JP2009173464A - Method for producing glass molded body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a thick lens high in precision and small in diameter. <P>SOLUTION: In this method, fthe molded body having a predetermined shape is produced by using a molding mold at least composed of a lower mold and an upper mold, arranging two or more glass stocks at the surface of the molding face of the lower mold, heating the glass molding stocks and at least the lower mold to the press moldable temperature of the glass stocks, and press-molding the glass stocks by the molding mold, thereby integrally joinning the glass stocks. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to a method for producing a glass molded body requiring high shape accuracy by hot forming using a mold having a cavity corresponding to the shape. In particular, the present invention relates to a glass molded body suitable for molding of a lens having a small diameter and a shape close to a rod having a thickness larger than the diameter, and a method for manufacturing the same. The field of manufacturing lenses with irregular shapes that are difficult to achieve with normal hot forming methods, especially high-precision small-diameter and thick lenses that do not require centering.

Since glass can be hot-molded, various methods have been proposed for molding a lens having a desired shape by heating using a mold. Recently, a method of directly manufacturing a lens by processing a surface of a mold into a highly accurate mirror surface and performing hot molding has been put into practical use. Since this method can eliminate processing steps such as grinding and polishing, it not only leads to cost reduction, but also aspherical lenses can be easily manufactured. By using these lenses, the number of lenses can be greatly reduced. Contributes greatly to miniaturization.

Japanese Patent Laid-Open No. 2001-48555 has already proposed a technique for producing a glass molded body having an irregular shape that is difficult to obtain by a normal hot forming method. However, the technique disclosed here is aimed at obtaining a glass molded body having an irregular shape such as a positioning member such as a thin optical fiber fixing member having a small aspect ratio and a large aspect ratio. The present invention relates to the production of a glass molded body that is required. On the other hand, an object of the present invention is to provide a method of manufacturing a lens having a small diameter and a thickness that does not require a centering process, and the required accuracy is not a weight accuracy but a shape accuracy. There is a big difference.

As described above, the problem to be solved by the present invention is, first of all, an irregular shape that is difficult to obtain by a normal hot forming method, in particular, a high-precision small-diameter and thick lens that does not require a centering process. It is to provide a method of manufacturing. In general, the centering operation of a glass molded body such as a lens having a small diameter and a thick lens (around φ1) involves technically difficult processes and increases the processing cost. For example, a grindstone pressing operation by a centering operation on such a glass molded body tends to cause the glass molded body to collapse. It is important that the centering work of the small-diameter lens (around φ1) eliminates secondary processing such as technical work.

By the way, it is extremely difficult to hot mold a glass molded body such as a thick small-diameter lens. When hot working glass, it is common to set the mold temperature below the glass transition temperature in order to prevent the glass from fusing to the mold, but especially when the molded product is small, contact the mold. In order to do so, it is cooled rapidly and solidifies before the glass is deformed. Depending on the shape, it becomes difficult to insert the glass material before molding into the mold.

Two or more glass materials are arranged on the molding surface of the lower mold using a mold composed of at least a lower mold and an upper mold, and the glass material and at least the lower mold are brought to a temperature at which the glass material can be press-molded. In the method of manufacturing a glass molded body having a predetermined shape by deforming and integrating the glass by press-molding the heated glass material with the molding die, A glass molded body having a highly accurate shape is obtained by adjusting.
As means for solving the problem, at least two glass materials are arranged on the molding surface of the lower mold using a molding die composed of at least a lower mold and an upper mold, and the glass material and at least the lower mold are made of glass. In a method for producing a glass molded body of a predetermined shape by heating up to a temperature at which the material can be press-molded, press-molding the heated glass material with the molding die, deforming and integrating the glass, It is a method for producing a glass molded body characterized in that a glass molded body having a highly accurate shape is obtained by adjusting the volume of the voids in the non-fused portion.
When a large amount of glass material is inserted into the mold, it is possible to keep the shape and dimensions accurately constant by reducing the volume of the gap generated between the materials.

According to the present invention, a small-diameter lens (for example, around φ1) can be easily obtained by the hot molding method, so that the centering work can be omitted and the unit cost of processing caused by technically difficult processes. It is possible to avoid the rise of.
The grindstone pressing operation by the centering operation on the glass molded body tends to cause the glass molded body to collapse. The centering operation of the small-diameter lens (around φ1) is important to eliminate the secondary processing such as the technical centering operation.

As one of the embodiments of the present invention, as a means for adjusting the gap of the non-fused portion in the above manufacturing method, the glass molding is characterized in that the total volume of the glass material is made smaller than the volume of the mold cavity. It is a manufacturing method of a body. By making the total volume of the glass material smaller than the volume of the cavity of the mold after the mold is pressed, the above-described gap can be surely formed.

In another embodiment of the present invention, a stopper is provided on at least one of the upper die and the lower die as a means for adjusting the volume of the gap in the non-fused portion, so that the upper and lower portions are fixed at predetermined positions during pressing. This is possible by fixing the mold. That is, it becomes possible to obtain a glass molded body with high dimensional accuracy by accurately determining the positions of the upper and lower molds after pressing. And since the total volume of the glass material is made smaller than the volume of the cavity of the mold after the mold is pressed, excess glass does not overflow from the mold.

Hereinafter, the present invention will be described based on examples. The present example is a molding example of a molded body in which the molded body becomes a rod lens for optical communication. FIG. 1 is a perspective view of a shape 10 of a general communication rod lens, which has a lens surface 11. FIG. 2 is a perspective view in the case of being molded according to the present invention, using three glass materials 4.

The glass material used in the examples was a dropping glass sphere obtained by dropping molten glass. The radius of the glass sphere is 1.25 mm. Here, the total volume when three pieces are used is 3.066 mm 3, and the volume of the cavity when the upper and lower molds are fixed by the stopper 6 is 3.189 mm 3.

FIG. 3 is a longitudinal sectional view showing a mold and its configuration when producing a molded body in FIG. 3. In the figure, a lower mold 2 is inserted into the body mold 1, and a space (cavity) into which a molded body material 4 is inserted, and an upper mold 3 are inserted from above. FIG. 4 is a detailed longitudinal sectional view of the cavity space (5), and shows a state in which three glass materials 4 are set.

FIG. 5 is a longitudinal sectional view of the entire mold when three glass materials are put in order to explain a case where a molded body is manufactured by a stopper, and FIG. 6 shows a plan view and a longitudinal sectional view of the stopper 6.

Next, a specific molding method of the molded body will be described with reference to FIG. In the state of FIG. 5, the molding material 7 (width u in the figure) is heated by heating the glass material under the molding conditions shown in FIG. 8, and the molding material 7 is pressurized to zero from the top.

FIG. 7 is a longitudinal sectional view showing a state of the mold at the time of completion of molding in which the upper mold 3 is moved by pressurization up to the thickness of the stopper 6 (width t in the figure).

As a result of molding glass containing 20 wt% SiO2, 30 wt% B2 O3, 10 wt% Li2O, 10 wt% TiO2 and 30 wt% other components at 550 ° C. and a molding pressure of 40 kgf, the diameter is 1.25 mm. A 6 mm shaped body was obtained. The processing accuracy of this molded body was ± 1 μm or less due to the stopper structure, and an extremely high precision molded body was obtained, which was uniformly ± 1 μm or less even in the outer circumferential direction.

It is a perspective view which shows the general shape of the molded object which can be acquired by this shaping | molding. It is a perspective view which shows the completion state of the molded object shape | molded by this invention. It is a longitudinal cross-sectional view of the whole metal mold | die used for shaping | molding in the Example of this invention. It is a longitudinal cross-sectional view of the shaping | molding part (cavity) in a metal mold | die. It is a tree sectional view of the whole metal mold | die at the time of putting three glass materials for demonstrating the case where a molded object is manufactured with a stopper. It is the top view and longitudinal cross-sectional view of the stopper 6. FIG. It is a longitudinal cross-sectional view which shows the state of the metal mold | die at the time of the completion of shaping | molding which the upper mold | type 3 moved by pressurization to the thickness of the stopper 6 (width t in a figure). It is a graph which shows the relationship of the temperature pressure / time at the time of manufacture of the molded object of implementation of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Body type | mold 2 ... Upper type | mold 3 ... Lower type | mold 4 ... Glass material 5 ... Cavity 6 ... Stopper 7 ... Adjustment part

Claims (3)

Two or more glass materials are arranged on the molding surface of the lower mold using a mold composed of at least a lower mold and an upper mold, and the glass material and at least the lower mold are brought to a temperature at which the glass material can be press-molded. In the method of manufacturing a glass molded body having a predetermined shape by deforming and integrating the glass by press-molding the heated glass material with the mold, the volume of the voids in the non-fused portion is increased. A method for producing a glass molded body characterized by obtaining a glass molded body having a highly accurate shape by adjusting. 2. The method for producing a glass molded body according to claim 1, wherein the total volume of the glass material is made smaller than the volume of the cavity of the mold after the mold is pressed as means for adjusting the gap of the non-fused portion. . 2. The apparatus according to claim 1, wherein a stopper is provided on at least one of the upper mold and the lower mold as means for adjusting the gap of the non-fused portion in claim 1, and the upper and lower molds are fixed at predetermined positions during pressing. A method for producing a glass molded body.

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