JPS62292629A - Molding device for glass lens - Google Patents

Abstract

PURPOSE:To efficiently mold a high-precision lens by separating two preheating stages for heating a glass stock and a molding tool, a pressurizing stage wherein the glass stock is deformed by heating and pressurization and cooled while being pressurized and a stage for performing only cooling and making these stages independent. CONSTITUTION:Two preheating stages 3, 4 for heating all parts of a molding block wherein a couple of molding tools and barrel molds separated from a molding device and a glass stock are integrated into one body, a pressurizing stage 5 capable of heating of the preheated molding block via the molding molds, pressurization deformation and pressurization cooling and a cooling stage 6 wherein the pressurized and cooled all parts of molding block are cooled near to the room temp. are arranged in the same chamber 1.

Description

DETAILED DESCRIPTION OF THE INVENTION 3. Detailed Description of the Invention Field of Industrial Application The present invention relates to a glass lens molding apparatus for forming glass lenses used in optical equipment by a precision glass molding 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, making it unsuitable for precise lens molding. Therefore, a common method is to pre-press a glass material into a certain shape, feed it between molds, heat it, and press-mold it. (For example, JP-A-58-84134, JP-A-60-200833, etc.).

The conventional molding method mentioned above will be explained below with reference to the drawings. FIG. 4 is a sectional view showing a state in which a lens is formed by molding a disk-shaped glass material by one of the conventional methods. 44 is a molded lens, 41 and 42 are a pair of molds, and 43 is a barrel mold. 45 is a heater 46, and 47 is a part of a molding device having a pressurizing mechanism. The glass material is supplied into the mold, and the mold and the glass material are heated to a temperature near the softening point of the glass by the heater 45.
Pressure molding is performed using a mold. After the deformation is completed, the mold and the molded lens are gradually cooled, and when the temperature reaches a temperature at which the lens 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, the temperature at which glass used for optical purposes can be formed is a high temperature of 500 to 700°C, so the heating, pressure forming, and cooling of the mold and glass material must be constant. It takes a long time from the time the glass material is introduced until the lens is molded. As a result, there is a problem that the efficiency of the molding apparatus is not improved and the cost required for molding is high. Furthermore, if the glass is deformed to shorten the molding cycle and the mold is opened before it has cooled sufficiently, or if it is cooled without applying pressure, there is a problem that the precision required for the lens cannot be achieved. In addition, the cost of the lens is greatly affected by the cost and life of the mold, and the number of mold surfaces used is large for the same production volume (as is true, the final lens also has the problem of being expensive).

SUMMARY OF THE INVENTION In view of the above-mentioned problems, an object of the present invention is to provide a glass lens molding apparatus capable of press-molding lenses with high shape accuracy, high area coverage, and low cost.

Means for Solving the Problems In order to solve the above problems, the glass lens molding apparatus of the present invention separates the mold from the molding apparatus and integrates the pair of molds, the circular mold, and the glass material into a molding block. The molding device uses two preheating stages, a pressure stage, and a cooling stage, and the glass material and mold are integrated, and the formed molded block is processed using the first and second preheating stages. After heating to a deformable temperature,
It is transferred to a pressure stage and deformed under pressure. After the deformation is completed, the stage is cooled down to a predetermined temperature while being pressurized with the same stage, and then the pressure is released and the stage is transferred to a cooling stage and molded. Allow the entire block to cool to near room temperature.

At this time, the temperatures of the second preheating stage and the pressure stage are maintained at or above the yield point of the glass to facilitate glass deformation, and after the glass deformation, only the temperature of the pressure stage is maintained at the transition point of the glass. Cool down to below, and continue pressurizing. After that, the pressure is released and the molded block is transferred to the cooling stage.At the same time, the temperature of the pressure stage is raised to a temperature higher than the initial glass yield point, and the same process is repeated while waiting for the next molded block to be transferred. It uses the means of carrying out the process.

The present invention uses the above-described means to separate and independently separate two preheating stages that heat the glass material and the mold, a pressurizing stage that deforms the glass material by heating and pressurizing it, and cooling it while applying pressure, and a stage that only performs cooling. By doing so, it becomes possible to keep the temperatures of the two preheating stages and the cooling stage constant, the molding cycle of the pressurizing stage can be shortened to the maximum, and the efficiency of the molding apparatus can be increased. Furthermore, by arranging the stages described above in the same chamber, the cost of the apparatus can be reduced. In addition, since glass deformation is possible at temperatures above the glass transition point, if pressure is stopped during cooling, the shape accuracy of the molded lens may shift due to residual strain caused by molding. Apply pressure to the transition point of the glass.
a. Since glass cannot be deformed below its transition point, the pressure is released and the glass is transferred to a cooling stage to be cooled.

This makes it possible to efficiently mold lenses with high precision.

EXAMPLE Hereinafter, an example of the glass lens molding apparatus of the present invention will be described in detail with reference to the drawings.

First, to explain the configuration shown in FIG. horizontal direction) - arranged in columns. Above the first and second preheating stages 3.4 and pressurizing stage 5, first and second preheating blocks 7.8 and pressurizing block 9 are arranged as opposed to each of the above stages. The distance between each stage and each block facing each other is set to be a predetermined amount larger than the height to the molding block constituted by the upper die 10, the lower die 11, the circular die 12, and the glass material 13.

The pressurizing block 9 is equipped so as to be freely vertically movable by a required stroke via a press cylinder 14 (in the Z direction in the figure).

A heater 15 is embedded in the first and second preheating stages 3.4, the pressure stage 5, the first and second preheating blocks 7.8 and the pressure block 9, which can raise the temperature to a desired degree. . The cooling stage 6 has a cooling water inlet 16 and an outlet 17 connected to an external temperature controller (not shown) in order to efficiently cool the entire molded block.

Further, a thermocouple (not shown) is embedded in each stage and each block to detect a predetermined temperature.

To control the atmosphere inside the chamber 1, an inlet 18 and an outlet 19 for inert gas or the like are connected.

Further, each stage is installed on the same surface so that the molded block can be transferred, and the first preheating stage 3 and the outside of the chamber are connected by a preparation table 20. Further, the cooling stage 6 and the outside of the chamber are connected by a support 21.

An inlet 22 for the forming block A is provided on the right side of the chamber 1, and a shutter 23 that can be opened and closed is provided. On the other hand, an exit 24 is provided on the left side, and the shutter 2
5 are arranged.

The molded block A is transferred onto the first preheating stage 3 in the chamber 1 by the cylinder 27 pushing the push rod 26 a predetermined amount in the exX direction in the figure.

On the other hand, as a means of transport between stages, as shown in Figure 2,
The holders 29, 30, 31, and 32 provided on the transfer rod 28 arranged in the chamber 1 are fixed at the same pitch P as the arrangement pitch between the stages, and move left and right on the transfer rail 33 in the X direction. It moves freely by a predetermined i1P. Further, the transfer rail 33 and the rod 28 as a whole can be moved by a predetermined amount in the Y direction (freely forward and backward) on another transfer rail 34.

Next, a means for molding a lens using the above-mentioned molding apparatus is shown in FIG. 1 and FIG. , placed on the preparation table 20.

In the molding device, the shutter 23 at the entrance 22 is first opened, and the molding block A is ejected by the push rod 26 and cylinder 27.
It slides on the preparation table 20 in the direction X (to the left) and is transferred onto the first preheating stage 3. When the transfer is complete, push rod 2
6 is returned to its original position by the cylinder 27, and the shutter 23 is closed. When the shutter 23 is open, the intake port 1
Since the internal pressure inside the chamber 1 is high due to the gas pressure from the chamber 8, the atmosphere does not have a negative effect on lens molding. The molding block A is heated to a predetermined temperature, which is preheated by the heater 15 in the first preheating stage 3 and the first preheating block 7 . The first predetermined temperature mentioned here does not necessarily have to be a temperature at which glass molding is possible, but rather is a temperature setting aimed at preventing thermal cracks due to rapid heating of the mold and improving the life of the mold.

The heated molded block A is transferred to the transfer rod 2 shown in FIG.
8 first moves in the -Y direction (toward the front side), and with the forming block A held at the tip of the holder 29 (shape B in the drawing), -X
Immediately after moving a predetermined amount P in the direction (left side) and transferring it onto the second preheating stage 4, the holder 28 moves in the +Y direction (backward), and the holder 29 leaves the forming block A and moves back in the X direction. The transfer is completed by moving a predetermined amount P to the right side). The second preheating stage 4 and block 8 are set at a predetermined temperature at which the glass can be deformed.

Note that when transferring from the first preheating stage 3 to the second preheating stage, the next molded block is transferred from the first preheating stage 3.
The transfer is postponed, and when the molded block A is transferred from the second preheating stage 4 to the pressurizing stage 5, the next molded block is sent from the preparation table 20 to the first preheating stage. That is, within the chamber, the arrangement of the molded blocks indicated by solid lines and the arrangement indicated by broken lines can be automatically performed alternately.

Next, the molded block A is transferred onto the pressurizing stage 5 by means of the transfer rod 28 and the holder 30 described above.

The temperature settings of the pressure stage 5 and the pressure block 9 are set to such a temperature that the glass material 13 can be deformed.
Pressure is applied in the -Z direction to deform the glass material 3. After the deformation is completed, that is, with the upper mold 10 in contact with the body mold 12, the pressure stage 5 and the heater 15 of the pressure block are turned off, and while the pressurized state is continued, that is, pressurized cooling is performed to a predetermined temperature. Cooling. During the deformation and pressure cooling mentioned above, the next molded block is on the first preheating stage 3.

After being pressurized and cooled to a predetermined temperature, the pressurizing block 9 is raised in the +Z direction by the cylinder 14, and is transferred onto the next cooling stage 6 using the rod 28 and the holder 31 by the aforementioned means. At this time, the next molded block that was on the first preheating stage 3 at the same time is transferred to the second preheating stage. That is, the molded blocks are arranged as indicated by broken lines in FIG. The molded block A transferred onto the cooling stage 6 is cooled to near room temperature by cooling water connected to the cooling water intake port 16 and the cooling water exit port 17.

Since the temperature of the pressurizing stage 5 and pressurizing block 9 is decreasing due to pressure cooling, the time that the molding block A is on the cooling stage 6 is the waiting time for the temperature to rise to a predetermined temperature, that is, the temperature at which the glass can be deformed. ing.

Furthermore, the cooling water is connected to an external temperature controller to cool the molded lens at a constant rate.

Next, the molded block A is transferred to the aforementioned transport means, namely the rod 2.
8 and the holder 32, the receiver slides on the stand 21 and is taken out of the chamber 1. At this time, the shutter 25 provided at the exit 24 in FIG. 1 opens in synchronization with the movement of the pole 28. The shutter 25 is closed at the same time as the pole 28 returns to the hatched position. The molded lens is taken out from the molding block A taken out from the chamber 1. Thereafter, by repeating the same operation, glass pressing with high shape accuracy can be performed continuously. In this embodiment, the forming blocks were fed intermittently, but continuous feeding is also possible if the timing of each stage is adjusted.

Effects of the Invention The reason why two preheating stages are provided in the present invention is that the pressure stage satisfies the two functions of pressure deformation and pressure cooling, so that the temperature drop that occurs can be avoided without placing the molded block on it. By increasing the temperature of the pressurizing stage with thermal efficiency, it is possible to shorten the molding time.

Furthermore, instead of raising the preheating of the molding block all at once to the glass deformation temperature, it can be raised gradually in two stages, which extends the life of the mold and contributes to reducing the cost of molded lenses, making it an industrially viable option. This is a glass lens molding device with high utility value.

[Brief explanation of the drawing]

Fig. 1 is a front view showing an embodiment of the glass lens molding apparatus of the present invention, Fig. 2 is a plan view illustrating the transfer means in the same embodiment, and Fig. 3 is a cross section of main parts illustrating a conventional example. It is a diagram.

Claims (1)

[Claims] A pair of molds separated from the molding device, a body mold, and two or more preheating stages that heat the entire molding block integrally made of the glass material, and through the mold of the preheated molding block, A pressurizing stage capable of heating, pressurizing deformation, and pressurizing cooling, and a cooling stage that cools the entire pressurized and cooled molded block to around room temperature are arranged in the same chamber. A glass lens molding device characterized by: