of a diaphragm 1, and a conductor 18 is formed on the inner surface of the through-hole 17. Then a metallic piece is put into the through-hole 17 and irradiated by a laser within a vacuum tank. Thus the metallic piece is fused and a metallic film 22 is formed. In such a way, the metallic piece has fluidity when it is fused by the laser. As a result, the metallic piece can enter the through-hole 17 more smoothly and also can cover satisfactorily the upper small diameter part of the through-hole 17. Thus a sealing member is obtained by the conductor 18 and the film 22 to secure high airtightness. It is desirable to use chromium or titanium for the base of the conductor 18 and also to use indium, tin or zinc or an alloy of them to the film 22.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oscillator such as a crystal used for communication equipment.

[0002]

2. Description of the Related Art A conventional vibrator of this type includes a vibrating plate and first and second covers which cover the front and rear surfaces of the vibrating plate and sandwich the outer peripheral portion of the vibrating plate at its outer peripheral portion. Prepared,
The vibrating plate has a tongue-shaped vibrating portion inside the sandwiched portion by the first and second covers, and excitation electrodes are formed on the front and back surfaces of the vibrating plate.

Conventionally, the lead electrodes of the excitation electrodes on the front and back of the vibrating portion and the first and second external electrodes outside the first or second cover are connected to each other through the through holes of the first or second cover. It went through the conductor provided inside.

[0004]

In the above-mentioned conventional example, since the through hole provided in the first or second cover is formed by the sandblast method, large irregularities are formed on the inner wall surface of the through hole, or the through hole is formed. The edge of the penetration side of was partially chipped. Further, the through hole provided in the first or second cover is sealed only by the conductor formed by the vapor deposition method or the sputtering method. Since the particles deposited by the vapor deposition method or the sputtering method have a strong straight-line property, it was not possible to sufficiently cover the shadow of the large unevenness on the inner surface of the through hole and the chipping of the edge of the small diameter part, so the through hole can be reliably sealed. However, there was a problem that the airtightness of the through hole portion was low.

Therefore, an object of the present invention is to improve the airtightness in the through hole portion.

[0006]

In order to achieve this object, the present invention provides a vibrating plate and a first vibrating plate which covers the front and back surfaces of the vibrating plate and clamps the outer peripheral part of the vibrating plate at its outer peripheral part. A second cover and first and second external electrodes provided on the side opposite to at least one of the first and second covers, and the diaphragm includes the first and second outer electrodes. The cover has a tongue-like vibrating section inside the nipping section.Excitation electrodes are formed on the front and back surfaces of this vibrating section. Lead electrodes are drawn out through the root portion, one of the front and back lead electrodes forms a first connection portion, and the other lead electrode penetrates the one lead electrode side and then the second connection portion. And these first and second connecting parts are through holes of the first or second cover. A metal film in which the metal piece is melted by conducting the metal piece into the through hole of the cover and irradiating the metal film with the metal film is made conductive through the conductors provided on the surface, respectively. It is possible to provide the formed structure with excellent airtightness.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The invention according to claim 1 of the present invention includes a diaphragm and first and second diaphragms which cover the front and back surfaces of the diaphragm and sandwich the outer peripheral portion of the diaphragm with the outer peripheral portion thereof. No. 2 cover and first and second external electrodes provided on the side opposite to the diaphragm of at least one of the first and second covers, the diaphragm being the first and second covers. There is a tongue-shaped vibrating part inside the sandwiching part by the.The excitation electrodes are formed on the front and back sides of this vibrating part. Lead electrodes are led out through, one of the front and back lead electrodes forms a first connection portion, and the other lead electrode forms a second connection portion after penetrating to the one lead electrode side, The first and second connecting portions are conductors provided on the inner surface of the through hole of the first or second cover. A metal film is formed by being electrically connected to each of the first and second external electrodes via a laser beam and irradiating a metal piece put into the through-hole of the cover in a vacuum to form a metal film. Can be increased.

According to the second aspect of the present invention, the conductor provided on the inner surface of the through hole is formed by forming copper on the base of chromium or titanium to improve the adhesive force to the crystal.

According to the third aspect of the invention, indium, tin, lead, or an alloy thereof is used as the metal piece forming the metal film to obtain a reliable airtightness.

According to a fourth aspect of the present invention, the external electrode is caused to flow into the through hole formed with the metal film to further improve the airtightness.

(Embodiment 1) In FIG. 1, reference numeral 1 is a vibrating plate, which is composed of a quartz plate having a plate thickness of 100 μm. The covers 2 and 3 made of a crystal plate having a plate thickness of 400 μm are directly bonded to the front and back surfaces of the diaphragm 1. The external electrodes 4 and 5 in FIG. 1 are arranged on the diagonal line of the back surface of the cover 3. As shown in FIGS. 2 and 3, the vibrating plate 1 has a U-shaped cut groove 6 formed inward thereof, thereby forming a tongue-shaped vibrating portion 7.

Excitation electrodes 8 and 9 are formed on the front and back surfaces of the vibrating portion 7, and lead electrodes 11 and 12 thereof are drawn out via a root portion 10 of the vibrating portion 7, respectively. The end of the lead electrode 11 penetrates the diaphragm 1 through the through-hole 13 as shown in FIGS. 2 to 5, and then passes through the side of the vibrating part 7 as shown in FIG. To form a connection portion 14. Further, 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 via conductors 18 in through holes 16 and 17 formed in the cover 3 corresponding to the connection portions 14 and 15, respectively.

The covers 2 and 3 are provided with a diaphragm 1 at their outer peripheral portions.
Although the outer peripheral portions of the front and back surfaces are sandwiched and directly bonded, they are bonded at the outer peripheral portion of the kerf 6 of the diaphragm 1, and the lead electrode 11 is The portion passing the side is joined to the cover 3 on the outside.

In order to form the lead electrode 11 on the side of the vibrating portion 7 on the rear surface side of the diaphragm 1 as described above, the diaphragm 1 is covered with the covers 2, 3 as apparent from FIGS. 5 and 6. The plate thickness is made thick only at the sandwiching portion between the and, and the plate thickness is made thin by etching at the portions where the vibrating portion 7 and the lead electrodes 11 and 12 are formed. FIG. 4 clearly shows the diaphragm 1 after the etching step, and the thickness of the rear 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 which is sandwiched and joined by the covers 2 and 3.
As is apparent from the figure, the holding width 20 on the longitudinal side of the diaphragm 1
Is wider than the sandwiching width 21 in the short direction.

Since the lead electrode 11 is provided on the side of the vibrating portion 7 as shown in FIG. 3, the vibrating portion 7 is naturally deviated to one side from the central portion of the vibrating plate 1.

The cut groove 6 in the root portion 10 has a semicircular shape as shown in FIG. 4, so that cracks are less likely to occur even when an excessive impact is applied.

Now, the characteristic portion of this embodiment will be described. That is, in the present embodiment, FIGS.
As shown in FIG. 3, the through holes 16 and 17 provided in the cover 3 have a conical shape with a small diameter on the diaphragm 1 side (the penetrating side of the sandblast). Chromium or copper and titanium are attached by a vapor deposition method or a sputtering method to form the conductor 18. Chromium or titanium is deposited in hundreds to thousands of angstroms in order to strengthen the adhesion between crystal and copper, and copper is deposited in thousands of angstroms to several micrometers to establish conduction.

Above the conductor 18, the through holes 16 and 17 are provided.
And sealing the upper small diameter portion of the
5 is electrically connected, and below the conductor 18,
On the side of the cover 3 opposite to the diaphragm 1, the through holes 16,
It extends along the opening edge of 17.

In this state, a metal piece (the metal piece uses indium, tin, lead, or an alloy thereof) is put into the through holes 16 and 17 (at this time, the cover 3 is reversed from those in FIGS. 5 and 6). It is located above.) In this state, the vibrator is placed in a vacuum chamber, and a vacuum state (pressure 100
(Torr or less), the metal piece in the through holes 16 and 17 is irradiated with a laser, the metal piece is melted and allowed to flow into the through hole 16 and 17, and then the laser output is gradually reduced to gradually cool the metal. The metal film 22 is formed.

By melting the metal piece with a laser so as to have fluidity, the metal piece can easily flow into the through holes 16 and 17, and sufficiently cover the small diameter upper part of the through holes 16 and 17, so that the conductor 18 and the metal A good airtightness is ensured by forming a sealing body with the film 22.

Further, when the external electrodes 4, 5 are formed by screen printing or the like with the metal film 22 formed, a part of the external electrodes 4, 5 are formed in the through holes as shown in FIGS. 1, 5 and 6. It will fall slightly within 16,17. By forming the external electrodes 4 and 5 as a part of the sealing body, the airtightness is further enhanced.

[0022]

As described above, the present invention provides a diaphragm, first and second covers for covering the front and back surfaces of the diaphragm and sandwiching the outer peripheral portion of the diaphragm with the outer peripheral portion thereof. A first or second external electrode provided on the side opposite to at least one of the first and second covers of the diaphragm, wherein the diaphragm is inside the sandwiching portion by the first and second covers. It has a tongue-shaped vibrating part on the front side, and excitation electrodes are formed on the front and back sides of this vibrating part, and lead electrodes are respectively connected from the front and back excitation electrodes via the root of the vibrating part. One of the front and back lead electrodes forms a first connection portion, and the other lead electrode forms a second connection portion after penetrating to the one lead electrode side. The two connecting portions are respectively connected through the conductors provided on the inner surface of the through hole of the first or second cover. Note that the first and second external electrodes are electrically connected to each other, a metal piece is put into the through hole of the cover, and a molten metal film is formed by laser irradiation. Since the through hole of the cover is covered with the metal film not only on the conductor but also on the outer surface, the airtightness is enhanced.

Since the surface of the conductor is chromium or titanium, the adhesive force to the metal film of indium, tin or lead or the alloy film thereof is sufficiently strong.

Further, by making a part of the external electrode flow into the outer surface side of the sealing film of the through hole, the external electrode also becomes a part of the sealing body, and the airtightness is further enhanced.
A highly reliable oscillator can be provided.

[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 a surface state of the diaphragm shown in FIG. 1;

FIG. 3 is an exploded perspective view for explaining a back surface state of the diaphragm shown in FIG. 1;

FIG. 4 is a top view of the diaphragm.

FIG. 5 is a diagram A- of a vibrator in which a cover is joined to the diaphragm of FIG. 4;
A sectional view

FIG. 6 is a cross-sectional view of a vibrator in which a cover is joined to the vibrating plate of FIG.
B sectional view

[Explanation of reference numerals] 1 diaphragm 2 cover 3 cover 4 external electrode 5 external electrode 6 U-shaped groove 7 vibrating part 8 excitation electrode 9 excitation electrode 10 root 11 lead electrode 12 lead electrode 13 through hole 14 connection Part 15 Connection part 16 Through hole 17 Through hole 18 Conductor 22 Metal film

Claims (4)

[Claims] 1. A vibrating plate, first and second covers for covering the front and back surfaces of the vibrating plate and sandwiching the outer peripheral part of the vibrating plate with the outer peripheral part thereof, and the first or second cover. The first side provided on the side opposite to at least one of the diaphragms,
A second external electrode is provided, and the vibrating plate has a tongue-shaped vibrating portion inside the sandwiched portion by the first and second covers, and excitation electrodes are provided on the front and back surfaces of the vibrating portion. From these front and back excitation electrodes, lead electrodes are respectively drawn out through the roots of the vibrating parts, and one of these front and back lead electrodes forms the first connection part and the other lead is formed. The electrode forms a second connection portion after penetrating to the one lead electrode side,
These first and second connecting parts are electrically connected to the first and second external electrodes through conductors provided on the inner surface of the through hole of the first or second cover, respectively, and are connected to the inside of the through hole of the cover. An oscillator in which a metal film is formed by melting a metal piece put into a substrate and irradiating it with a laser in a vacuum. 2. The vibrator according to claim 1, wherein copper is formed on the conductor provided on the inner surface of the through hole by using chromium or titanium as a base. 3. The vibrator according to claim 1, wherein indium, tin, lead, or an alloy thereof is used as the metal piece. 4. The vibrator according to claim 1, wherein the external electrode is caused to flow into the through hole having the metal film formed therein.