JPS598921B2 - Manufacturing method of glass mirror base - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a glass mirror substrate used in a mirror condenser type light bulb device.

For example, the Miller condenser type light bulb device is
As introduced in Japanese Patent No. 12219, the light bulb base is fixed to the light bulb base receiving part of the mirror with adhesive, and the light emitting center of the light bulb, e.g. The position of the filament is fixed, so it is used in projectors and other devices as a so-called ``focusing-free'' light bulb device.

The manufacturing method of the glass mirror base used in this light bulb device is the same as when manufacturing a regular bottomed glass molded product, in which the mirror surface forming part and the bottomed bulb base receiving part are integrated into a mirror. The mirror base was manufactured by creating a base prototype, cutting the light bulb base receiving part from the middle, and cutting out the bottom. However, during this cutting process, a "chip" occurred around the outer periphery of the cut, and this "chip" was used as the starting point. As a result, there have been accidents where cracks and cracks occur during use of light bulb devices.

In the present application, even if there is this "chip", there are enough "cracks" and "
The purpose is to provide a method for manufacturing a glass mirror base that prevents the occurrence of cracks, and its characteristics include the step of creating a mirror base prototype so that a part of the taper is formed on the outer peripheral surface of the bulb base receiving part. and a step of cutting the master model at a portion of the taper.

This will be explained below along with the drawings.

Figure 1 A, C and C are explanatory diagrams of the conventional manufacturing method;
The figures show an enlarged view of the cut section shown in FIG. 1C, FIG.

In FIG. 1A, 1a and 1b are a pair of molds, 2 is a molten glass member, the opening in the figure is a cooled and solidified glass mirror base model, 3 is a mirror surface forming part, and 4 is a mold. is the light bulb base receiving part, 5 is the bottom part, and in the same figure 8,
The bottom part 5 is cut away and a cutting kerf 6 is formed.

At this time, since the outer circumferential surface of the receiving portion 4 is flat in the mirror axis direction, a relatively large "chip" 7 is generated on the outer circumference of the end surface of the cutting cut 6, as shown in FIG. When the light bulb device is in use, or when the light bulb device is in use, it is moved along the surface of the receiving part 40 from this "crack" 7 in the axial direction.
However, in the present application, as shown in FIG. 3, a "tapered portion 8" is provided in the receiving part forming area of one side 1b of the mold for making the base model, and the light bulb is A tapered portion 9 is formed on the outer peripheral surface of the base receiving portion.

Then, the prototype is cut at the position of this taper part 9. In that case, the cutting cut 6 is as shown in FIG.
Even if a "chip" occurs, it is small and is located in the tapered part 9, so that during assembly or use of the light bulb device, a "crack" that runs along the surface of the light bulb base receiving part 40 in the direction of the mirror axis will occur. "Cracks" do not occur.

The reason why the above effects can be obtained is not fully explained theoretically, but in reality, according to the conventional method, the occurrence rate of "chips" is 5 times higher, and the occurrence of "cracks" or "breaks" is lower than 5 times. The rate of accidents used to be 2 times, but according to the method of the present invention, the occurrence rate of "chips" is 1 times, and the incidence of "cracks" or "breaks" is 0.1 times, which significantly reduces the accident rate. It was confirmed that the amount decreased.

From this fact, the reason why the effects of the present invention can be obtained is as follows: (1) The mold has a step-shaped taper part 8 corresponding to the taper part 9, and this taper part B and the part above it are Because the thickness is different from the space, when molten glass is injected into the mold, the flow of molten glass will not be uniform and continuous in the direction of the mirror axis (vertical direction in the drawing). , and ■ In the process of cooling the injected molten glass, there is a difference in the degree of cooling between the glass part that becomes the tapered part 9 and the glass part with a uniform thickness above it, so that the glass part is not uniformly thick. Because of this, in the manufactured glass mirror base model, the structure of the glass is poor between the taper part 9 and the part of the bulb base receiving part 4 above it. The glass structure is not uniformly continuous in the mirror axis direction of the mirror, but rather uniformly continuous in the circumferential direction, in other words, the glass structure is highly continuous in the circumferential direction.

On the other hand, the base model has a taper part 9 of the bulb base receiving part.
However, the thickness of the tapered portion 9 changes in the mirror axis direction of the mirror, and the thickness of the tapered portion 9 changes in the mirror axis direction.
Since the thickness increases as it approaches
Chips are less likely to occur in the portion where the thickness is greater than the cut edge in the radial direction, that is, the portion of the cut cut 6 located above in the figure.
Even if it does occur, it will only result in small "chips" in the radial direction.

As a result, according to the method of the present invention, the occurrence of "chips" is small, and even when they do occur, only small ones extending in the radial direction are generated as shown in FIG. ”, especially in the mirror axis direction, “cracks” and “
It is thought that this makes it difficult for cracks to occur.

On the other hand, in the conventional method, the structure of the glass in the bulb base receiving part of the base mold is highly continuous in the direction of the axis of the mirror, and the thickness is uniform. Due to the influence,
"chips" are likely to occur and are large, and
It is thought that the incidence of accidents is high because cracks and cracks are particularly likely to occur and grow in the direction of the mirror axis.

As described above in detail, the method for manufacturing a glass mirror substrate of the present application has the advantage of being able to provide a glass mirror substrate with significantly fewer accidents by just slightly changing the conventional manufacturing method.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the conventional manufacturing method, FIG. 3 is an explanatory diagram of the manufacturing method of the present application, and FIGS. 2 and 4 are enlarged views of cut sections, respectively. 1 In the figure, 1a and 1b are a pair of molds, 2 is a molten glass member, 3 is a mirror surface forming part, 4 is a light bulb base receiving part, 7 is a "chip", and 9 is a part of a taper.

Claims (1)

[Claims] 1. In a method for manufacturing a glass mirror base body in which a light bulb base receiving part and a mirror surface forming part are integrally formed, the outer peripheral surface of the receiving part has a tapered part whose thickness increases as it approaches the mirror surface forming part. 1. A method for manufacturing a glass mirror substrate, comprising the steps of: manufacturing a glass mirror substrate prototype so as to form a mirror substrate; and cutting the prototype at a portion of a front taper.