JPH03220910A - Piezoelectric vibrator - Google Patents

Abstract

PURPOSE:To obtain a piezoelectric vibrator with less frequency change even after aging for a long period by prolonging part of a metallic ring of a cylindrical or elliptic air-tight terminal in the lengthwise direction and welding the prolonged part with no glass in existence thereat and an opening of a case within the outside of the case. CONSTITUTION:A metallic ring 2 is prolonged to an outer lead 4 for welding at sealing. A case 9 is covered to an air-tight terminal 5 under vacuum or in an inactive gas to be set to a jig, and the prolonged part of the metallic ring 2 in the lengthwise direction with no glass in existence therein and an opening of a cylindrical case 9 without a guard are sealed by means of a laser welding or a parallel seam welding or the like while the case 9 and the air-tight terminal 5 are being turned to keep the air-tightness. The welding is to be implemented at a location as remote as possible from the glass 3 but no excess spacing is required and may be a half the length of the glass 3. Thus, the frequency change is reduced even in aging over a long period.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a piezoelectric vibrator.

[Conventional technology]

FIG. 7 shows a plan view of a conventional piezoelectric vibrator.

As shown in the figure, the cross section of a conventional piezoelectric vibrator is cylindrical.

FIG. 8 is a front view of a conventional piezoelectric vibrator.

The inner lead 21 is insulated and fixed by an outer metal ring 22 and glass 23, forming an airtight terminal 25.

The outer lead 24 is just an extension.

The rectangular piezoelectric oscillation piece 26 is attached to the electrode 27 using means such as vapor deposition.
It is formed.

This rectangular piezoelectric oscillation piece 26 and the inner lead 21 were fixed with solder 28.

Then, the frequency was adjusted by depositing Ag (not shown) or the like on the electrode 27 in a vacuum.

This was sealed by press-fitting the two cases and the airtight terminal 25 in a vacuum or an inert gas.

Incidentally, in order to maintain the sealing ventilation tightness, the outer periphery of the metal ring 22 and the case 28 were pre-plated with solder 30, etc., and after the sealing, the airtightness was maintained by fitting the airtight terminal 25 and the case 28.

[Problem to be solved by the invention]

However, since conventional technology uses solder to maintain airtightness, the frequency gradually changes due to the aging characteristics of leaving it for a long time due to the gas released from the solder and the loosening of the solder at the sealing part. It had the disadvantage of

Therefore, an object of the present invention is to provide a piezoelectric vibrator that exhibits little frequency change even during long-term aging.

[Means to solve the problem]

An inner lead is fixed to the same plane of a rectangular piezoelectric oscillator piece using an airtight terminal having a circular cross section and two or more leads insulated by an outer metal ring and glass. A part of the metal ring of the terminal is extended in the length direction, and the part without glass is sealed with a cylindrical case without a flange by welding inside the outer diameter of the case.

Furthermore, it is characterized by having an oval cross section.

Further, the rectangular piezoelectric oscillation piece is supported by a cantilever on the inner lead.

〔Example〕

Examples of the present invention will be described below.

FIG. 1 shows a plan view of a piezoelectric vibrator of the present invention, which has a circular cross section and a diameter of 3 mm.

FIG. 2 shows a front view of the piezoelectric vibrator of the present invention.

The side where the rectangular piezoelectric oscillation piece 6 is fixed is called the inner lead 1, and the side where the rectangular piezoelectric oscillation piece 6 is fixed is called the outer lead 4.
It is called.

Inner lead 1 and outer lead 4 are the outer metal ring 2
and is insulated by glass 3, forming an airtight terminal 5.

The metal ring 2 is extended toward the outer lead 4 for welding during sealing. The length of the extended metal ring without the glass 3 may be 1/2 of the length of the glass sealing portion. If it is made too long, it will only increase the length of the piezoelectric vibrator, so it is best to keep it to the minimum necessary size.

The rectangular piezoelectric oscillation piece 6 has a metal such as Ag formed as an electrode 7 on both sides at a thickness of about 3000 Amps using means such as vapor deposition, and a pattern is formed on the tip to establish electrical conduction with the inner lead 1. It is.

The rectangular piezoelectric oscillation piece 6 and the inner lead 1 are fixed in a cantilevered manner on the same plane using a conductive adhesive 8 or the like.

As the conductive adhesive 8, Ag paste or the like may be used.

Further, even if the rectangular piezoelectric oscillation piece 6 is fixed by applying solder or the like to the inner REIT 1 instead of the conductive adhesive 8, the effect on the characteristics etc. is small because the amount of solder is small.

Then, Ag or the like is deposited on the electrode 7 in vacuum to adjust the frequency.

This frequency adjustment amount is desirably 6000 PPM or less because the smaller the processing time, the more stable the characteristics.

Next, sealing is performed by covering the airtight terminal 5 with the case 9 in a vacuum or inert gas, setting it on a jig, and attaching the part without the glass 3 extending in the length direction of the metal ring 2. The case 9 and the airtight terminal 5 are connected by laser welding, parallel seam welding, etc. at the edge of the cylindrical case 9 without a brim.
It is sealed to prevent rotation and maintain airtightness.

The case 9 is made of nickel silver or the like, and is coated with Ni plating or the like. The material of the metal ring 2 is Kovar or the like, and similarly Ni plating or the like is used.

The reason why welding is not performed in the area where the glass 3 is located is that due to the rapid heating and cooling during welding, minute cracks are likely to form between the metal ring 2 and the glass 3, causing leaks and damaging the airtightness. .

It is better to weld as far away from the glass 3 as possible, but there is no need to make it extra long;
2 would be good too.

Another embodiment of the invention is shown in FIG.

In this case, by extending the metal ring 11 toward the inner lead 1 side, shortening the case 10, and performing welding, the length of the entire piezoelectric vibrator can be shortened compared to the method shown in FIG. 2.

FIG. 4 also shows another embodiment of the present invention, in which the metal ring 13 is extended toward the outer lead 4 side, and a collar 14 for receiving the case 12 is shown.
It is preferable to provide a holder and weld it to the case 12.

By attaching the collar 14, the positioning in the length direction when the case 12 is covered becomes possible, making it easier to manage the length when used as a piezoelectric vibrator.

If the outer diameter of the collar 4 is smaller than the outer diameter of the case 12, the piezoelectric vibrator can be made smaller. That is,
If the case 12 is 3 mm in diameter, the outer diameter of the collar 14 is 3 mm in diameter.
It shall be less than mm.

FIG. 5 is also a diagram showing another embodiment, which is a method for making welding easier.

The cut at the tip of the case 15 is processed so that the inside becomes longer as shown in the figure, and when the case 15 is put over the collar 14, only the inside of the case 15 comes into contact, and positioning in the length direction is performed.

By racer welding the gap on the outer periphery, the materials of the case 15 and the collar 14 are melted at the same time, making welding easier.

Furthermore, since the inner circumference of the case 15 is in contact with the collar 14,
Gas and dust during welding can be prevented from entering the case 15, and the properties of the piezoelectric vibrator after sealing are improved.

The cut of the case 15 should not be too acute to leave a gap with the collar 14, so it is preferable to make the cut of the case 15 less than 1 mm so that the two materials can easily melt during welding.

FIG. 6 is an elliptical cross-sectional view of an embodiment of the present invention.

By changing the case 15 and airtight terminal 5 from circular to oval as shown in FIG. 1, the thickness can be reduced and the device can be made smaller.

In Fig. 1, the diameter is 3 mm, but by making it elliptical, the width can be made 3 mm and the thickness 2 mm.

The shape is more flexible for parts such as mobile devices where thickness is limited.

〔Effect of the invention〕

The piezoelectric vibrator of the present invention can be manufactured by extending a part of the metal ring of a cylindrical or oval airtight terminal in the length direction and welding the part without glass within the outer shape of the case. Because it uses solder, there is no gas release from the solder.
We offer a piezoelectric vibrator that does not loosen due to solder press-fitting, has a cantilever structure, has no effect on the elongation of the piezoelectric oscillator piece due to temperature, has excellent aging characteristics, and can be made smaller due to its elliptical shape. be able to.

[Brief explanation of drawings]

FIG. 1 is a plan view of an embodiment of the present invention. FIG. 2 is a front view of an embodiment of the present invention. FIG. 3 is a front view showing another embodiment of the present invention. FIG. 4 is a front view showing another embodiment of the present invention. FIG. 5 is a front view showing another embodiment of the present invention. FIG. 6 is a plan view showing another embodiment of the present invention. FIG. 7 is a plan view of a conventional piezoelectric vibrator. FIG. 8 is a front view of a conventional piezoelectric vibrator. 1...Inner lead 2...metal ring 3...Glass 4...Outer lead 5...Airtight terminal 6... Rectangular piezoelectric oscillation piece 7... Electrode 8... Conductive adhesive 9...Case 10...case 11...metal ring 12...Case 13...metal ring 14◆・・・Brim 15・◆・Case 16...Airtight terminal 21...Inner lead 22...metal ring 23・ 24・ 25・ 26・ 27・ 28・ 29・ 30・ ・Glass ・Outer lead ・Airtight terminal ・Rectangular piezoelectric oscillation piece ·electrode ・Solder ·Case ·solder

Claims (1)

[Scope of Claims] 1) Using an airtight terminal having a circular cross section and two or more leads insulated by an outer metal ring and glass, the inner leads are two on the same plane of a rectangular piezoelectric oscillation piece. A part of the metal ring of this airtight terminal is extended in the length direction, and the part without glass is sealed by welding to the cylindrical case without a flange and the outside diameter of the case. Features a piezoelectric vibrator. 2) Claim 1) characterized in that the cross section is elliptical.
The piezoelectric vibrator described. 3) The piezoelectric vibrator according to claim 1, wherein the rectangular piezoelectric oscillating piece is supported by a cantilever of the inner lead.