JPH0414938Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a diode, particularly a diode using a glass package.

Figure 1 shows a conventional leadless type diode, where 1 is a glass cylindrical package, 2 is an upper electrode, and 3 is a lower electrode (both made of dumet wire). Head 4A,
5A and cylindrical portions 4B and 5B. 6
is a diode chip. This type of diode is manufactured as follows. First, insert the lower edge of the package 1 into the cylindrical portion 5B of the lower electrode 3 from above until it contacts the surface 7 of the head 5A, then drop the diode chip 6 into the package 1 and place it on the top surface of the cylindrical portion 5B. let Thereafter, the cylindrical portion 4B of the upper electrode 2 is fitted into the upper end of the package 1. The lower surface of the cylindrical portion 4B is brought into contact with the diode chip 6. At this time, a gap 8 is formed between the upper end 1A of the package 1 and the lower surface of the head 4A. Due to the existence of this gap 8, the weight of the upper electrode 2 acts, and the upper electrode 2 comes into contact with the diode chip 6 with an appropriate pressure. After that, put it in a heating oven and heat it all up. By this heating, the cylindrical portions 4B, 5B, the inner surface of the package 1, the lower end of the package 1, and the surface 7 of the head 5A are fused to each other and are airtightly integrated.

By the way, in such a manufacturing process, the electrodes 2 and 3 and the package 1 expand and contract during the heating stage. In this case, the expansion and contraction along the axial direction of the package 1 is caused by the sliding between each cylindrical part 4B, 5B and the inner surface of the package 1, even if there is a difference in expansion and contraction between the package 1 and each electrode 2, 3. Since the above-mentioned difference is absorbed by the operating force, no particular problem arises. However, the difference in expansion and contraction along the radial direction of the package 1 is hardly absorbed because there is no room for the above-mentioned sliding action. Therefore, (distortion) may occur at the interface between the lower end of the package 1 and the surface 7 of the head 5A. If such a large strain occurs, a crack will appear at the lower end of the package 1. In actual practice, if the difference in diameter between the cylindrical portion 5B and the head 5A (and therefore the radial width of the surface 7) is about 0.6 to 0.7 mm, there is almost no problem, but if this exceeds 1.1 mm, the package cage 1 may crack. begins to occur. Note that the upper end of the package cage 1 does not come into contact with the head 4A due to the existence of the gap 8, so there is no problem.

In order to prevent the package 1 from cracking as described above, a plurality of protrusions separated in the circumferential direction are formed at the base end of the cylindrical portion 5B of the lower electrode 3, and the lower end of the package 1 rests on the surface of the protrusions. has been proposed (see Japanese Unexamined Patent Publication No. 59-43558).

According to this, the contact area between the lower end of the package cage 1 and the head 5A of the lower electrode 3 is reduced, which is convenient.
Since it does not extend to the outer circumferential edge, and its contact area is planar, smooth heat absorption is not possible during heating for fusion, and cracks develop in the circumferential direction. come to arise.

The purpose of this invention is to prevent the occurrence of cracks in the package during heating to fuse the package and electrode in a diode equipped with a glass package.

As mentioned above, cracks occur in the package because the larger the area of fusion between the lower end of the package and the head of the lower electrode, the more likely they are to occur. By reducing the area, the occurrence of the cracks is prevented.

An embodiment of this invention will be explained with reference to FIG.
As can be understood from the same figure, of both the upper and lower electrodes 2 and 3 inserted into the upper and lower ends of the package 1 in the axial direction, the head 5A of the lower electrode 3 is A plurality of protrusions 9 are provided at approximately equal intervals so as to extend radially up to the outer peripheral end of 5A.
This protrusion 9 is preferably formed at the same time as the lower electrode 3 is manufactured.

As shown in FIG. 3, the protrusion 9 shown in FIG. 2 is a protrusion with a triangular cross section.

The manufacturing process of the diode is the same as in the conventional case described above. However, the lower end of the package cage 1 has a protrusion 9
Since it rests on the top surface of the head 5A, it does not touch the entire surface of the head 5A, but in a straight line.

When heated in this state, since the protrusion 9 is formed to extend to the outer peripheral end of the head 5A, smooth heat absorption is possible, and "cracks" occur in the straight part during fusion. Even if this happens, it will stop its occurrence locally and will not develop in the circumferential direction and cause "cracks."

Note that, as in the conventional case, the circumferential surfaces of the cylindrical portions 4B and 5B and the inner surface of the package 1 are fused and integrated in an airtight manner.

In another embodiment shown in FIG. 4, the protrusion 9 is configured in the shape of a protrusion with a hemispherical cross section. Even in this configuration, the lower end of the package cage 1 and the surface 7 of the head 5A of the lower electrode 3 come into contact with each other in a straight line via the top surface of the protrusion 9.

As detailed above, this invention has the effect of easily and reliably preventing the occurrence of cracks in the package during heating during fusion with the electrode in a diode equipped with a glass package. play.

[Brief explanation of drawings]

Fig. 1 is a sectional view of a conventional example, Fig. 2 is a sectional view showing an embodiment of this invention, Fig. 3 A and B are a plan view and side view of the lower electrode, and Fig. 4 A and B are another embodiment. FIG. 7 is a plan view and a side view of a lower electrode in an example. DESCRIPTION OF SYMBOLS 1...Package, 2...Upper electrode, 3...Lower electrode, 6...Diode chip, 7...Surface, 9...
...projection.

Claims (1)

[Scope of utility model registration request] An upper electrode and a lower electrode are inserted into the upper and lower ends in the axial direction of a cylindrical package made of glass, and a diode chip is sandwiched between the upper and lower electrodes, and both electrodes are inserted into the tube inserted into the inside of the package. and a head part connected to the cylindrical part and having a surface facing the end surface of the package, and the surface of the head part of the lower electrode has a plurality of radially extending from the base end of the cylindrical part to the outer peripheral end of the head part. 1. A diode characterized in that a protrusion is provided, and the protrusion has a shape in which a portion in contact with an end surface of the package is a straight line.