JPH01207958A - Dhd type glass sealed diode - Google Patents

Abstract

PURPOSE:To keep a glass tube from being damaged by mechanical and thermal stresses, by coating extensively the external surface of a glass tube of a diode further with a resin film. CONSTITUTION:A pair of slag leads 1 are disposed in series in such a way that one of parts having large diameters corresponds to the other part of them and a diode chip consisting of a semiconductor element 2 which has electrodes on both faces is interposed at an interval between the large diameter parts of the slag leads 1 which correspond each other by bringing the above chip into contact with the electrodes. Then, the semiconductor element 2 and the large diameter parts of slag leads are kept airtight and are sealed by a glass tube and further, the external surface of its glass tube is coated extensively with a resin film 4. Thus, the resin film 4 coating the whole external surface of the glass tube 3 acts as a buffer with respect to mechanical, thermal stresses caused by outside conditions. Then, the resin film protects the glass tube 3 from exerting stress directly on the glass tube 3 and prevents the development of a crack and split.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to I) an HD type glass-sealed diode.

[Conventional technology]

DHD-type glass-sealed diodes (hereinafter simply referred to as diodes) are generally made by arranging two lead wires, each of which has a large diameter at one end called a slug lead, in series with the large diameter portions corresponding to each other. A semiconductor body having electrodes on both sides is sandwiched between the large-diameter end faces of the slug lead, and the semiconductor body and the large-diameter part of the slug lead are air-aired together using a glass tube. A hermetically sealed structure is known, and the outer surface of this glass tube is partially coated with resin in a thin ring shape to display the diode's polarity 2 quality, loft, etc.

[Problem to be solved by the invention]

However, when a diode with this structure is mounted on a printed circuit board, cracks may occur in the glass tube due to mechanical stress during insertion into the board and thermal stress during soldering to secure it to the board. There was a drawback that the glass tube could break.

SUMMARY OF THE INVENTION It is an object of the present invention to eliminate the above-mentioned drawbacks and to provide a diode whose glass tube is less susceptible to damage even when subjected to mechanical and thermal stress.

[Means to solve the problem]

In order to achieve the above purpose, in the present invention, the corresponding portion placed in series is on both sides in which one pair of slugged, which is large diameter, and an electrode between these sluggish correspondence. In a device consisting of a semiconductor element having an electrode and a glass tube that hermetically seals the semiconductor element and the large diameter portion of the slack IJ, the entire outer surface of the glass tube is further coated with a resin film. Structure.

[Effect]

The resin film that covers the entire outer surface of the glass tube acts as a buffer against external mechanical stress and thermal stress, protecting the glass tube from direct contact with the stress and preventing cracks. Prevents cracking.

〔Example〕

FIG. 1 shows an embodiment of a guioto according to the present invention. FIG.
A diode chip, which is a semiconductor body 2 having electrodes on both sides, is sandwiched between corresponding large diameter portions of a slug lead 1 with the electrodes in contact with each other, and the semiconductor body 2 and the large diameter portions of the slug lead 1 are connected to a glass tube. 3, and the entire outer surface of the glass tube 3 is covered with a resin film 4. The resin film 4 is formed, for example, by applying Epoquine resin ink to the outer surface of the glass tube to a thickness of several tens of micrometers. Figure 1(b) shows the first
This is a sectional view taken along the line A-A in Figure (a), in which a glass tube 3 is in close contact with the large diameter portion of the slag lead 1, and a resin film 4 covers the outer surface of the glass tube.

FIG. 2 shows another embodiment, in which the same parts as in FIG. 1 are given the same reference numerals. FIG. 2(a) is a side view of the Gouioto, showing the resin film 4 covering the outer surface of the glass tube.
A link-shaped resin film 5 is further formed on the outer surface of the quioto.
Quality, lot, etc. can be displayed. Figure 2 (b
) shows a sectional view taken along line BB in FIG. 2(a), showing a state in which the resin film 5 further covers the entire circumference of the resin film 4.

For comparison, a diode in which the outer surface of the glass tube is not coated with a resin film and a diode in which the outer surface of the glass tube is partially coated with a ring-shaped resin film (approximately 1/3 of the outer surface in the longitudinal direction) are used. The strength against mechanical stress was investigated for the fully resin-coated diode D1 of the example, the partially resin-coated diode D2 of the comparative example, and the diode D3 not coated with the resin film. As shown in FIG. 3(a), the diode 6 was placed on an iron stand 7, and an iron block 8 weighing 100 g was dropped from above to measure the height h at which the glass tube began to break. The measurement results are shown in FIG. 3(b). The type of diode is plotted on the horizontal axis of FIG. 3(b), and the vertical axis represents the height h at which the glass tube begins to break. It can be seen from FIG. 3(b) that the strength against mechanical stress of the diode D1 is improved by about three times at the drop height h compared to the diode D2 or the diode D3.

Next, the strength of these diodes against thermal stress was investigated. As shown in FIG. 4(a), the diode 6 was immersed into the melted solder 10 filled in the solder bath 9, and the solder temperature at which the glass tube began to break was determined. The measurement results are shown in FIG. 4(b). From Figure 4(b), diode D1 has a soldering temperature of about 1100 cle compared to diode D2 or diode D3.
It can be seen that the strength against thermal stress is improved to some extent.

Similar measurements were performed on diodes of other examples in which a resin film was further provided in a link-like manner on top of the resin film, and the results showed that the same mechanical stress as that of the diode of one example was observed.
Improvement in strength against thermal stress was observed.

〔Effect of the invention〕

According to the present invention, the entire outer surface of the glass tube of the DHD type glass-sealed diode is further coated with a resin film. With this structure, the resin film acts as a buffer against external mechanical stress and thermal stress, making the glass tube less likely to be damaged, and reducing mechanical stress and thermal stress compared to conventional quaiodes. It is possible to obtain a DHD type glass-sealed diode with greatly improved strength against stress, and it is possible to dramatically reduce defects that occur when the diode is mounted on a printed circuit board.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of the present invention; FIG. 1(a) is a cross-sectional view, and FIG. 1(b) is a cross-sectional view taken along the line AA in FIG. 1(a). Fig. 2 shows another embodiment of the present invention, Fig. 2(a) is a side view, and Fig. 2(b) is a line B-B of Fig. 2(a).
FIG. FIG. 3(a) is an explanatory diagram of a method for measuring strength against mechanical stress, and FIG. 3(b) is a diagram showing the measurement results. FIG. 4(a) is an explanatory diagram of a method for measuring strength against thermal stress, and FIG. 4(b) is a diagram showing the measurement results. 1 Slag lead, 2 Semiconductor element, 3 Gala (o) th'°C) 4 Figure

Claims (1)

[Claims] (1) A pair of slug leads whose corresponding parts are arranged in series with a large diameter, a semiconductor body having electrodes on both sides sandwiched between the corresponding surfaces of these slag leads with electrodes in contact with each other, and these semiconductor elements. 1. A DHD type glass-sealed diode comprising a glass tube hermetically sealing a large diameter portion of a slug lead and a glass tube, the entire outer surface of said glass tube being further coated with a resin film.