JPH06219753A - Forming apparatus of optical element - Google Patents

Abstract

PURPOSE:To continuously carry out press forming of an optical element using a pair of forming molds. CONSTITUTION:The forming apparatus consists of a hermetically sealable forming chamber 21 and a pair of forming molds (upper mold 22 and lower mold 23) installed in the interior thereof. A gas flow inlet 24 and a carrying-in and-out opening 26 for charging and discharging a glass raw material are installed in the forming chamber 21. The gas flow inlet 24 allows to carry a non-oxidizing gas into the forming chamber 21 and the carrying in and out opening 26 enables opening and closing by a shutter 27. The glass raw material 25 used in forming is carried on a carrying dish 28 and carried in and out from the carrying in and out opening 26 by an arm 29 for carrying.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical element for molding an optical element such as a lens by sandwiching a glass material heated and softened between a pair of molding dies having a mirror-finished surface and pressing the glass material. Molding apparatus.

[0002]

2. Description of the Related Art Generally, when molding is performed in the above-mentioned optical element molding apparatus, the molding die must also be heated to a high temperature (about 500 to 700 ° C.) near the glass softening temperature. In order to prevent oxidization and deterioration of the mold, keep the mold at high temperature in a non-oxidizing gas atmosphere such as nitrogen gas during pressing, and even if the mold is exposed to air when taking out the pressed optical element. Temperature without oxidation (about 300
The method of cooling to (℃) is adopted.

A conventional molding apparatus is disclosed in Japanese Patent Laid-Open No. 61-26.
The device described in Japanese Patent No. 528 is shown in FIG. This molding apparatus includes an intake chamber 1, a heating chamber 2, a molding chamber 3, and a cooling chamber 4.
And the take-out chamber 5 are made up of five chambers, each of which can be closed by shutters 6, 7, 8, 9, 10, 11 so that the interior can be filled with a non-oxidizing gas such as nitrogen gas. Has become.

In order to mold an optical element using this apparatus, a glass material 12 is placed on a support 14 together with a molding die 13, and an intake chamber 1, a heating chamber 2, a molding chamber 3, a cooling chamber 4 and a take-out chamber 5 are placed. Perform by passing through each of the five rooms in order.
In order to put the glass material 12 and the molding die 13 into the molding apparatus, after opening the shutter 6 and putting it in the intake chamber 1, the shutter 6 is closed and the air in the room is evacuated from the air discharge port 15, and instead. A non-oxidizing gas is filled from the gas inlet 16. On the other hand, from the molding device to the glass material 12
In the same manner, when the molding die 13 is taken out, the shutter 11 is closed, the air in the taking-out chamber 5 is evacuated from the air outlet 17, and the non-oxidizing gas is filled from the gas inlet 18 instead.

If molded in this way, the intake chamber 1
And the take-out chamber 5, the glass material 12 and the molding die 1
Since 3 is already in a cooled state, it can be freely taken in and out from the outside without being oxidized. In addition, when these two rooms come to and come from other rooms, because these rooms are made into a non-oxidizing atmosphere, air does not mix in the other rooms, and therefore, molding that is in a high temperature state in other rooms Type 1
There is no oxidation of 3.

[0006]

However, in the above-mentioned conventional molding apparatus, the molding die 1 together with the glass material 12 is used for the apparatus.
Since 3 is also charged, a plurality of sets of molding dies 13 are required to continuously mold the optical element. However, since this molding die 13 requires excellent durability and high shape accuracy, it is expensive and it is economically unfavorable to use a plurality of molding dies 13. On the other hand, a method of repeatedly using one set of molding dies 13 may be considered,
Each time the glass material 12 is taken in and out of the device, a molding die 13
In order to prevent the oxidation of the mold, heating and cooling of the molding die 13 are repeated, and there is a problem that molding is intermittent.

The present invention has been made in view of the above conventional problems, and provides an optical element molding apparatus capable of continuously press-molding an optical element using one set of molding dies. With the goal.

[0008]

In order to solve the above problems, the present invention is a molding apparatus for pressing a softened glass material with a pair of molding dies facing each other to obtain an optical element, wherein the molding dies are In a molding apparatus for an optical element, which is arranged in a hermetic molding chamber filled with a non-oxidizing gas, and in which the molding chamber has a loading / unloading port for loading / unloading a glass material, the outside of the molding chamber from the loading / unloading port. A means for producing a non-oxidizing gas flow was provided.

1 and 2 are conceptual views showing a molding apparatus for an optical element according to the present invention. This molding apparatus is composed of a hermetic molding chamber 21 and a set of molding dies (upper mold 22 and lower mold 23) installed therein, and the molding chamber 21 includes a gas inlet 24 and a glass material. Carrying in / out port 26 for loading / unloading 25
And are attached. A non-oxidizing gas can be introduced into the molding chamber 21 from the gas inlet 24, and the carry-in / out port 26 can be opened and closed by a shutter 27. The glass material 25 used for molding is the transport tray 2
It is configured to be placed on and taken out from the carrying in / out port 26 by the carrying arm 29.

[0010]

A method of molding an optical element by the molding apparatus of the present invention having such a structure will be described. First, a non-oxidizing gas such as nitrogen gas is flown into the molding chamber 21 through the gas inlet 24 to create a non-oxidizing atmosphere in the molding chamber 21 and the shutter 27 is closed to close the upper mold 22 and the lower mold 23. Keep the temperature near the glass softening temperature. This completes the preparation for molding. The optical element is molded by successively feeding the glass material 25 that has been heated and softened into the molding chamber 21 and pressing it between the upper mold 22 and the lower mold 23 (see FIG. 2).

At this time, the glass material 25 is put into and taken out of the molding chamber 21 in a non-oxidizing atmosphere, while the non-oxidizing gas is replenished into the molding chamber 21 through the gas inlet 24 while the carry-in / out port 26 is provided.
If the shutter 27 is opened, the non-oxidizing gas flows out from the carry-in / out port 26, so that the outside air does not enter the molding chamber 21 (see FIG. 1).
reference). Therefore, even when the glass material 25 is charged into the molding chamber 21 or the molded optical element is taken out of the molding chamber 21, the upper mold 22 and the lower mold 23 are kept in a non-oxidizing atmosphere, and thus the conventional mold is not used. Each type 2
It is not necessary to cool the lower mold 23 and the lower mold 23, and continuous molding of optical elements is possible with one mold.

[0012]

Embodiment 1 FIGS. 3 and 4 show a molding apparatus of this embodiment, which comprises a hermetic molding chamber 31 and
Upper mold 32 and shaft 33 installed above the inside
Lower mold 34 that is moved up and down by the following, a carry-in / out port 36 under the molding chamber 31, which is divided by a shutter 35, and gas nozzles 37a, 37b, 37c provided in various places of the apparatus.
It is composed of and. Glass material used for molding 2
The device 5 is configured to be placed on a carrying tray 38 and to be taken in and out from the carry-in / out port 36 by a carrying arm 39.

In the gas nozzle 37b, the direction of the jetted nitrogen gas and the direction in which the transfer arm 39 moves forward and backward are the same,
Moreover, it is provided so that the nitrogen gas is ejected almost at the center of the opening of the carry-in / out port 36. In addition, the two gas nozzles 37c, 37c allow the nitrogen gas to be ejected from the carry-in / out port 36.
Of the carrying-in / out port 36 in a state inclined with respect to the advancing / retreating direction of the transfer arm 39 so that a gas flow of nitrogen gas is generated in a direction in which the transfer arm 39 moves backward.
Are arranged to face the upper and lower wall surfaces of the.

The operation of the gas nozzles 37a, 37b, 37c will be described below. When the shutter 35 of the carry-in / out port 36 is closed, the gas nozzle 37
The gas flow of nitrogen gas from a and 37b has a function of increasing the pressure in the molding chamber 31, and the gas flow from the gas nozzle 37c has a function of supplying nitrogen gas into the carry-in / out port 36.

On the other hand, when the shutter 35 is open,
The gas flow from the gas nozzles 37a and 37b has a function of increasing the pressure in the molding chamber 31, and the gas flow of nitrogen gas from the gas nozzle 37b increases the pressure in the molding chamber 31 and is discharged from the gas nozzle 37b. It has a function of generating a gas flow in the direction of the inlet 36 and forcibly discharging the gas in the molding chamber 31 from the carry-in / out port 36. The nitrogen gas flow from the gas nozzle 37c has a function of assisting the gas flow from the gas nozzle 37b to discharge the gas in the molding chamber 31.

A method for molding an optical element by using the molding apparatus of this embodiment having the above-mentioned structure will be described. As a preliminary preparation for molding, first, the gas nozzle 37a,
Nitrogen gas is flown from 37b to leave the molding chamber 31 in a non-oxidizing atmosphere, and the shutter 35 is closed. At this time, when the shutter 35 is closed and the nitrogen gas is introduced after the air inside the molding chamber 31 is evacuated by auxiliary means such as vacuum exhaust in advance, a non-oxidizing atmosphere can be efficiently created. Further, since air may leak from the outside of the molding chamber 31 into the room, it is preferable to set the atmospheric pressure in the molding chamber 31 to be slightly higher than the atmospheric pressure. Next, the upper mold 32 and the lower mold 34 are heated to near the glass softening temperature by the heaters 32a and 34a, respectively. This completes the preparation for molding.

The molding is performed as follows. First, nitrogen gas is jetted from the gas nozzle 37c to sweep away air in the vicinity of the carry-in / out port 36, and the gas nozzles 37a and 37b
The shutter 35 is opened while further injecting nitrogen gas. At this time, an air flow of nitrogen gas flowing out from the carry-in / out port 36 is generated. Then, the glass material 25 that has been heated and softened in advance is placed on the transfer tray 38, and is placed by the transfer arm 39 from the carry-in / out port 36 onto the lower mold 34 in the molding chamber 31, and the transfer arm 39 is retracted. After that, the shutter 35 is closed and the supply of nitrogen gas from the gas nozzles 37a, 37b, 37c is stopped. Here, the nitrogen gas to be sprayed may be preheated so as not to cool the high temperature upper and lower molds 32 and 34 and the glass material 25. Glass material 2 by the above work
5 is carried into the molding chamber 31. Next, shaft 3
3 is driven to raise the lower mold 34 on which the glass material 25 is placed, and the glass material 25 is sandwiched between the upper mold 32 and the lower mold 34 for press molding.

Finally, in order to take out the glass material 25 thus molded into the optical element from the molding chamber 31, as in the case where the glass material 25 is loaded into the molding chamber 31,
Inlet / outlet port 36 by injecting nitrogen gas from the gas nozzle 37c
After the air in the vicinity of is cleaned (see FIG. 3), the shaft 33 is driven to lower the lower mold 34 and the glass material 25 to the carry-in / out port 36. Next, while the nitrogen gas is being ejected from each of the gas nozzles 37a, 37b, 37c, the shutter 35 is opened, and the glass material 25 formed into the optical element is taken out using the carrying arm 39 (see FIG. 4). After taking out the glass material 25, the shutter 35
Is closed and the supply of nitrogen gas from each of the gas nozzles 37a, 37b, 37c is stopped, and a series of optical element molding operations is completed.

As described above, according to this embodiment, when the glass material 25 is carried in and out of the molding chamber 31, the carry-in / out port 36 is used.
Since a nitrogen gas flow from the outside to the outside is generated, air does not enter the forming chamber 31, and the non-oxidizing atmosphere in the forming chamber 31 can be maintained. Therefore, the upper mold 32
Since the lower mold 34 can be maintained at a high temperature all the time without being deteriorated by oxidation, the optical elements can be continuously press-molded one after another.

If a means for ejecting nitrogen gas is provided in the molding chamber 31, the pressure in the molding chamber 31 will be higher than the pressure in a place other than the molding chamber 31, so the molding chamber 31 will be sealed. When the shutter 35 is opened, the nitrogen gas flows out from this opening, but according to the present embodiment, the gas nozzle 37b for ejecting the nitrogen gas toward the carry-in / out port 36 direction.
Is provided in the molding chamber 31, and a gas nozzle 37c for ejecting nitrogen gas so as to generate a gas flow of nitrogen gas in the backward direction of the transfer arm 39 is provided in the carry-in / out port 36. It is possible to force outflow of nitrogen gas from.

In this embodiment, nitrogen gas is used to create a non-oxidizing atmosphere in the molding chamber 31, but the present invention is not limited to this embodiment, and the upper die 32 and the lower die are used. Any gas that does not oxidize 34 may be used. For example, a weakly reducing gas in which 95% nitrogen and 5% hydrogen are mixed may be used. Further, although the carry-out port and the carry-in port of the glass material 25 are the same, they may be separate from each other.

[0022]

[Embodiment 2] FIGS. 5 and 6 show a molding apparatus according to the present embodiment. The same components as those in Embodiment 1 are designated by the same reference numerals as those in FIGS. 3 and 4, and the description thereof is omitted. . In the molding apparatus according to the first embodiment, the lower mold 34 performs both the work of transporting the glass material 25 from the carry-in / out port 36 to the upper mold 32 and the pressing work. The work is performed by an elevator 41 that is vertically movable in the molding chamber 31 and push rods 42 and 43 that are horizontally movable in the molding chamber 31.

The method of molding using the molding apparatus of this embodiment is as follows. First, as in the first embodiment, the interior of the molding chamber 31 is filled with nitrogen gas, and the gas nozzle 3
The carrier plate 38 and the glass material 25 are carried onto the elevator 41 by the carrier arm 39 while injecting nitrogen gas from 7a, 37b, 37c. Next, when the elevator 41 is lifted up to the push rod 43, the push rod 43 is pushed out and the glass material 25 and the transport tray 38 are placed on the sleeve 44 in which the lower mold 34 is inserted (see FIG. 5). The lower die 34 is raised by the shaft 33 slidably fitted in the sleeve 44, and the glass material 25 is pressed by the upper die 32 and the lower die 34.

In order to take out the glass material 25 molded into the optical element, the lower mold 34 is retracted into the sleeve 44, the push rod 42 is projected, and the glass material 25 and the transport tray 38 are returned to the top of the elevator 41. When 41 is lowered to the loading / unloading port 36, it is taken out in the same manner as when loading (see FIG. 6).

According to this embodiment, the optical element can be continuously molded as in the first embodiment, and the lower mold 34 is always used.
Is located away from the carry-in / out port 36, even if air may come in through the carry-in / out port 6, the lower mold 34
Has the advantage that it is difficult to oxidize.

[0026]

[Third Embodiment] FIG. 7 shows a molding apparatus according to the present embodiment. The same components as those of the first embodiment are designated by the same reference numerals as those in FIGS. 3 and 4, and the description thereof will be omitted.
In this embodiment, a gas outlet 45 is added to the carry-in / out port 36 of the apparatus of the first embodiment, and when the glass material 25 is taken in and out from the carry-in / out port 36, nitrogen gas is jetted from the gas nozzles 37a, 37b, 37c, and at the same time, the gas The vacuum suction is performed from the discharge port 45.

In this embodiment, in addition to having the same effect as that of the first embodiment, the air that is about to enter the molding chamber 31 through the carry-in / out port 36 is sucked out through the gas discharge port 45, and also from the gas nozzle 37c. Since it is pushed back by the injection of nitrogen gas, there is little possibility that air will enter the molding chamber 31, and there is an advantage that the upper mold 32 and the lower mold 34 are less likely to be oxidized.

[0028]

As described above, according to the optical element molding apparatus of the present invention, the molding die does not oxidize and deteriorate,
The optical element can be continuously molded by one set of molding dies.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing the concept of an optical element molding apparatus of the present invention.

FIG. 2 is a vertical cross-sectional view showing the concept of an optical element molding apparatus of the present invention.

FIG. 3 is a vertical cross-sectional view showing a molding apparatus of Example 1 of the present invention.

FIG. 4 is a vertical cross-sectional view showing a molding apparatus of Example 1 of the present invention.

FIG. 5 is a vertical cross-sectional view showing a molding apparatus of Example 2 of the present invention.

FIG. 6 is a vertical sectional view showing a molding apparatus of Example 2 of the present invention.

FIG. 7 is a vertical cross-sectional view showing a molding apparatus of Example 3 of the present invention.

FIG. 8 is a vertical sectional view showing a conventional molding apparatus.

[Explanation of symbols]

 3,21,31 Molding room 6,7,8,9,10,11,27,35 Shutter 12,25 Glass material 13 Mold 16,18,24 Gas inlet 22,32 Upper mold 23,34 Lower mold 26 , 36 Carry-in / out port 37a, 37b, 37c Gas nozzle

Claims (1)

[Claims] 1. A molding apparatus for obtaining an optical element by pressing a softened glass material with a pair of molding dies opposed to each other, wherein the molding dies are arranged in a hermetic molding chamber filled with a non-oxidizing gas. In the molding apparatus of the optical element, in which the molding chamber is provided with a carry-in / out port for loading and unloading the glass material, a means for generating a non-oxidizing gas flow from the carry-in / out port to the outside of the molding chamber is provided. Characteristic optical element molding equipment.