JPS6160594B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing an airtight window in which a transparent glass is hermetically sealed within a metal outer ring, and more particularly to a method for manufacturing a lens cap for a small electronic component such as an optical semiconductor device.

The light emitting diode has the structure shown in FIGS. 1 and 2, for example. In the figure, reference numeral 1 denotes an airtight terminal stem, which has a flat head 5 inserted into a cylindrical metal outer ring 2 made of Kovar (iron, nickel, and cobalt alloy) through a black borosilicate glass 3. The lead wire 4 is hermetically and insulatively sealed. 6 is a light emitting diode pellet,
It is electrically and mechanically fixed onto the head 5 of the lead wire 4 by solder, and its upper surface electrode is connected to the inner surface of the metal outer ring 2 via a thin wire 7 made of gold, aluminum, or the like. Reference numeral 8 designates a lens cap, in which a transparent borosilicate glass 10 is hermetically sealed within a metal outer ring 9 made of Kovar. It is fixed to the upper end of the metal outer ring 2 with a pad 11, and the light emitting diode pellet 6 is hermetically sealed.

Since the lens cap 8 has a very small outer diameter of, for example, about 2 mm, a transparent glass disk is placed inside the metal outer ring 2 like a general airtight window for a refrigerator. The working temperature is about
Glass cannot be sealed to metal outer ring 2 by heating at 1000°C. Therefore, it is manufactured as follows. First, as shown in FIG. 3, a large-diameter recess 13 into which the metal outer ring 9 can be fitted is formed in a sealing jig 12 made of graphite, and a recess 13 is formed on the bottom surface of this recess 13.
A recess 14 is provided concentrically with the recess 13 and has a smaller diameter than the recess 13, and an oxide film 15 is provided only on the inner surface of the recess 13.
The metal outer ring 9 formed with the metal outer ring 9 is inserted and arranged. The metal outer ring 9 with the oxide film 15 formed only on the inner surface is manufactured by, for example, forming the oxide film 15 on the entire surface of the metal outer ring 9, and then barreling the metal outer ring 9 together with a stone having a diameter larger than its inner diameter. The metal outer ring 9 can be manufactured by rotating the barrel and polishing off the oxide film on the outer peripheral surface and upper and lower end surfaces of the metal outer ring 9 using stones or other metal outer rings 9. A transparent glass disk 10a is placed on the metal outer ring 9 and heated at about 1000° C., which is the working temperature of the transparent glass disk 10a, in a neutral or weakly reducing atmosphere. Then, the transparent glass disk 10a softens and melts, and as shown in FIG. When wet, it is fused to the inner surface of the metal outer ring 9. At this time, if the amount of the molten glass 10b is set appropriately, the molten glass 10b will float from the sealing jig 12 and become concave on both the upper and lower surfaces due to surface tension, as shown in FIG. . Therefore,
When cooled in this state, a lens cap 8 as shown in FIGS. 1 and 2 is obtained.

By the way, in the lens cap 8 manufactured as described above, as shown in FIG. 6 and FIG. This reduces the luminous flux divergence of the light emitting diode.

Therefore, the main object of the present invention is to provide an airtight window such as a lens cap that is free of brownish films on both the upper and lower surfaces of the glass and has high transparency.

In summary, this invention involves heating the glass inside the metal outer ring at working temperature and sealing it airtight, then applying acid treatment to remove the film on the glass surface, and then heating the glass to a temperature that is above the softening point of the glass and below the working temperature. The glass surface is also characterized by being reheated at a temperature lower than 100°C to make the glass surface smooth and free.

The above-mentioned objects and other objects and features of this invention will become more apparent from the detailed description given below with reference to the drawings.

First, before giving a detailed explanation of the present invention, let us consider the reason for the formation of the brownish-brown film.
The metal outer ring 9 has a cylindrical shape, and is generally manufactured by cutting a long pipe member with predetermined inner and outer diameters into appropriate dimensions. However, when manufacturing pipes, lubricants such as molybdenum sulfide and phosphate solutions are used, and the lubricants are strongly rubbed against the surface of the pipe member due to the strong molding pressure during pipe manufacturing. Furthermore, this lubricant not only adheres to the inner and outer surfaces of the pipe material, but also penetrates into the grain boundaries of Kovar. For this reason, even if this pipe material is cut to produce the metal outer ring 9 and the surface is cleaned by pretreatment such as pickling, the lubricant that has entered the grain boundaries remains without being removed. ing. Therefore, preliminary oxidation is performed to form an oxide film 15 on the metal outer ring 9, and approximately
When glass-sealing is performed by heating to 1000° C., the lubricant that has entered the grain boundaries of the metal outer ring 9 oozes out from both the inner and outer surfaces of the metal outer ring 9 due to the heating. Since this oozing lubricant is insoluble in the molten glass 10b and has a lower specific gravity than the molten glass 10b, it is thought that it flows in a floating state on both the upper and lower surfaces of the molten glass 10b, forming a brownish-brown film 16. . In severe cases, this film 16 adheres to the entire top and bottom surfaces of the glass 10.

It has been confirmed that the film 16 can be removed by washing with an acid solution such as hydrofluoric acid, but after the film 16 is removed, the upper and lower surfaces of the glass 10 become finely uneven surfaces due to the etching action of the acid solution, and the glass surface becomes A thin white film appears on the glass 1.
It was found that the transparency of 0 was reduced.

Therefore, in order to make the fine irregularities on the glass surface smooth by remelting the glass 10 by reheating,
When the glass 10 was reheated under the same conditions as the above-mentioned sealing conditions, that is, at approximately 1000° C., which is the working temperature of the glass 10, a brown film 16 was again formed on both the upper and lower surfaces of the glass 10. This is also because the brown film 16 is formed on the peripheral edges of both the upper and lower surfaces of the glass 10, indicating that the lubricant that had entered the grain boundaries of the metal outer ring 9 oozes out again due to reheating. This can be well explained using the theory that

This invention has been proposed based on the above-mentioned phenomenon and investigation of its causes, and one embodiment thereof will be described below with reference to FIGS. 8 to 12. First, the 8th
As shown in the figure, in the recess 13 of the sealing jig 12,
A metal outer ring 9 with an oxide film 15 formed only on the inner surface is arranged, and a transparent glass disk 10a is placed on this metal outer ring 9.
and heat the whole thing to about 1000℃ in a neutral or weakly reducing atmosphere. Then, as explained in FIGS. 3 to 5, the transparent glass disk 10a
is melted and sealed to the metal outer ring 9 to obtain a lens cap 8 as shown in FIG. A brown film 16 is formed on both the upper and lower surfaces of the glass 10 of this lens cap 88. Next, the lens cap 8 is immersed in an acid solution, for example, a mixed acid of hydrofluoric acid and sulfuric acid, for about 1 to 5 minutes to remove the film 16 formed on the surface of the glass 10. At this time, the surface of the glass 10 is also removed by the etching action of the acid solution, so that both the upper and lower surfaces of the glass 10 become finely uneven surfaces 17, as shown in FIG.
Glass 1 appears as if a thin white curtain is covering the entire surface.
0 transparency decreases. Therefore, as shown in FIG. 11, this lens cap 8 is placed again in the recess 13 of the sealing jig 12, and the lens cap 8 is placed in a neutral or weakly reducing atmosphere at a temperature equal to or higher than the melting point of the glass 10. Temperature lower than temperature, e.g. 700-900℃
Reheat. Then, the convex portions of the finely uneven surfaces 17 on both the upper and lower surfaces of the glass 10 melt and fill the concave portions, so that both the upper and lower surfaces of the glass 10 become smooth free surfaces 18, as shown in FIG.
The transparency becomes very high.

Here, if the reheating temperature is lower than the softening point of the glass 10, the finely uneven surface 17 of the glass 10 cannot be made into a smooth free surface 18, and the reheating temperature is lower than the working temperature.
At a temperature lower than 100°C, the entire glass 10 is completely remelted, and the lubricant, etc. that had entered the grain boundaries of the metal outer ring 9 ooze out into the molten glass 10c, causing the surface of the molten glass 10b to ooze out. As a result, a brown film 16 is generated again. Therefore, the reheating temperature is limited to a temperature that is higher than the softening point of the glass 10 and lower than the working temperature by 100° C. or more.

Although the above embodiments have been described with respect to lens caps for light emitting diodes, they can be applied to the manufacture of airtight windows such as lens caps for other optical semiconductor devices.

As described above, this invention involves the steps of cutting a long metal pipe member to produce a metal outer ring, sealing the glass inside the metal outer ring airtight at working temperature, and applying acid treatment to the glass surface. After removing dirt from the glass, it is reheated at a temperature above the softening point of the glass and at least 100 degrees Celsius below the working temperature, which allows the production of airtight windows such as lens caps with extremely high glass transparency. play.

[Brief explanation of the drawing]

Figure 1 is a plan view of an example of a light emitting diode, Figure 2 is a plan view of an example of a light emitting diode.
The figure is a cross-sectional view taken along the - line in Figure 1, Figures 3 to 5 are cross-sectional views at various stages to explain the conventional method of manufacturing a lens cap, and Figure 6 is a cross-sectional view of the lens cap manufactured by the conventional method. FIG. 7 is a sectional view taken along the - line in FIG. 6, and FIGS. 8 to 12 are sectional views at each stage of an embodiment of manufacturing a lens cap according to the present invention. 8... Airtight window (lens cap), 9... Metal outer ring, 10... Glass, 10a... Transparent glass disk, 10b... Molten glass, 12... Sealing jig,
16...brown film, 17...fine uneven surface, 1
8...Smooth free surface.

Claims (1)

[Claims] 1. A process of cutting a long metal pipe member to produce a metal outer ring, a process of airtightly sealing glass inside the metal outer ring at working temperature, and acid treatment to produce a metal outer ring. The process of removing surface dirt and the temperature above the softening point of glass and 100℃ below the working temperature.
A method for manufacturing an airtight window, comprising a step of reheating at a temperature lower than ℃. 2. The method of manufacturing an airtight window according to claim 1, wherein the metal outer ring has an oxide film formed only on its inner surface. 3. The method of manufacturing an airtight window according to claim 1, wherein the glass sealing step is carried out with a transparent glass disk placed on a metal outer ring.