JPS63222022A - Molding method of glass lens - Google Patents

Abstract

PURPOSE:To efficiently obtain a precise glass lens suitable for optical instrument having high precision in one shot molding without a polishing process, by heating and molding a glass raw material in a mold under pressure, closely bringing a cooling block into contact with the mold, etc. and mechanically and enforcedly subjecting the molding to rapid cooling. CONSTITUTION:A tubular glass raw material 4 previously prefabricated is retained through a cylindrical mold 3 by molds 1 and 2 and press-molded with molding stage 5a and 5b heated with heaters 6a and 6b. As soon as the press molding is complete, the resultant molding is mechanically, enforcedly and uniformly subjected to rapid cooling by pressing hollow tubular cooling blocks 7a and 7b circulating cooling water inside and hollow tubular cooling block divided into 2 parts 8a and 8b to molding stages 5a and 5b and cylindrical mold 3 respectively and controlling cooling rate to about 180 deg.C/min.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method of forming a glass lens used in optical equipment by a precision glass forming method.

2. Description of the Related Art In recent years, many attempts have been made to form optical lenses by one-shot molding without a polishing process. The most efficient method is to pour the glass material from a molten state into a mold and press-form it, but it is difficult to control the shrinkage of the glass during cooling, so it is not suitable for precision lens molding. Therefore, it is generally appropriate to pre-process a glass material into a certain shape, supply it between molds, heat it, and press-form it. (For example, JP-A No. 5
8-84134, JP-A-60-200833, etc.).

The above-described molding method will be described below with reference to the drawings.

FIG. 2 is a sectional view showing a state in which a lens is formed by molding a disk-shaped glass material using one of the conventional methods. 14
is a molded lens, 11 and 12 are a pair of molds, 13
is torso-shaped. 15a and 15b are parts of a molding device having a pressurizing mechanism, and 16a and 16b are heaters.

The glass material held by the pair of molds IL 12 is heated through the body mold 13 by a heater 15a- to near the softening point of the glass.
The molding stage 15a-b is heated and pressure-molded through the molding stages 15a-b. After the deformation is completed, the mold and the molded glass 14 are slowly cooled, the press is opened at a constant temperature, the glass is cooled to a temperature at which the glass can be taken out, the mold is opened, and the lens is taken out.

Problems to be Solved by the Invention However, in the above method, since the temperature at which optically used glass can be formed is a high temperature of 500 to 700°C, the heating, pressure forming, and cooling of the mold and glass body are constant. It takes a long time from the time the glass body is introduced until the lens molding is completed. As a result, there is a problem that the efficiency of the molding apparatus is not improved and the cost of molding is high. Furthermore, if the mold is opened before sufficient cooling is performed to shorten the molding cycle, or if the mold is cooled without applying pressure, there is a problem in that the required precision as a lens cannot be obtained.

In view of the above problems, the present invention improves the efficiency of a molding device, and
The present invention provides a lens molding method with short molding tact and high precision.

Means for Solving the Problems In order to solve the above problems, the glass lens molding method of the present invention involves heating and pressing a glass material after supplying it into a certain mold, and controlling the cooling rate of the glass material after pressing. This is a molding method characterized by mechanically forcibly pressing a cooling block from the outside against the molding stage and barrel mold, which are heated and pressurized to accelerate the molding process.

Function The present invention is characterized in that, by the means described above, the tact time of the molding process that requires cooling while heating and pressurizing is shortened while maintaining the high precision required for the lens.

EXAMPLE An example of the glass lens molding method of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing the structure of a glass lens molding apparatus in an embodiment of the present invention. A pre-processed cylindrical glass material is held by a mold 1.2 via a body mold 3, heated by heaters 6a and 6b, and press-molded. In order to maintain the shape accuracy necessary for the lens, it is necessary to control the cooling rate near the glass transition point, and 6
Since the limit is 0°C/min and the glass transition temperature exists near the temperature at which the press can be opened, the pressurized cooling time exceeded 3 minutes. In the present invention, hollow cylindrical cooling blocks 7a-b are installed on the molding stages 5a-b, and hollow cylindrical cooling blocks 8a and 8b divided into two are installed on the body mold 3, and are pressed against each other at the same time as press molding is completed. Although not shown in the diagram, cooling water is circulating inside the cooling block, increasing the cooling rate by 1.
The temperature is controlled at about 80°C/min. In this method, the above structure cools the upper and lower surfaces and side surfaces of the mold simultaneously, making the cooling rate of the mold 1.2 and the body mold 3 uniform, so that the molded glass 4 can achieve the required lens performance. It is to be maintained. By the above-described molding method, molding can be performed in one minute of pressurized cooling time, and a lens with high precision can be supplied.

Effects of the Invention As described above, the present invention is capable of uniformly and mechanically cooling the glass body after it has been deformed by heating and pressure molding using a cooling process. The effect is that the molding takt time can be significantly shortened while maintaining high precision.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the molded state of a lens according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view showing the molded state of a glass lens according to a conventional method. L 2. IL 12...Mold, 3,13
...Body mold, 4.14...Molded glass, 5a/b, 15a/b...Molding stage, 6a-b, 15a-b...・Heater, 7a-
b, 3a-b... Cooling block. Name of agent Patent attorney Toshio Nakao 1 fool 7.2 - Molding mold 3 - Torso Ya L - Molding zabiota crow Sa, b - 1 molding Styshi Flo, b, 8o, b -- Reiu lock Figure 1 Convex 7 Otsu a 5゜68b b "77!1 b 11.12-11㎖ Shape Mold 13-Body Pear 74-1 Molded glass 15a, b-1 Molding stage 11, a, b--Heater Figure 2

Claims (1)

[Claims] A glass forming method in which a glass material is placed in a mold consisting of a pair of upper and lower molds and a body mold, and is heated and then press-formed, and after the press-forming, a cooling block is placed around the mold and the pressurizing part. A method for forming glass lenses characterized by forced cooling by bringing them into close contact with each other.