JPS604390Y2 - airtight terminal - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an airtight terminal, particularly an airtight terminal used as a header for holding a crystal resonator.

2. Description of the Related Art As an airtight terminal used as a header for holding a disk-shaped crystal resonator, there is a structure shown in FIGS. 1 and 2.

In the figure, reference numeral 1 denotes an inverted boat-shaped metal outer ring, and a top plate 2 of which has circular through holes 3, 3 bored near both ends in the longitudinal direction.

Lead wires 4 and 4 are inserted through the through holes 3 and 3, and 5 is filled in the metal outer ring 1 to seal the metal outer ring 1 and the lead wires 4 and 4 in an airtight and insulated manner.

It is made of glass, and the lower surface is pressurized by a sealing jig to become a planar jig light surface, and the upper surface exposed to the through holes 3, 3 is a free surface that is not pressurized by the sealing jig. There is.

Then, as shown in Fig. 2, a spring support 6.6 is fixed to the lead wire 4.4, and this spring support 6.
．． A disk-shaped crystal resonator 7 is sandwiched between the rings 6 and 6, covered with a cap 8, and cold-press-welded to the metal outer ring 1.

As shown in FIG. 3, the metal outer ring 1 is made of soft metal suitable for cold pressure welding, such as copper 1a, and Kovar (Fe-Ni-Co alloy) lb, which can be sealed with glass 5. The clad plate is pressed so that the upper surface of the flange portion 9 which is overlapped with the cap 8 is made of copper 1a, and the inner surface in contact with the glass 5 is made of kovar 1b.

Further, a protrusion 10 is formed at a portion sized from the lower end of the long cylindrical inner surface of the metal outer ring 1, and the lower end of the glass 5 is aligned with this protrusion 10 to form a space 11.

Furthermore, the wall thickness of the long cylindrical metal outer ring 1 is set to t2 in a portion above the projection 10, and tl in a portion below the projection 10, which is smaller than the wall thickness t2 in the upper portion.

In the above configuration, a cap 8 is attached to the flange portion 9 of the metal outer ring 1.
When the flange portions of 1 are overlapped and cold welded, the metal outer ring 1 deforms inward due to the pressure welding stress.
This is to prevent cracks from occurring in the glass 5 due to this deformation stress.

That is, the projections 10 prevent the glass 5 from creeping down along the inner wall surface of the metal outer ring 1.

In addition, the space 11 has a large escape area due to the deformation of the metal outer ring 1.

Furthermore, by making the thickness of the metal outer ring 1 different between the upper and lower parts of the protrusion 10, the upper part of the protrusion 10 is difficult to deform due to pressure contact stress, and the lower part of the protrusion 10 is easily deformed, so that the contact stress is reduced to the glass 5. It is designed so that it does not absorb waves.

This type of airtight terminal is manufactured as follows.

That is, as shown in FIG. 4, a lower sealing jig 12 is prepared, which is made of graphite and has a protrusion 13 that fits into the metal outer ring 1 and lead wire insertion holes 14, 14.
A lead insertion hole 1 is formed on the protrusion 13 of the lower sealing jig 12.
A glass tablet 1°5 having a diameter of 6, 16 is placed, a metal outer ring 1 is placed on top of the glass tablet 15, and the lead wires 4, 4 are passed through the lead insertion holes 16, 16 of the glass tablet 15. and insert into the lead insertion holes 14, 14 of the lower sealing jig 12.

Finally, a lead insertion hole 18 made of graphite,
18 and the upper sealing jig 17 having spaces 19 and 19 around it, and insert the lead wires 4, 4 into the lead insertion hole 18.
, 18 to complete the assembly.

In this state, the whole is placed in a neutral or weakly reducing atmosphere for about 1
000° C. to melt the glass tablet 15, the glass 5 is fused to the metal outer ring 1 and the lead wire 4, and then cooled to solidify the glass 5.
A hermetic terminal having the structure shown in the figure and FIG. 2 is obtained.

By the way, in the airtight terminals shown in FIGS. 1 and 2, the through holes 3.3 formed in the top plate portion 2 of the metal outer ring 1 are perfectly circular, so that The distance I to the edge of the long cylindrical portion of the metal outer ring 1 is large, and voids 19 and 19 are provided in the portions of the upper sealing jig 17 corresponding to the above-mentioned through holes 3, 3. As a result of sealing the glass tablets 15 exposed in the holes 3 and 3 without applying pressure, air bubbles 20 are formed at the corners of the top plate part 2 and the long cylindrical part of the metal outer ring 1, as shown in FIG. is easily packed.

If air bubbles are packed inside the glass 5, the apparent volume of the glass 5 increases.

As is clear from FIG. 4, the glass tablet 15 is melted.

Then, a part of the molten glass flows into the minute gap between the through hole 3°3 of the metal outer ring 1, the inner surface of the elongated cylindrical part of the metal outer ring, the outer peripheral surface of the glass tablet 15, and the outer peripheral surface of the glass tablet 15. , these volumes are extremely small, and the apparent increase in molten glass due to the pack of air bubbles 20 is due to the fact that the upper surface of the glass is not pressurized by the upper sealing jig 17, as described above. Therefore, it is easy for the sushi to partially crawl up along the lead wires 4, 4, or to crawl down over the protrusion 10.

If the amount of glass creeping up along the lead wires 4, 4 is large, the distance m between the upper end of the lead wires 4, 4 and the upper end of the glass creeping portion becomes smaller, and the spring support 6.6
Spring support 6.
There is a risk that the crystal resonator 7 held between the caps 6 and 6 may come into contact with the cap 8.

Furthermore, if the glass creeps down over the protrusion 10, a crack will occur in the glass creeping part during cold pressure welding, and this crack will grow to the deep part i of the glass 5, causing airtightness deterioration.

On the other hand, if the volume of the glass tablet 15 is smaller than the specified value and air bubbles 20 are packed inside the glass 5, the sealing distance between the glass 5 and the metal outer ring 1 becomes smaller, as shown in FIG. Therefore, airtight leakage is likely to occur.

'There are various problems when the through holes 3, 3 are perfectly circular in shape.

This invention was proposed to solve these problems, and is characterized by having an oval shaped through hole.

An embodiment of this invention will be described below with reference to the drawings.

FIG. 7 shows a plan view of the airtight terminal of this invention, and FIG. 8 shows a cross-sectional view taken along the line ■--■ in FIG.

In the figure, the structure is the same as the conventional example shown in FIGS. 1 to 3 except for the following points, and the same parts are given the same reference numerals and the explanation thereof will be omitted.

A feature of this embodiment is that the through holes 30, 30 formed near both longitudinal ends of the top plate portion 2 of the metal outer ring 1 are formed in an elliptical shape whose longitudinal direction coincides with the longitudinal direction of the metal outer ring 1. Therefore, the distance dimension 1' from the edge of the through hole 30, 30 to the edge of the elongated cylindrical portion of the metal outer ring 1 is much smaller than that of the conventional metal ring 1.

Therefore, according to the above configuration, the top plate portion 2 of the metal outer ring 1
As shown in FIG. 5 or 6, no air bubbles 20 are packed in the corners between the inner wall of the long cylindrical portion and the inner wall of the long cylindrical portion, and this is caused by the air bubbles being packed inside the glass 5. , Glass creeping and protrusions along the lead wire 4°4 1
No more creeping down than 0, spring support 6
．． The crystal oscillator 7 held between the caps 6 and 6 may come into contact with the cap 8, cracks may occur in the glass 5 during cold welding and the airtightness may deteriorate, or air bubbles may cause the glass 5 and the metal outer ring 1 to
There is no possibility of hermetic leakage due to the shortening of the sealing distance.

Although the above embodiment describes a case in which this invention is applied to a cold pressure welding type airtight terminal, the same applies to an airtight terminal in which the flange part of the cap is overlapped with the flange part of the metal outer ring and resistance welded. Since the metal outer ring is easily deformed by stress during resistance welding, a similar structure can be used.

However, it goes without saying that the metal outer ring 1 does not need to be composed of a clad plate of copper 1a and Kovar 1b.

As described above, in this invention, the through hole drilled in the top plate of the metal outer ring is made into an oval shape, so the distance from the edge of the through hole to the edge of the elongated cylindrical part is extremely small. This has the effect that air bubbles are not packed in the corners of the top plate portion and the long cylindrical portion, and a high-quality airtight terminal with good airtightness can be obtained.

[Brief explanation of the drawing]

Figure 1 is a plan view of the airtight terminal which is the background of this invention, Figure 2
The figure is a sectional view taken along the line ■-■ in Figure 1, Figure 3 is an enlarged sectional view of the main part of Figure 2, and Figure 4 is for explaining the manufacturing method of the airtight terminal in Figures 1 and 2. Figures 5 and 6 are cross-sectional views of essential parts showing defects that occur in conventional hermetic terminals, and Figure 7 is an airtight diagram of an embodiment of this invention. Terminal plan view, Figure 8 is Figure 7
It is a sectional view taken along the line ■-■ in the figure. 1...Metal outer ring, 2...Top plate part, 4,
4...Lead wire, 5...Glass, 30
．． 30...Through hole.

Claims (1)

[Claim for Utility Model Registration] A through hole is drilled near both ends of the top plate in the longitudinal direction of the inverted boat-shaped metal outer ring, and a lead wire is inserted through the through hole so that the inside of the metal outer ring is exposed to the lower surface. In an airtight terminal sealed with glass, in which the upper surface exposed to the through hole is a free surface and is the surface that contacts the sealing jig, An airtight terminal characterized by its circular shape.