JP3216100B2 - Manufacturing method of precision glass products - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a precision glass product by directly molding a high-precision glass product such as an aspherical lens from a molten glass in a series of steps including press forming. is there.

[0002]

2. Description of the Related Art In recent years, as a method of manufacturing precision glass products such as optical elements, instead of a processing method of grinding and polishing a glass molded article formed into a predetermined shape, a glass material is reheated to soften and formed. Attention has been paid to a method of directly press-molding in a mold.

Usually, in a method of manufacturing a precision glass product by press molding of this type, a soft glass material is press-molded in a non-oxidizing atmosphere using a molding member composed of upper and lower dies. Then, a shape corresponding to the molding surface of the mold member is transferred to the glass material, and then the molded product is cooled in the molding die and then taken out of the molding die at a required temperature or lower.

[0004] The glass material used here may be a material whose surface has been smoothed in advance by grinding and polishing, heat treatment, chemical treatment, or the like, or a glass preform having a desired shape without surface defects from a molten glass. Obtained and used as it is for press molding, and various shapes such as a ball shape and a flat shape are used.

[0005]

However, in the conventional method of preforming a glass material, reheating and press-forming the glass material, the steps of preforming the glass material and the press-forming process are separated. However, if the molten glass flowing out of the outlet of the melting furnace is thermally deformed to obtain a glass lump of a required shape, and even if this is directly used as a glass material for the press forming process, the glass In addition to the labor and time required for cooling and transporting, a cleaning process for removing foreign matter causing surface defects and an inspection process thereof are required before the press molding process. Furthermore, considerable energy is required for reheating in the press forming step, and this loss is large, and the production efficiency is greatly reduced.

[0006] In order to solve the above problems, it is ideal to carry out integrated production from melting of glass to finished products. Japanese Patent Application Laid-Open No. 3-45523 discloses that a molten glass flowing out of an outlet of a melting furnace is received by a first thermal processing jig in a non-oxidizing atmosphere, and then a second thermal processing jig is provided. A method of manufacturing an optical element in which a tool is brought into contact with molten glass, and after being inverted in that state, a certain glass preform is formed on the heat processing jig by thermal deformation, and the glass preform is press-formed with a forming die. Has also been proposed.

However, even in this case, there are a number of problems to be solved as described below in order to realize the above-described ideal production. (1) There are the following problems in providing a glass melting furnace, particularly, providing the glass outlet in a non-oxidizing atmosphere. That is,
The glass material near the glass outlet is difficult to vitrify because the temperature of the outlet must be lowered to suppress the outflow of glass until the start of glass outflow. Since it cannot be performed, it contains a large amount of bubbles, striae, and the like, and it is impossible to cause good-quality glass to flow out of the glass outlet from the beginning of the flow. Therefore,
At the start of the outflow, a significant amount of the outflowing glass must be discarded. Doing this in a small atmosphere space
Whether performed automatically or with the assistance of humans, there are many difficulties.

In addition, it is necessary to seal the atmosphere space at the same time as the heat retaining treatment for keeping the glass outlet at a high temperature, which complicates the structure of the apparatus. Furthermore, since a large amount of volatile matter is generated from the molten glass flowing out of the glass outlet, the atmosphere space is easily contaminated,
In some cases, dirt due to volatiles may adhere to the glass material, and the product may not be maintained at the required high quality. (2) Receiving molten glass in a mold in an atmosphere has the following problems. That is, as described above, when a large amount of volatiles is present in the atmosphere, it adheres to the mold,
Although the mold may be contaminated, cleaning of the mold is difficult because the mold is in the atmosphere space. Also, since the mold receives the molten glass, its temperature rises, so it is severely damaged, and it is necessary to frequently replace it with a new mold, but since the mold is in the atmosphere space, Exchange is difficult.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and a first object of the present invention is to realize a method for realizing glass forming with a high production efficiency in a consistent process from melting. It is an object of the present invention to provide a method for manufacturing a precision glass product in consideration of avoiding contamination of a space and maintaining high quality of a product.

A second object of the present invention is to simplify a process including formation of a glass preform, improve productivity, and avoid thermal deterioration of a press mold. An object of the present invention is to provide a method for manufacturing a glass product.

[0011]

In order to achieve the above object, the present invention provides a method of manufacturing a precision glass product from a molten glass in a series of steps including a press forming process. A step of receiving a predetermined amount of molten glass flowing out of the glass outlet into a receiving mold; a step of introducing a predetermined amount of molten glass received on the receiving mold together with the receiving mold into the replacement chamber; And a step of forming glass into a required shape in a non-oxidizing gas atmosphere in a replacement chamber or a forming chamber communicating with the replacement chamber.

Further, according to the present invention, in a method for manufacturing a precision glass product from a molten glass in a series of steps including press forming, a predetermined amount of molten glass flowing out of a glass outlet of a melting furnace is provided. Separating and adjusting the viscosity to a temperature of 10 ⁴ to 10 ¹⁰ dPa · s, and supplying the glass to a mold adjusted to a temperature of 10 ¹¹ to 10 ¹⁴ dPa · s for the viscosity of the glass. When,
Press forming the glass with a forming die.

[0013]

As described above, the glass flowing out of the glass outlet provided in the atmosphere is received by the mold, introduced into the replacement chamber controlled by the non-oxidizing gas atmosphere, and communicated with the replacement chamber or the replacement chamber. In a non-oxidizing gas atmosphere in the molding chamber,
Since the glass is preformed or fully formed, volatiles from the molten glass flowing out of the glass outlet are replaced in the replacement chamber,
It is possible to avoid bringing into the molding chamber, and even if volatile matter is brought into the replacement chamber, the volatile matter can be discharged to the outside by scavenging by vacuuming, so there is no risk of fouling the atmosphere space, and The quality can be ensured, and the cleaning of the mold can be stopped to the minimum necessary number, so that the production efficiency can be improved. In particular, since the evacuation is performed in a state where the glass surface is hardened to some extent after receiving the glass in the receiving mold, the generation of bubbles from inside the glass can be avoided,
It is possible to avoid contamination of the receiving mold due to volatile matter and keep the replacement chamber and the molding chamber clean. Furthermore, the exchange of the receiving mold can be facilitated by utilizing the inevitable state in which the receiving mold is exposed to the atmosphere from the replacement chamber for taking in the glass material.

Further, by controlling the temperature of the glass or the mold in the above-mentioned temperature range of 10 ⁴ to 10 ¹⁰ dPa · s or 10 ¹¹ to 10 ¹⁴ dPa · s in terms of glass viscosity. By directly receiving a desired amount of glass lump (glass gob) from the molten glass into one of a receiving mold or a molding die and performing preforming or main molding, the mold is not thermally damaged, and a molded product is formed. Good molding can be achieved without causing defects such as wrinkles due to heat shrinkage.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be specifically described below with reference to FIGS. FIG. 1 schematically shows an example of a manufacturing apparatus for realizing the manufacturing method of the present invention. Here, reference numeral 20 denotes a melting furnace which is placed in the atmosphere and melts a glass material.
Is lowered to an outlet 22 via an outflow pipe provided at the bottom of the melting furnace 20. A heater (not shown) is arranged around the melting furnace 20 and the outflow pipe 21 so that the glass material can be melted and the temperature of the glass flowing out from the outflow port 22 can be adjusted. I have.

A replacement chamber 10 is disposed below the outlet 22. The replacement chamber 10 is communicated with a molding chamber 11 via a gate valve 18, and the molding chamber 11 is connected to a removal chamber 12 via a gate valve 19. Is communicated to. When the receiving mold 1 placed inside the replacement chamber 10 is led out, the replacing chamber 10 receives the receiving mold 1.
The outlet 22 is disposed right above the chamber, and is composed of a replacement chamber chamber 13 and a replacement chamber lid 14 that opens the chamber 13 to the atmosphere or hermetically closes the chamber 13.

The chamber 13 is provided with a carry-in cylinder 32 at the side thereof, and a drive cylinder 35 at the bottom thereof for raising and lowering the receiving mold 1.
Provided with cylinders 32 and 35 respectively
Has the cylinder shafts 33 and 36 inserted into the replacement chamber 10 via seal rubbers 62 and 63. The receiving die 1 is attached to the tip of the cylinder shaft 36. In addition, receiving mold 1
Is constantly adjusted by the heater 51 to a predetermined temperature, for example, a temperature at which the glass viscosity becomes 10 ⁸ to 10 ¹² dPa · s.

Then, as shown in the figure, the molten glass flowing out of the outlet 22 is received by the mold 1, and a glass block 24 is formed on the mold 1 by thermal deformation of the glass. In this state, by driving the cylinder 35 and lowering the cylinder shaft 36, the receiving mold 1 is drawn into the replacement chamber 10 together with the glass block 24 formed thereon. In this state, the replacement chamber lid 14 is rotated in the direction of arrow A, closed via the seal rubber 61, and the replacement chamber 10 is closed.
, Is evacuated by an appropriate suction means (not shown), and then a non-oxidizing gas is supplied to make the inside of the replacement chamber 10 a gas atmosphere.

Before being drawn into the replacement chamber 10,
The glass block 24 on the receiving mold 1 releases most of the volatiles contained in the glass to the atmosphere. However, even after the glass block 24 is drawn into the replacement chamber 10, the replacement chamber 10 is scavenged by evacuation. Is released to the outside.

When the glass block 24 is preformed into a desired glass material shape only by thermal deformation (self-weight deformation), the gas in the replacement chamber is heated under the temperature conditions shown in the graph of FIG. At the stage when the replacement is completed, the gate valve 18 is opened, and the glass block 24 taken into the replacement chamber 10 is suctioned by the suction finger 34 attached to the tip of the cylinder shaft 33, and the cylinder 32 is driven to drive the glass block. 24 is sent from the replacement chamber 10 to the molding chamber 11.

However, the glass block 24 is mechanically preformed by the following means when it is not preformed into a desired glass material shape only by thermal deformation (self-weight deformation). That is, in this embodiment, a preformed cylinder 30 is attached to the outside of the replacement chamber lid 14, and the cylinder shaft 31 is inserted into the replacement chamber 10 via the seal rubber 69,
At the tip of the shaft 31, the upper die 2 for preforming, which includes a heater 52, is attached.

For this reason, at the stage where the replacement chamber lid 14 is closed and the evacuation and the gas replacement are completed, or before or during the process, the upper die under the temperature condition shown in the graph of FIG. Pre-press molding is performed in Step 2. Thereafter, as described above, the gate valve 18 is opened, the prepress-formed glass block 24 is suctioned by the suction finger 34 attached to the tip of the cylinder shaft 33, and the cylinder 32 is driven to remove the glass block 24. The material is sent from the replacement chamber 10 to the molding chamber 11.

In the drawing, reference numeral 53 denotes a heater 53 for controlling the temperature in the replacement chamber 10 so that a required gas atmosphere temperature can be secured.

The molding chamber 11 is provided with a molding die for the main molding in a molding chamber 15 which is formed airtight, and maintains airtightness with the outside. The molding chamber 15 is provided with an upper cylinder 37 and a lower cylinder 39 for precision molding, which are located on the upper and lower outer sides, respectively. Each cylinder 37, 39 has a cylinder shaft 38, 40, respectively. It is inserted into the molding chamber 11 via seal rubbers 64 and 65, and a hook 7 for opening and closing the upper mold 3 is attached to a lower portion of the shaft 38. A body mold 5 is placed between the shafts 38 and 40, and an upper mold 3 and a lower mold 4 are slidably inserted into a through hole vertically penetrating the body mold 5.

The upper mold 3 can be pressurized by the driving of the cylinder 37 via the tip of the shaft 38 at the time of pressurization for press molding.
The flange provided on the upper part of the upper die 3 can be pulled up by the hook 7 described above. The lower die 4 is supported by a bottom plate 6 attached to a lower part of the trunk die 5, and has a structure in which the lower die 4 can be moved up and down in a range of an internal space of the die 5. Further, the body mold 5 is provided with an upper mold heater 54 and a lower mold heater 55 for temperature adjustment of the upper mold 3 and the lower mold 4.

Thus, the glass lump introduced from the replacement chamber 10 by the suction finger 34 is placed on the lower die 4 and subjected to press forming adjusted to required temperature and pressure by lowering the upper die. At this time, the temperature of the molding die and glass molded product,
The control of the pressure is performed, for example, in the control mode of FIG. 6 or FIG. In this case, the molding chamber 11 has the same non-oxidizing gas atmosphere in the molding chamber 15.

The take-out chamber 12 is composed of a take-out chamber 16 and a take-out chamber lid 17, as in the case of the replacement chamber 10. The take-up chamber 16 is located at the bottom and sides of the take-up chamber. A cylinder 41 and a take-out cylinder 44 are provided. Both cylinders 4
1, 44 inserts one end of each of the cylinder shafts 42, 45 into the removal chamber 12 via seal rubbers 67, 68, respectively. A stand 43 for receiving a glass molded product is attached. A suction finger 46 is attached to the tip of the shaft 45, and the cylinder 44 is driven to
When moving back and forth, the molded product on the lower mold 4 is sucked, and the molded product can be placed on the table 43.

The lid 17 and the take-out chamber 16
A seal rubber 66 is attached between the opening 17 and the opening so that when the lid 17 is closed, airtightness can be maintained. Further, in the above-described mold chamber 15 and removal chamber 16, similarly to the replacement chamber 13, means (not shown) for evacuation including an exhaust port,
A supply means (not shown) for supplying the atmospheric gas is provided.

(Example 1) Hereinafter, the production method of the present invention will be described with reference to specific and numerical embodiments. here,
Using the apparatus described above, the effective diameter of the shape shown in FIG.
The process for forming a precision glass product (concave meniscus lens) having a diameter of 3 mm and a product outer diameter of about 17 mm will be described. In the press molding, the viscosity was 1 at a temperature of 1040 ° C.
0 ^8.2 Pa · s at 580 ° C, 515 ° C
10 ¹¹ Pa · s at ℃, 10 ¹⁴ Pa · s at 465 ° C
A glass material having a viscosity characteristic of s was used.

First, the above-mentioned glass raw material is put into a melting furnace 20 to be vitrified, then defoamed and stirred to produce a homogeneous molten glass 23 and guided to an outflow pipe 21. In this case, the outflow pipe 21 is controlled to a temperature corresponding to 10 Pa · s in glass viscosity.

On the other hand, the gate valves 18 and 19 are closed and placed, the inside of the molding chamber 11 and the take-out chamber 12 is once evacuated, and then N ₂ gas is introduced as a non-oxidizing gas. Perform the replacement. In addition, the heaters 54 and 55 on the upper and lower parts of the body mold are energized to heat the upper mold 3 and the lower mold 4 to a temperature corresponding to a glass viscosity of 10 ^8.5 Pa · s.

The receiving mold 1 / if necessary, the upper mold 2 for preforming is heated to a temperature corresponding to a glass viscosity of 10 ¹² Pa · s using its heater 51/52.

Then, the replacement lid 14 was opened, the cylinder 35 was driven, and the receiving mold 1 was moved directly below the outlet 22. As shown in FIG. 4 (1), the glass was discharged from the outlet 22 and received by the receiving mold 1, and a predetermined amount of molten glass lump was formed on the receiving mold 1 by its own weight deformation. Next, the drive shaft 36 was lowered, and the replacement chamber lid 14 was closed. Immediately thereafter, the cylinder 30 for preforming was operated, and the glass block on the receiving mold 1 was pressed by the upper mold 2 at a pressure of 500N.
Then, the glass material 24a having a desired shape was obtained by preliminary molding (see FIG. 4 (2)).

After the preforming, the surface of the glass becomes 10 ⁶ Pa ·
When the viscosity reached s or more, the inside of the replacement chamber 10 was evacuated for 10 seconds, and then a non-oxidizing gas (N ₂ gas) was introduced into the replacement chamber 10 for 5 seconds. Thereafter, the gate valve 18 is opened, the carry-in cylinder 32 is driven, the shaft 33 is advanced, the suction finger 34 is moved onto the preformed glass material 24a, and then the shaft 36 is raised and the glass 36 is raised. The material 24a was sucked by the suction finger 34, and then the shaft 36 was released downward. Then, the cylinder 32 is further driven, and the shaft 3
In the operation of 3, the glass material 24a was guided to the molding chamber 11, and was placed on the lower molding die 4 (the viscosity of the glass at this time was 10 ⁹ P
a.s, and the upper and lower dies 3, 4 at this time are each set to a temperature corresponding to 10 ^8.5 Pa.s in terms of glass viscosity.) Then, return the shaft 33 to the gate valve 1
8 was closed.

In the molding chamber 11, the cylinder 37
And lowers the upper die shaft 38 until the lower surface of the flange of the upper die 3 completely abuts against the upper surface of the trunk die 5.
A pressure (5000 N) was applied to the upper mold 3 for 60 seconds to form a required precision glass product.

After that, the lower surface of the flange of the upper mold 3 is
The glass molded product is cooled in the molding die while keeping the above state of abutting against the upper surface of the lower mold cylinder 39 so that the lower die 4 follows the glass molded product 24b as it shrinks. Was operated, and the lower mold 4 was pressed at the tip of the lower mold shaft 40 from the bottom with a pressure of 3000N.

The glass has a viscosity of 10 ¹⁴ Pa
When the temperature reaches s, the pressurizing operation by the lower cylinder 39 is stopped, and then the upper cylinder 3
The upper mold 7 was moved upward, the flange of the upper mold 3 was hooked by the hook 7 fixed to the upper mold shaft 38, and the upper mold was raised to open the mold.

Next, the gate valve 19 is opened, the take-out cylinder 44 is driven, and the suction finger 46 provided at the tip of the take-out shaft 45 is moved to above the lower mold 4 to suck the obtained glass molded product 24b. . Thereafter, the take-out cylinder 44 is returned, stopped on the table 43, and the table drive cylinder 41 is moved to move the table 43 to the glass 24b.
When the finger 46 was moved to a position where it touched the lower surface, the suction of the finger 46 was released. In a state where the mounting table 43 supports the glass molded product 24b, the cylinder 41 is driven to move the shaft 42 downward, and as shown in FIG. 45 was returned to the retracted position. In this state, the gate valve 19 was closed, the take-out chamber lid 17 was opened, and the molded product 24b was taken out of the take-out chamber 12 by appropriate hand means. Then, the lid 17
Was closed, and the inside of the extraction chamber 12 was replaced with a non-oxidizing gas atmosphere by the above-mentioned operation to prepare for the next extraction.

Actually, this molding operation was repeated 100 times continuously and the quality of the obtained precision glass product was confirmed. No abnormality was found in the appearance of the product, and the surface precision was not improved. Both ass and habits were good within one. At this time, the surface of each of the dies 1, 2, 3, and 4 was observed, but no harmful volatiles were found to be adhered, and it was still in a state where continuous molding could be sufficiently performed.

Comparative Example 1 In order to compare the embodiment according to the present invention with the embodiment according to the prior art,
In the apparatus and operation of Example 1 above, except for vacuum degassing and N
_{(2) When} only preforming was continuously performed without introducing gas, deposits were deposited on the molds 1 and 2 after about 30 shots, and a glass product having a good appearance was obtained. lost.

When the replacement operation was immediately performed in the replacement chamber 10 with the glass viscosity being 10 ³ Pa · s, many bubbles generated from inside the glass were observed in the glass material 24a. Could not endure.

(Example 2) The same glass material as used in Example 1 was used, and the effective diameter shown in FIG.
The process of forming a 6 mm biconvex lens will be described numerically and specifically with reference to FIGS. The description of the same points as the first embodiment is omitted. Here, after closing the gate valves 18 and 19 in advance, the molding chamber 11 and the unloading chamber 1 are closed.
2 is once evacuated, and then a non-oxidizing gas (N
₂ gas) was introduced. The upper heater 54 and the lower heater 55 were energized to heat the upper molding die 3 and the lower molding die 4 to a temperature corresponding to a glass viscosity of 10 ^8.5 Pa · s.

Then, a molten glass having a viscosity of 10 Pa · s is discharged from the outflow port 22, and the glass lump 24 is placed on the receiving mold 1 in the same manner as in the first embodiment. The lid 14 was closed. In addition, N ₂
And the receiving die 1 is set to a glass viscosity of 10 ⁸ Pa
・ At the same time as the temperature rises to s, the replacement chamber heater 53
And the atmosphere around the glass block 24 becomes 10 ⁴ P
a · s, and the heat of the glass block 24,
Under this heated state, as shown in FIG. 5 (2), the glass block 24c is thermally deformed by its own weight in a state closer to a flat, precision glass product 24d, thereby reducing the glass material 24c. The desired shape was formed.

Thereafter, the energization of the replacement chamber heater 53 is stopped. When the glass material 24c is cooled to 10 ⁴ Pa · s, the inside of the replacement chamber 10 is evacuated and N ₂ is introduced again as in the first embodiment. After such replacement, the receiving mold 1 is moved by means of a suction finger or the like as described above.
From the replacement chamber 10 to the molding chamber 11
And placed on the lower mold 4 heated at a temperature corresponding to a glass viscosity of 10 ^8.5 Pa · s, and a pressure of 4500 N was applied between the molds 3 and 4 for 60 seconds in the same manner as in Example 1. In addition, it was pressed and then cooled, and during cooling, 200
0N pressure is applied, and the movement of the lower mold 4 is changed to a glass molded product 24d.
Following the contraction. Then, the same temperature as in Example 1,
In a manner, precision glassware was removed from the forming chamber via the removal chamber. The result is the same as in the first embodiment.

(Embodiment 3) A step of molding a lens having the same shape as that of the lens formed in Embodiment 1 by using a glass material same as that used in Embodiment 1 by a manufacturing method different from that of Embodiment 1.
This will be specifically described with reference to FIGS. Example 1
Similarly, after closing the gate valves 18 and 19 in advance,
After the interiors of the molding chamber 11 and the take-out chamber 12 are once evacuated, a non-oxidizing gas (N ₂ gas) is introduced and placed, and electricity is supplied to the upper heater 54 and the lower heater 55 so that the upper mold 3 and the lower mold The mold 4 was heated to a temperature corresponding to a glass viscosity of ^108.2 Pa · s.

After melting the glass in the melting furnace,
Molten glass having a viscosity of 10 ^8.5 Pa · s is supplied to outlet 22
Then, as in Example 1, the glass lump 24 was placed in the receiving tray 1 and introduced into the replacement chamber 10. Then, the lid 14 was closed and the glass block 24 was preformed using the preform upper die 2 while flowing N ² in the replacement chamber. In addition, receiving mold 1
In the replacement chamber 10, the heater 5 is set so that the temperature of the upper mold 2 becomes a temperature corresponding to 10 ⁹ Pa · s in viscosity.
1 and 52 were energized to heat the mold and the glass material.

After the preforming, the inside of the replacement chamber 10 is filled with N ₂ gas, and at the same time, in order to avoid excessive cooling,
Energization for heating was performed. And the oxygen concentration is 5pp
m, the gas filling is stopped and the gate valve 18
And the preformed glass (glass material 24a) was moved from the receiving mold 1 in the replacement chamber to the lower mold 4 in the forming chamber 11 in the same manner as in Example 1. At this time, the glass 24a had a temperature corresponding to 10 ⁸ Pa · s in terms of the glass viscosity. Then, at the time of press molding, a pressure of 4500 N is applied to 4
In addition to the mold for 5 seconds, and in the cooling step thereafter, the lower mold 4 is moved to the glass material 2 by the adhesion between the mold and the glass.
4a was followed. Then, at a glass viscosity of 10
^At a temperature corresponding to ¹² Pa · s, the mold was opened, and the glass molded product 24b was taken out in the same manner as in Example 1. The results were also good, as in Example 1.

(Embodiment 4) Here, a lens having the same shape as that of the lens formed in Embodiment 2 is formed using the same glass material used in Embodiment 1, but formed by a manufacturing method different from that of Embodiment 2. Will do. This manufacturing process will be specifically described with reference to FIGS. As in the first embodiment, after closing the gate valves 18 and 19 in advance, the interior of the molding chamber 11 and the take-out chamber 12 is once evacuated, and then a non-oxidizing gas (N ₂ gas) is introduced. The upper heater 54 and the lower heater 55 are energized, and the upper mold 3 and the lower mold 4
^8.2 Heat to a temperature equivalent to Pa · s. And
As in Example 1, after melting the glass, 10 ^8.5 Pa
The molten glass having a viscosity of s is discharged from the outlet 22, the glass block 24 is placed in the receiving tray 1, placed in the replacement chamber 10, the lid 14 is closed, and N ₂ is supplied into the replacement chamber 10. 1 was raised to a temperature corresponding to 10 ⁷ Pa · s in glass viscosity, and at the same time, the replacement chamber heater 53 was energized to change the atmosphere around the glass block 24 to 1 in glass viscosity.
0 ⁴ was heated so that the temperature corresponding to Pa · s, and potential heat of the glass gob 24, under the heating condition, Fig. 5
As shown in (2), the glass block 24 is made flatter and closer to a precision glass product (glass molded product 24b).
The glass material (pre-formed glass) 24a is thermally deformed by its own weight. Then, when the O ₂ concentration in the replacement chamber 10 becomes 5 ppm or less, the supply of N ₂ is stopped,
The gate valve 18 is opened, and the preformed glass 24a is moved from the replacement chamber to the forming chamber and placed on the lower mold 4 in the same manner as in the first embodiment. At this time, the temperature of the glass material 24a was a temperature corresponding to 10 ⁷ Pa · s in glass viscosity. Thereafter, at the time of molding, a pressure of 3000 N is applied to the mold for 30 seconds.
^{Between 10 and} 10 ^12.5 , a pressure of 2000 N was applied to the lower mold 4 to cause the lower mold 4 to follow the shrinkage of the glass material 24a. Thereafter, the mold was opened at a temperature corresponding to a glass viscosity of 10 ¹³ Pa · s, and a precision glass product was taken out in the same manner as in Example 1. The result was as good as in Example 1.

In each of the above embodiments, the replacement chamber 10 is disposed immediately below the outlet 22.
2, the receiving mold 1 may be driven so as to enter and exit obliquely with respect to the replacement chamber so that the receiving mold 1 can be moved under the outlet 22. A plurality of forming apparatuses may be associated with the furnace, and the molten glass may be supplied to the receiving mold of each apparatus in order. Thereby, it is also possible to increase productivity.

Next, a glass material (glass preform)
An embodiment of the present invention will be described in detail with reference to FIGS. Here, for example, at a temperature corresponding to 10 ^{over 2 ~10 4} dPa · s at the glass viscosity, a predetermined amount of molten glass from the melting furnace, the step of taking out separately from the (A), the retrieved molten glass, A step (B) of adjusting the viscosity to a temperature of 10 ⁴ to 10 ¹⁰ dPa · s, and a step of supplying the glass to a mold adjusted to a temperature of a glass viscosity of 10 ¹¹ to 10 ¹⁴ dPa · s ( C) and a step (D) of press-molding the glass with a molding die.

Further, if necessary, after the glass is press-molded with a molding die, when the temperature of the molded glass molded product is a temperature at which the viscosity becomes 10 ¹⁰ to 10 ¹³ dPa · s, Removing (E) from the mold;
(F) cooling the taken-out glass molded article at a temperature gradient of 10 ° C. or more per minute to a temperature of 10 ¹⁴ dPa · s or less. Step (F)
Is a cooling step outside the mold for preventing the glass molded product taken out from being deformed by its own weight due to its viscosity.

Next, preferred embodiments of the above steps (A) to (F) will be described. Step in (A), a glass in a molten state, the glass viscosity of 10 ^@ 2 to 10 ⁴ dPa
A desired amount of glass is taken out at a temperature of s. For example, when glass is dropped in a droplet form from a discharge port (hereinafter, referred to as an orifice) of a melting furnace, a temperature control means is provided near an outlet of the orifice. May be provided, and the temperature of the dripping glass may be controlled within the above range. This temperature range is preferably a temperature at which the viscosity of the glass becomes 10 ^1.6 to ^102.6 dPa · s.

In the step (B), the taken glass is adjusted to a temperature at which the glass has a viscosity of 10 ⁴ to 10 ¹⁰ dPa · s. For example, a cooling gas or the like is blown while the glass dropped from the orifice falls. The temperature may be adjusted according to. This temperature range is 10 ⁶ to 10 ⁸ d in terms of glass viscosity.
The temperature is preferably Pa · s, and more preferably 10 ⁷ to 10 ⁸
The temperature at which dPa · s is more preferable.

In the step (C), the temperature-controlled glass is supplied to a press mold adjusted to a temperature at which the glass viscosity becomes 10 ¹¹ to 10 ¹⁴ dPa · s. Is a glass viscosity of 10 ¹¹ to 10 ¹³ dP
a · s is preferable, and furthermore, 10 ^11.2 to 10
^A temperature at which the pressure becomes ¹² dPa · s is more preferable. The difference between the temperature of the mold and the temperature of the glass to be supplied is preferably equal to or higher than a temperature corresponding to a glass viscosity of 10 ³ dPa · s.

In the step (D), the glass is press-molded by applying a load to the press mold. For example, at least in a region where the shape accuracy to be transferred is required to the mold, the surface of the mold is required. It is advisable to bring glass into close contact and press.

In the step (E), when the viscosity of the molded glass is 10 ¹⁰ to 10 ¹³ dPa · s,
The molded glass is taken out of the mold, for example, at the time of pressing, the glass is deprived of heat by the mold, and if the temperature falls within the above-mentioned temperature range, the glass is peeled from all surfaces of the mold, and is taken out as it is. Good. This temperature range is
A temperature at which the glass viscosity becomes 10 ^10.5 to 10 ^11.5 dPa · s is preferable.

In the step (F), the taken-out molded glass is cooled at a cooling rate of 10 ° C./min or more and the glass viscosity is 1%.
It cools to a temperature below 0 ¹⁴ dPa · s,
This cooling may be realized, for example, using a means such as a cooling gas.

The molding die used in the present invention is prepared in advance by taking into account molding conditions such as temperature, pressure and cooling rate, and the difference in shape between the mold and the molded product determined by the shape of the glass product. It is desirable to use a mold, so that required molding accuracy can be secured. The temperature range of such numerical setting and control depends on the type of glass used,
Needless to say, it is set according to the composition. (Embodiment 5) In order to realize the above-described molding process, for example, a mold having a configuration as shown in FIGS. 8A to 8E is used. Here, reference numeral 101 denotes a glass melting furnace, and 102 denotes an optical glass material (SK12:
103 is an orifice at the outlet thereof, 104 is a glass preform, 105 is a cooling gas, 106 is a lower mold, 107 is an upper mold,
Reference numeral 108 denotes a release plate, 109 denotes a molded lens (glass molded product), and 110 denotes a barrel.

In this embodiment, first, as shown in FIG. 8A, the temperature of the outlet of the orifice 103a is adjusted, and the temperature of the glass 104 dropped from the orifice 103a is set to 1180 ° C. (the glass viscosity is 10 ^2.1 dPa · s). controls to s), taken out by the glass 850mm3 form of droplets, the extracted glass preform 104a, the cooling gas 105 during dropping was cooled to 750 ℃ (10 ^5.8 dPa · s a glass viscosity), FIG. As shown in FIG. 8 (b), it was supplied to the lower mold 106. At this time, the lower mold 106 and the upper mold 107 are previously set at 580 ° C.
(The glass viscosity is controlled to 10 ^11.3 dPa · s).

Immediately after the supply of the glass to the mold, a load of 2 KN was applied for 20 seconds as shown in FIG. The glass surface in contact with the mold during pressing is instantaneously 604
° C, below the temperature at which the mold corrodes. Thereafter, the glass preform was deformed and heat was taken by the upper and lower molds, so that the temperature was 590 ° C. (the glass viscosity was 10 ^10.8 dPa · s) at the end of pressing.

After the pressing, as shown in FIG. 8D, the upper die 107 is raised, and the release plate 10 interlocked therewith.
8, the lower mold 106 and the molded lens 109 were peeled off. At this time, when the lens remains in close contact with the upper mold 107, as shown in FIG.
The upper mold 107 and the lens 109 may be peeled off by using. Thereafter, the lens is removed from the mold, and the glass does not undergo its own weight deformation again due to cooling gas or the like.
It was cooled to 85 ° C. (glass viscosity: 10 ^15.5 dPa · s) in 2 minutes.

The spherical concave lens obtained in this embodiment (FIG. 9)
), Each had 0.5 or less ass, habits, and Newtons, and had a good shape accuracy of 2 or less Newtons in the radius of curvature component.

In this embodiment, the upper and lower dies 10
As for 6, 107, those having a curvature radius of 30.11 mm and a shape having a habit in which the radius of curvature is smaller at the center as shown in FIG. 10 than at the periphery (measured by a Fizeau interferometer) were used. . This is because molding with a mold having no habit causes the molded lens to have a habit, and that amount must be corrected in advance in terms of the mold. (Embodiment 6) FIGS. 11A to 11E show the steps of this embodiment, and FIG. 12 shows a small-diameter convex lens targeted in this embodiment in order to confirm the transfer accuracy. Is shown. Here, the same glass material as that of the fifth embodiment is used, and the glass 112 dropped from the orifice 111a is used.
Temperature of 1320 ° C (10 ^10.6 dPa ·
s), a 25 mm 3 glass is taken out in a droplet form, and the taken out glass preform 112 a is
During the fall, the temperature was controlled to 840 ° C. (glass viscosity: 10 ^4.4 dPa · s) by the heating gas 113. Here, different from the fifth embodiment, the reason why the heating gas is used is that the glass preform 112a is small and the temperature is too low before the glass preform 112a is supplied to the mold.

The removed glass preform 104
When “a” is supplied to the lower mold 114 as shown in FIG. 11B, the lower mold 106 and the upper mold 107 are controlled at 580 ° C. (10 ^11.3 dPa · s in terms of glass viscosity) in advance.

Immediately after the glass was supplied to the mold, a load of 500 N was applied for 10 seconds as shown in FIG. The glass surface that contacts the mold during pressing is 6
The temperature has dropped to 16 ° C., which is below the temperature at which the mold is corroded. Thereafter, the glass preform was deformed and heat was taken by the upper and lower molds, so that the temperature was 595 ° C. (the glass viscosity was 10 ^10.5 dPa · s) at the end of pressing.

After the pressing, as shown in FIG. 11D, the upper die 115 is raised, and the release plate 11 interlocked therewith is lifted.
6, the lower mold 114 and the molded lens 117 were peeled off. At this time, when the lens remains in close contact with the upper mold 115, the upper mold 115 and the lens 117 may be separated by the body mold 118 as shown in FIG. Thereafter, the lens was taken out of the mold, and cooled again to 485 ° C. (glass viscosity: 10 ^15.5 dPa · s) at which the glass did not undergo its own weight deformation by a cooling gas or the like for 2 minutes.

The small-diameter convex lens obtained in this embodiment (see FIG. 12) has asbestos, habit and Newton of 0.5 or less each, and has a good shape accuracy of 2 or less Newtons in the radius of curvature component. Had.

In this embodiment, the upper and lower dies 11
4, 115 have the curvature radii of 3.512 mm and 7.024 mm, and the correction of the peculiarity as in the fifth embodiment is not performed. This is because in the convex lens, as long as the molding conditions of the temperature, the pressure, and the cooling rate are not extremely changed, no peculiarity occurs and only the radius of curvature may be changed. (Embodiment 7) FIGS. 13 (a) to 13 (e) show each step of this embodiment, and FIG. 14 shows the configuration of a meniscus lens targeted in this embodiment in order to confirm transfer accuracy. The shape is shown. Here, the same glass material as that of the fifth embodiment is used, and the glass 12 dropped from the orifice 119a is used.
0 at 1120 ° C (glass viscosity of 10 ^2.3 dPa ·
s), taking out 1430 mm 3 of glass in the form of droplets, and taking out the taken glass preform 120 a
The, 700 ° C. by cooling gas 121 during dropping was cooled (a glass viscosity 10 ^7.1 dPa · s) to, shown in FIG. 13 (b)
As shown in FIG. At this time, lower mold 1
22, the upper mold 123 is previously 570 ° C. (with a glass viscosity of 10
^11.7 dPa · s).

Immediately after the supply of the glass to the mold, a load of 4 KN was applied for 30 seconds as shown in FIG. The glass surface that contacts the mold during pressing is 58
The temperature has dropped to 8 ° C., which is below the temperature at which the mold corrodes.
Thereafter, the glass preform was deformed and heat was taken away by the upper and lower molds. Therefore, the temperature was 585 ° C. (the glass viscosity was 10 ¹¹ dPa · s) at the end of pressing.

After the pressing, as shown in FIG. 13 (d), the upper die 123 is raised and the release plate 12
4, the lower mold 122 and the molded lens 123 were peeled off. At this time, when the lens remains in close contact with the upper mold 123, the upper mold 123 and the lens 125 may be separated by the body mold 126 as shown in FIG. Thereafter, the lens was taken out of the mold, and cooled again to 485 ° C. (glass viscosity: 10 ^15.5 dPa · s) at which the glass did not undergo its own weight deformation by a cooling gas or the like for 2 minutes.

The meniscus lens (see FIG. 14) obtained in this example has an ass, a habit and a Newton of 0.1 mm each.
The number was five or less, and the curvature radius component had a good shape accuracy of two or less Newtons.

In this embodiment, the upper and lower dies 12
The radius of curvature is 112.44 mm,
At 7.04 mm, a shape with a habit where the radius of curvature at the periphery is smaller than that at the center (measured by Fizeau interferometer)
Was used. This is, when molded in a habit-free mold,
This is because the molded lens has a peculiarity, and it is necessary to correct that amount in advance on the surface of the molding die.

[0073]

As described above, the present invention relates to a method for manufacturing a precision glass product from a molten glass in a series of steps including a press forming process. Receiving a predetermined amount of molten glass to be received in a receiving mold, introducing a predetermined amount of molten glass received on the receiving die together with the receiving die into the replacement chamber, and evacuating the replacement chamber by making the replacement chamber airtight. When,
Forming a glass into a required shape in a non-oxidizing gas atmosphere in a replacement chamber or a forming chamber communicating with the replacement chamber, the volatile chamber generated from the glass flowing out of the glass outlet, the replacement chamber or a mold, etc. In addition, the inside of the molding machine is prevented from becoming dirty. Furthermore, since precision glass products are integrated from molten glass, the heat energy of the molten glass can be efficiently used without waste, and a continuous and highly efficient molding operation can be performed.

Further, in a method for manufacturing a precision glass product from a molten glass in a series of steps including press forming, a predetermined amount of molten glass flowing out of a glass outlet of a melting furnace is separated, 10 ^{4 with} its viscosity
10 and adjusting the temperature to be ¹⁰ dPa · s, and supplying the glass to the mold was adjusted to a temperature to be 10 ¹¹ ~10 ¹⁴ dPa · s at the glass viscosity, the glass by the mold press Since it includes the step of molding, even in a relatively short molding cycle, during press molding, thermal damage and deterioration of the mold are avoided, the life of the mold is extended, and a high-precision optical glass molded product is also manufactured. It can be manufactured economically.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an example of an apparatus used for carrying out the present invention.

FIG. 2 is a side view showing an example of a precision glass product formed by the present invention.

FIG. 3 is a side view showing another example of the precision glass product formed by the present invention.

FIG. 4 is a process explanatory view showing a part of the process of the example of the present invention.

FIG. 5 is a process explanatory view showing a part of the process of another embodiment of the present invention.

FIG. 6 is a graph showing temperature control in a forming process in the case of preforming by deformation under its own weight in the present invention.

FIG. 7 is a graph showing temperature control in a molding process in the case of preforming with a mold according to the present invention.

FIG. 8 is a process explanatory view showing an example of temperature adjustment of a molding die in the present invention.

FIG. 9 is a sectional view of a molded product based on the embodiment.

FIG. 10 is a view showing a surface shape of the mold of the above embodiment measured by a Fizeau interferometer.

FIG. 11 is a process explanatory view showing another embodiment of the temperature control of the molding die of the present invention.

FIG. 12 is a sectional view of a molded product based on the above embodiment.

FIG. 13 is a process explanatory view of still another embodiment for adjusting the temperature of the molding die of the present invention.

FIG. 14 is a sectional view of a molded product based on the above embodiment.

FIG. 15 is a view showing the surface shape of the mold of the above embodiment measured by a Fizeau interferometer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Receiving die 2 Upper die for preforming 3 Upper die 4 Lower die 5 Trunk die 6 Bottom plate 7 Hook 10 Replacement room 11 Molding room 12 Extraction room 13 Replacement room chamber 14 Replacement room lid 15 Molding room chamber 16 Extraction room chamber 17 Extraction Chamber lids 18, 19 Gate valve 20 Melting furnace 21 Outflow pipe 22 Outflow port 23 Molten glass 24 Molten glass lump 24a Preformed glass 24b Precision glass products 30 Preformed cylinder 31 Preformed cylinder shaft 32 Loading cylinder 33 Loading cylinder shaft 34 Suction finger 35 Receiving-type driving cylinder 36 Receiving-type driving cylinder shaft 37 Upper-type cylinder 38 Upper-type cylinder shaft 39 Lower-type cylinder 40 Upper-type cylinder shaft 41 Table driving cylinder 42 Table driving cylinder shaft 43 Table 44 Take-out cylinder 45 Take-out cylinder shaft 46 Suction finger 51 Receiving heater 52 Preforming mold heater 53 Replacement chamber heater 54 Upper heater 55 Lower heater 61-69 Seal rubber 101 Glass melting furnace 103a, 111a, 119a Orifice 104, 112, 120 Glass preform 105, 121 Cooling gas 113 Heating gas 106, 114, 122 Lower mold 107, 115, 123 Upper mold 108, 116, 124 Release plate 109, 117, 125 Molded lens 110, 118, 126 Body mold

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Nobuyuki Nakagawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Kohei Nakata 3- 30-2 Shimomaruko, Ota-ku, Tokyo Canon Inside the Company (72) Inventor Akazu Mizuwa 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Hiroe Tanaka 3-30-2, Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) References JP-A-3-228834 (JP, A) JP-A-4-77320 (JP, A) JP-A-61-132526 (JP, A) JP-A-63-162539 (JP, A) JP-A-3-177321 (JP, A) JP-A-1-138144 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C03B 9/00-17/06

Claims (3)

(57) [Claims] 1. A method of manufacturing a precision glass product from a molten glass in a series of steps including a press forming process, wherein a predetermined amount of molten glass flowing out of a glass outlet of a melting furnace is received in a receiving mold. A step of introducing a predetermined amount of molten glass received thereon together with the receiving mold into the replacement chamber; and making the replacement chamber airtight so that the surface of the glass is evacuated.
When the temperature reaches 10 ⁴ Pa · s or more in lath viscosity ,
The vacuuming step and the preforming in a non-oxidizing gas atmosphere
Use a receiving mold with molten glass and an upper mold
The molding atmosphere in the receiving mold and the replacement chamber.
Adjust the ambient temperature so that the glass surface in contact with the receiving mold
Melt due to surface tension on the glass surface opposite to the surface
A process for forming the glass into a substantially spherical shape, and a non-oxidizing agent for communicating the preformed glass with the replacement chamber.
Introduce into the molding chamber in a gas atmosphere
Setting and pressing the glass by applying pressure to the upper mold
And cooling the molded glass while holding it in the molding chamber.
The glass molded product cooled to the required temperature is released from the mold
And producing the precision glass product. 2. Cooling while holding the glass in a mold.
During the cooling, the glass is made to follow the mold during the cooling.
To apply the required pressure to the mold
Is a process that involves the mutual adhesion between the glass and the mold.
The method for producing a precision glass product according to claim 1, wherein: 3. Melting flowing out of a glass outlet of a melting furnace.
The step of receiving a predetermined amount of glass in a receiving mold includes the step of
The molten glass flowing out of the outlet is reduced to a glass viscosity of 10 ^-2 or more.
Step of taking out at a temperature of 10 ⁴ dPa · s and glass
Adjust at a temperature of 10 ⁴ to 10 ¹⁰ dPa · s in viscosity
Process and glass viscosity become 10 ¹¹ to 10 ¹⁴ dPa · s
Supplying the glass to a mold adjusted at a temperature.
The process of releasing the glass molded product from the molding chamber
The temperature of the glass molded article, in its viscosity ¹⁰ 10 10 ¹³
Molds glass molded products when the temperature is dPa · s
The process includes a step of removing the molded glass article from the mold.
Cooled with a gradient, the glass viscosity became 10 ¹⁴ dPa · s.
Characterized by a step of lowering the temperature to below
The method for producing a precision glass product according to claim 1 .