JPS60182814A - Piezoelectric vibrator and its sealing method - Google Patents

Abstract

PURPOSE:To prevent deterioration of a characteristic by providing a dense conductive agent part heated through high frequency induction heating to a sealing agent at a cross section at a right angle to a tangential line of a side face of a package in a piezoelectric vibrator applied with airtight sealing. CONSTITUTION:A lead terminal 2 is penetrated to an insulation material so as to form a base 3 of airtight structure in a piezoelectric vibrator 1. Moreover, a piezoelectric diaphragm 5 applied with an exciting electrode is fixed electrically and mechanically onto the lead terminal 2 with a conductive adhesives 6 or the like and the base 3 and a cover 4 form a package 10. The package 10 is formed as airtight structure, and a sealing agent 7 heated through high frequency induction heating is used in fixing and a conductive agent 8 is applied between the agents 7. Through the high frequency heating in this way, the package is sealed by the heating of the sealed part only and no adverse effect is given to the vibrator. Since the dense conductive agent part exists in a cross section of the sealing agent, the conductive agent is formed electrically in a form of ring.

Description

Detailed description of the invention [Technical field 1 of the present invention] The present invention relates to a piezoelectric vibrator hermetically sealed with a conductive agent that generates heat by high-frequency induction heating in the sealing material when the piezoelectric vibrator is hermetically sealed. Regarding the termination method.

[Description of Prior Art] Various methods of sealing chip-type piezoelectric vibrators have been published. Many of them use low-melting glass for hermetic sealing. This is because when mounting a chip-type piezoelectric vibrator on a substrate, it is necessary to seal the piezoelectric vibrator at a higher temperature than the solder so that the hermetically sealed portion does not peel off or leak due to the heat generated by the solder or the like. However, the melting point of low melting point glass is about 400℃, and the heating temperature is 400℃.
The temperature is around 30 degrees Celsius, and it takes a long time to heat up during sealing, which has a negative impact on the internal piezoelectric diaphragm and the adhesive that fixes the piezoelectric diaphragm. A sealing method was sought that would not affect the internal piezoelectric diaphragm.

[Objective/Structure 1 of the present invention] The object of the present invention is to eliminate the above-mentioned drawbacks, shorten the heating time, limit the heated part to the sealed part as much as possible, and prevent deterioration of the characteristics of the internal piezoelectric vibrator. Our objective is to provide a piezoelectric vibrator, and in order to achieve this purpose, in a piezoelectric vibrator that is hermetically sealed by high-frequency induction heating, high-frequency induction heating is applied to the sealed part side in a cross section perpendicular to the tangent to the side surface of the container. The main structure is that it has a densely packed part of a conductive agent that generates heat.

[Explanation of Examples] FIG. 1(a) is a perspective view of a piezoelectric vibrator 1 of the present invention.

FIG. 1(b) is a cross-sectional view of the piezoelectric vibrator l of the present invention,
A REIT terminal 2 passes through an insulating material such as ceramic or glass, and the REET terminal 2 forms a base 3 made of glass or the like and having an airtight structure. Further, a piezoelectric diaphragm 5 having an excitation electrode (not shown in this figure) provided on the lead terminal 2 is electrically and mechanically fixed with a conductive adhesive 6 or the like. Then, the base 3 and lid 4 are assembled to form a container 10. The container 10 is made to have an airtight structure, and a conductive agent 7 such as iron or Covar that generates heat by high-frequency induction heating is used for the low-melting glass on the sealing part side 7 used for fixing. First, container 1
A low melting point glass, which is the sealed part side 7, is put into a mold and compressed into a predetermined shape, which is a so-called tablet.

Then, a solidified conductive agent 8 in powder form or a liquid conductive agent 8 is applied between the two sealing parts 70 between the two sealing parts 70 . Such a state is shown in FIG. 3(a). Further, the sealing part side 7 is formed into a tablet, and a recess is provided in a part of the tablet, and the conductive agent 8 is filled in powder or in liquid form and poured into the recess. Such a state is shown in FIG. 3(b). Further, a conductive agent 8 is applied or placed on the surface of the tablet on the sealing part side 7. This state is shown in Figure 3 (c
). Then, the lid 4 is placed, and as shown in FIG. 2, a coil 9 used for high-frequency induction heating is placed near the sealing part side 7, and a high-frequency current is passed through the coil 9 to heat it. By passing a high frequency current through the coil, the conductive agent contained in the low melting point glass on the sealing portion side generates heat, melting the low melting point glass and sealing. As a result, heat was transmitted to the entire base up to the stand, but in the present invention, only the sealing part is heated by high-frequency induction heating, so the heating temperature of other parts during sealing can be kept low, and the piezoelectric There is no adverse effect on the characteristics of the vibrator.

The object to be heated by high-frequency induction heating must be a conductive material such as iron, and the object to be heated is preferably ring-shaped. The present application has been invented in accordance with this condition, and the cross section on the side of the sealed portion, which is a plane perpendicular to the tangent to the side surface of the container, that is, the cross section on the side of the sealed portion, is conductive to the sealed portion side. Make sure there are areas where the agent is densely packed. This is a necessary condition for the conductive agent described above to form an electrical ring.

In the present invention, although low melting point glass is used as the sealing material 7, other materials such as insulating adhesives may be used.

Further, although metals such as iron and copper are used as examples of the conductive agent mixed on the side of the sealed portion, any material may be used as long as it generates heat by induction heating.

Examples of piezoelectric materials include crystal resonators, piezoelectric ceramics, inks, and lithium tantalate.

[Effect 1 of the present invention] According to the present invention, the entire piezoelectric vibrator was conventionally heated, and as a result, the characteristics of the piezoelectric vibrator were adversely affected. However, according to the present invention, the heating temperature during sealing is limited only to the sealing member, and the piezoelectric sensor and other parts can be sealed without being heated, resulting in leakage defects and the piezoelectric vibrator. This prevents deterioration of the conductive adhesive that fixes the conductive adhesive, eliminates deterioration of the mechanical strength of the conductive adhesive, and makes it possible to obtain a stable piezoelectric vibrator. Additionally, the heating time required for sealing was shortened, improving workability and reducing man-hours. Furthermore, since the conductive material is electrically ring-shaped over the entire sealing area, the high-frequency induction heating can reliably and efficiently heat and seal the seal.

[Brief explanation of drawings]

FIG. 1(a) is a perspective view of a piezoelectric vibrator of the present invention. FIG. 1(b) is a sectional view of the piezoelectric vibrator of the present invention. Second
The figure is a cross-sectional view showing a state in which high-frequency induction heating is applied during sealing according to the present invention, and FIG. 3(a) is a partial cross-sectional view showing a state in which the conductive agent is placed on the sealing part with the conductive agent sandwiched between the sealing parts. Figure 1 (b) is a partial cross-sectional view showing a state in which a conductive agent is placed in a part of the sealing part side and placed on the sealing part, and Figure (c) is a partial cross-sectional view showing the state where the conductive agent is placed on the sealing part side. FIG. 4 is a partial sectional view showing a sealing portion according to another embodiment of the present invention. 6... Sealed part side, 8... Conductive agent, 10... Container (a) Figure 3 cb) (C) Procedure Amended writing format) % formula % 1. Indication of case 1981 Patent Application No. 039321 2
, Title of the invention Piezoelectric camera and its sealing method 3, Relationship with the case of the person making the amendment Patent applicant Postal code 201 Telephone number (03) 48! J-2311
May 29, 1982 (shipment date) 5. Column 6 for a brief explanation of the drawings in the specification subject to amendment. The figure excludes a partial sectional view showing a sealing part of another embodiment of the present invention.

Claims (4)

[Claims] (1) In a piezoelectric vibrator that is hermetically sealed by high-frequency induction heating, the sealing agent has a dense area of conductive material that generates heat by high-frequency induction heating in a cross section perpendicular to the tangent to the side surface of the container. Features a piezoelectric vibrator. (2) A step of attaching a conductive agent to the sealing agent, a step of placing the sealing agent on the sealing part of the container, and a step of installing a conductive agent in the vicinity of the sealing agent for high-frequency induction heating. A method for sealing a piezoelectric vibrator, characterized by a device that generates heat and is hermetically sealed by passing a high-frequency current through the device. (3) A method for sealing a piezoelectric vibrator according to claim 2, characterized in that the sealing member is provided with a recess, and the conductive agent is mounted in the recess. (4) The method for sealing a piezoelectric vibrator according to claim 2, characterized in that the conductive agent is attached to the surface of the sealing member.