JP6292835B2 - Optical element manufacturing apparatus and optical element manufacturing method - Google Patents

Description

The present invention relates to an optical element manufacturing apparatus and an optical element manufacturing method.

Conventionally, for example, when glass is heated and melted and molded by a mold, molding is often performed under an inert gas atmosphere in order to prevent oxidation of the mold. In this case, the mold containing the molding material is carried into an inert gas replacement chamber, and after evacuation, an inert gas is introduced to replace the inert gas replacement chamber with an inert gas atmosphere. Thereby, the atmosphere in the mold is also an inert gas atmosphere.
For example, in Patent Document 1, a mold set in which an optical element material is arranged is put into an IN port load lock chamber, and after evacuation, nitrogen replacement is performed, and the inside of the mold set is replaced with nitrogen. An apparatus for molding an optical element to be put into a molding chamber is described.
The mold set in the molding chamber is sequentially transported to a heating zone, a press zone, and a cooling zone by a transport unit, and molding is performed.

JP 2010-222221 A

However, the prior art as described above has the following problems.
In the technique described in Patent Document 1, since nitrogen replacement is performed after evacuating the IN port load lock chamber, which is an inert gas replacement chamber, nitrogen suddenly flows into the IN port load lock chamber. As a result, the dust accumulated in the IN port load lock chamber rises, so this floating dust flows into the mold assembly together with nitrogen gas and easily adheres to the surface of the molding material inside and the molding surface of the mold. It has become. For this reason, there exists a problem that dust tends to adhere to the surface of a molded product.
When dust adheres in this manner, particularly when an optical element is molded, there is a problem that the yield of molding is reduced because even if it is a minute amount, it becomes defective when deposited on the optical surface.

The present invention has been made in view of the above problems, and suppresses intrusion and adhesion of dust to the mold assembly when performing an inert gas replacement of the atmosphere inside the mold assembly. An object of the present invention is to provide an optical element manufacturing apparatus and an optical element manufacturing method.

In order to solve the above-described problems, an optical element manufacturing apparatus according to a first aspect of the present invention includes an inert gas replacement chamber that replaces an atmosphere inside a mold assembly that contains an optical material with an inert gas, The inside atmosphere is replaced with an inert gas in an inert gas replacement chamber, the mold assembly moved from the inert gas replacement chamber is accommodated, and the optical element is moved from the optical material by the mold assembly. An optical element manufacturing apparatus comprising a molding chamber for molding, wherein the inert gas replacement chamber accommodates the molding die assembly and performs inert gas replacement, and the chamber is inert. An inert gas supply unit that supplies a gas; a vacuum suction unit that vacuum-sucks the atmosphere of the chamber; and a control unit that controls operations of the inert gas supply unit and the vacuum suction unit. Part is the vacuum While the vacuum suction is performed by the suction unit and the atmosphere in the chamber is discharged, the inert gas is continuously supplied by the inert gas supply unit, and the vacuum suction unit is operated in a state where the chamber is decompressed. It is set as the structure which performs control to stop.

In the said optical element manufacturing apparatus, it is preferable that the said control part starts supply of the said inert gas by the said inert gas supply part, before starting the vacuum suction by the said vacuum suction part.

In the optical element manufacturing apparatus, the control unit preferably supplies the inert gas at a constant flow rate from the inert gas supply unit.

In the optical element manufacturing apparatus, the control unit may control the chamber to be positive pressure by stopping the vacuum suction unit and then supplying the inert gas from the inert gas supply unit. preferable.

According to a second aspect of the present invention, there is provided an optical element manufacturing method comprising: a first step of substituting an atmosphere inside a mold assembly containing an optical material with an inert gas; and the optical material from the optical material by the mold assembly. A second step of moving the mold assembly into a molding chamber in which an element is molded; and an optical element is manufactured by press-molding the optical material softened by heating the mold assembly in the molding chamber. An optical element manufacturing method including the three steps, wherein the first step includes: a workpiece receiving step of storing the mold assembly in a chamber for performing inert gas replacement ; and An inert gas supply step for continuously supplying an inert gas; and a vacuum suction step for vacuum suction of the atmosphere of the chamber, wherein the inert gas supply step is performed until the vacuum suction step is completed. Vacuum suction process and By performing on the line, the method comprising the concurrent supply step of a state where the chamber is depressurized.

In the optical element manufacturing method, the inert gas supply step preferably includes a pre-supply step of supplying the inert gas before starting the vacuum suction step.

In the optical element manufacturing method, it is preferable that the inert gas is supplied at a constant flow rate in the inert gas supply step.

In the optical element manufacturing method, it is preferable that the inert gas supply step includes a post supply step of supplying the inert gas after the vacuum suction step to bring the chamber into a positive pressure.

According to the optical element manufacturing apparatus and the optical element manufacturing method of the present invention, the inert gas replacement is performed by vacuum suction while continuously supplying an inert gas when the atmosphere of the chamber is exhausted. When performing gas replacement, there is an effect that dust can be prevented from entering and adhering to the mold assembly .

It is a typical system block diagram which shows an example of the system configuration | structure of the inert gas replacement apparatus of embodiment of this invention. It is a typical longitudinal cross-sectional view of the shaping | molding die assembly which is an example of the to-be-processed object of the inert gas replacement apparatus of embodiment of this invention. It is a flowchart which shows the flow of the inert gas replacement method of embodiment of this invention. It is typical process explanatory drawing of the inert gas replacement method of embodiment of this invention. It is typical process explanatory drawing of the inert gas replacement method of a comparative example.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
First, an inert gas replacement device according to an embodiment of the present invention will be described.
FIG. 1 is a schematic system configuration diagram showing an example of a system configuration of an inert gas replacement device according to an embodiment of the present invention. FIG. 2 is a schematic longitudinal sectional view of a mold assembly that is an example of an object to be processed of the inert gas replacement device according to the embodiment of the present invention.

As shown in FIG. 1, the inert gas replacement apparatus 1 of the present embodiment is an apparatus for storing an object to be processed and replacing the atmosphere inside and around the object to be processed with an inert gas.
In FIG. 1, the inert gas replacement device 1 is depicted as a single device. However, the inert gas replacement device 1 can be provided adjacent to a device (not shown) that uses the object to be processed after the replacement of the inert gas, or can constitute one device portion of such a device. is there.

Although the to-be-processed object used for the inert gas replacement apparatus 1 is not specifically limited, Below, the mold assembly 15 which press-molds glass and manufactures molded articles, such as an optical element, is demonstrated to an example.
In this case, examples of the apparatus using the mold assembly 15 include a molding apparatus. As a molding apparatus using the mold assembly 15, for example, a heating stage for heating the mold assembly 15, a pressure stage for pressurizing the mold assembly 15 and molding, and cooling the mold assembly 15 are performed. Particularly suitable is a molding apparatus that includes a cooling stage and the like, and a plurality of molding die assemblies 15 are transferred to each of these stages by an appropriate conveying means to perform the respective processes in parallel.

As shown in FIG. 2, the mold assembly 15 includes an optical material 14 that is a glass material that is a material of the optical element, and a mold 10 that press-molds the optical material 14 into a shape of the optical element. .
Examples of types of optical elements that can be manufactured by the mold assembly 15 include lenses, glass flat plates, optical filters, reflection mirrors, prisms, and the like.
In FIG. 2, the optical material 14 is drawn in a spherical shape, but this is an example, and other shapes such as a disk shape are also possible.
The optical material 14 can be manufactured by, for example, molding or cutting from a base material.

The mold 10 includes a lower mold 11, an upper mold 12, and a sleeve 13.
The lower mold 11 is formed of a substantially columnar member having a cylindrical side surface having an outer diameter larger than the outer diameter of the optical element, and a molding for transferring the shape of one optical surface of the optical element to the upper end portion thereof. A surface 11a is formed.
The upper die 12 is formed of a substantially columnar member having a cylindrical side surface having the same outer diameter as the side surface of the lower die 11, and a molding surface that transfers the shape of the other optical surface of the optical element to the lower end portion thereof. 12a is formed.
The sleeve 13 is a cylindrical member having an inner peripheral surface on which side surfaces of the lower mold 11 and the upper mold 12 are slidably fitted.

In the mold 10, the lower mold 11, the upper mold 12, and the sleeve 13 are arranged coaxially in a state where the sleeve 13 externally fits the side surfaces of the lower mold 11 and the upper mold 12, and the upper mold 12 is the sleeve 13. It is movable along the inner peripheral surface.
A space surrounded by the molding surfaces 11a and 12a and the inner peripheral surface of the sleeve 13 constitutes a molding space S for molding the optical material 14 into the shape of the optical element.
The molding space S communicates with the outside through a fitting gap formed between the lower mold 11 and the upper mold 12 and the sleeve 13.
However, in this embodiment, in order to further promote the gas flow between the molding space S and the outside, the sleeve 13 is provided with a through hole 13a.

As the material of the lower mold 11, the upper mold 12, and the sleeve 13, cemented carbide, ceramics, or the like that can withstand the heating temperature and pressure applied during molding can be employed.
For example, portions such as the molding surfaces 11a and 12a that are in contact with the optical material 14 during molding have a configuration in which a release film is formed on the surface of the base material in order to improve mold release properties.
The release film is not particularly limited as long as the release property with respect to the optical material 14 is good. For example, an oxide film such as a Cr (chromium) oxide film or a Ta (tantalum) oxide film, Pt (platinum), or the like. ) -Ir (iridium) film and other metal films, diamond-like carbon and the like can be employed.

Next, the device configuration of the inert gas replacement device 1 will be described.
As shown in FIG. 1, the inert gas replacement device 1 includes a chamber 2, a vacuum suction unit 3, an inert gas supply unit 4, and a control unit 5.

The chamber 2 is a box-shaped body that forms a chamber internal space C having a size capable of accommodating the mold assembly 15 in order to replace the mold assembly 15 with an inert gas. In order to put the mold assembly 15 into and out of the chamber internal space C, for example, a configuration in which a carry-in port provided at an appropriate position so as to be opened and closed can be employed. However, in the present embodiment, the chamber 2 includes a chamber bottom plate 2a and a chamber body 2b that is detachably provided on the chamber bottom plate 2a and forms a chamber internal space C above the chamber bottom plate 2a when mounted. Yes.
For this reason, the mold assembly 15 can be carried in and out with the chamber body 2b removed from the chamber bottom plate 2a and the mold assembly 15 exposed to the outside.
The chamber main body 2b may be attached / detached relative to the chamber bottom plate 2a. For example, the position of the chamber body 2b is fixed, and the chamber bottom plate 2a can be moved together with the mold assembly 15 with respect to the opening below the chamber body 2b to be attached and detached.

  In the following, unless otherwise specified, as shown in FIG. 1, the chamber 2 has a chamber bottom plate 2a and a chamber body 2b in close contact with each other, and a chamber internal space C isolated from the outside is formed inside. It will be explained as a thing.

The internal shape of the chamber body 2b is not particularly limited as long as it has a shape that can accommodate the mold assembly 15 therein and a volume larger than the volume of the mold assembly 15 can be secured. For example, a rectangular parallelepiped shape or a bottomed cylindrical shape may be used.
In the present embodiment, in the following, when a specific numerical example is given, an example in which the volume of the chamber internal space C is 100 cm ³ and the volume of the mold assembly 15 is 10 cm ³ will be described.
The shape and material of the chamber bottom plate 2a and the chamber body 2b are not particularly limited as long as the shape and material can maintain a reduced pressure state in an inert gas replacement step described later.

The vacuum suction unit 3 is a device part that vacuums the atmosphere of the chamber inner space C of the chamber 2 and includes a vacuum pump and the like.
The vacuum suction unit 3 is connected to the other end of the vacuum suction line 3a, one end of which is connected to the chamber 2. From the opening 3c of the vacuum suction line 3a exposed to the chamber internal space C, the chamber internal space C The atmosphere can be vacuumed.
A control valve 3b for opening and closing the vacuum suction line 3a is provided at an intermediate portion of the vacuum suction line 3a.

The inert gas supply unit 4 is a device part that supplies the inert gas G to the chamber internal space C of the chamber 2, and a supply source that holds the inert gas G and a delivery that sends the inert gas G from the supply source. A pump is provided.
The inert gas supply unit 4 is connected to the other end of an inert gas supply line 4a, one end of which is connected to the chamber 2, and an opening 4c of the inert gas supply line 4a exposed to the chamber internal space C. Through this, the inert gas G can be supplied to the chamber internal space C.
An adjusting valve 4b for controlling the flow rate of the inert gas G supplied to the chamber 2 is provided in the middle portion of the inert gas supply line 4a.

The inert gas G supplied by the inert gas supply unit 4 is not particularly limited as long as it is an inert gas in the sense that it does not cause a chemical reaction with the object to be processed at the use temperature of the object to be processed.
For example, when the object to be processed is the mold assembly 15, it does not cause a chemical reaction with the mold 10, the mold release film formed on the molding surfaces 11 a and 12 a, and the optical material 14 at a temperature equal to or lower than the maximum temperature during molding. Any gas can be used. Examples of such inert gas G include nitrogen gas and argon gas.
In this embodiment, the inert gas G employs nitrogen gas.

The control unit 5 is a device part that controls the operations of the vacuum suction unit 3 and the inert gas supply unit 4 based on an operation input from an operation unit (not shown).
Control of the operation of the vacuum suction unit 3 by the control unit 5 includes control of start and stop of the vacuum suction operation of the vacuum suction unit 3, control of the exhaust speed, and control of the opening / closing operation of the control valve 3b. .
Control of the operation of the inert gas supply unit 4 by the control unit 5 includes start and stop control of the supply operation of the inert gas supply unit 4 and control of the flow rate of the inert gas G by the adjustment valve 4b. Yes.
In addition, although illustration is abbreviate | omitted, the inert gas replacement apparatus 1 is provided with appropriate sensors required for the control part 5 to perform such control, for example, a pressure sensor and a flow sensor.

The evacuation speed by the vacuum suction unit 3 controlled by the control unit 5 is controlled so that the flow rate of the inert gas G by the inert gas supply unit 4 does not exceed a certain value, and the chamber internal space C is The oxygen concentration in the inside is set to an allowable limit for preventing oxidation of a release film or the like during molding, for example, 10 ppm or less.
Further, in the present embodiment, when the initial pressure in the chamber internal space C is P0, the pressure in the chamber internal space C is set in advance so that the pressure is reduced to a pressure P2 lower than P0. The pressure P2 is set to a pressure that can be reached in 15 seconds or less from the viewpoint of production quantity. For example, the pressure P2 is set to −80 kPa.

  The apparatus configuration of the control unit 5 may be configured only by hardware that performs the above control, or may be configured by appropriate hardware and a computer including a CPU, a memory, an input / output interface, an external storage device, and the like. The above control function may be realized by executing a control program on a computer.

Next, the operation of the inert gas replacement device 1 will be described focusing on the inert gas replacement method of the present embodiment using the inert gas replacement device 1.
FIG. 3 is a flowchart showing a flow of the inert gas replacement method according to the embodiment of the present invention. FIGS. 4A and 4B are schematic process explanatory views of the inert gas replacement method according to the embodiment of the present invention.

The inert gas replacement method of the present embodiment includes an object accommodation process, an inert gas supply process including a parallel supply process, and a vacuum suction process.
In order to perform the inert gas replacement of the molding space S and the like of the mold assembly 15 by this method, the steps S1 to S8 shown in FIG. 3 are performed using the inert gas replacement device 1 of the present embodiment. Execute according to the flow.

Step S <b> 1 is a step in which the mold assembly 15 is carried into the chamber 2.
In the inert gas replacement device 1, first, the chamber body 2 b is retracted above the chamber bottom plate 2 a to form an empty space on the chamber bottom plate 2 a. Next, the mold assembly 15 is moved onto the chamber bottom plate 2a by means of conveyance such as manpower or a robot, and the chamber main body 2b is mounted on the chamber main body 2b with the chamber main body 2b covered from the receptacle.
As a result, the mold assembly 15 is accommodated in the chamber internal space C of the chamber 2. At this time, the atmosphere in the chamber inner space C is the same as the atmosphere in which the mold assembly 15 is moved.
In addition, depending on the environment where the inert gas replacement device 1 is disposed, the above-described operation can be performed under an atmosphere different from the atmospheric atmosphere or a pressure different from the atmospheric pressure. The description will be made assuming that the operation is performed in an appropriate open atmosphere in a factory building or the like.
Therefore, the atmosphere in the chamber internal space C is an air atmosphere, and the pressure is atmospheric pressure.
Thus, step S1 is completed.

  Step S <b> 1 constitutes an object storing step for storing an object to be processed in a chamber for performing inert gas replacement.

Next, step S2 is performed. This step is a step of starting the supply of the inert gas G by the inert gas supply unit 4.
When the operator inputs the start of inert gas replacement from an operation unit (not shown), the control unit 5 increases the pressure of the inert gas G of the supply source of the inert gas supply unit 4 with a delivery pump, and adjusts the control valve. Control to open 4b is performed. The flow rate of the adjusting valve 4b is set in advance to a flow rate at which the inside of the chamber internal space C is depressurized at a vacuum suction speed described later.
For example, when the exhaust speed of the vacuum suction unit 3 is 30 L / min, the regulation value of the flow rate of the inert gas G by the adjustment valve 4 b is preferably 0.5 L / min.

As shown in FIG. 4A, if the pressure of the atmosphere outside the chamber 2 is, for example, the atmospheric pressure P0, the pressure of the atmosphere in the chamber inner space C is also the atmospheric pressure P0 immediately after the end of step S1. .
When step S2 is executed, the inert gas G supplied through the inert gas supply pipe 4a is introduced into the chamber internal space C in a state where the flow rate is regulated by the regulating valve 4b.
At this time, since the control valve 3b is closed, if the process does not proceed to step S3, the inert gas G flows in until the supply pressure of the inert gas supply unit 4 is balanced, and the pressure in the chamber internal space C is increased. Rises.

Since the inflow rate of the inert gas G from the opening 4c depends on the differential pressure between the atmospheric pressure P0 and the supply pressure, the inflow rate of the inert gas G is maximum at the start of supply and then gradually decreases. .
In this embodiment, supply of the inert gas G is started from the atmospheric pressure P0 by this step, and the flow rate of the inert gas G is regulated to 0.5 L / min or less by the regulating valve 4b. For this reason, for example, compared with the case where the inert gas G is supplied from a state where the chamber internal space C is in a vacuum state, the flow rate of the inert gas G is much smaller, and the atmosphere in the chamber internal space C is agitated. No jet will be generated.
For this reason, for example, even when dust D carried together with the mold assembly 15 accompanies the carry-in of the mold assembly 15 on the chamber bottom plate 2a, the dust D is generated by the inert gas G. Is much less likely to soar.

When the pressure in the chamber internal space C exceeds an appropriate pressure or when a certain time has elapsed since the supply of the inert gas G is started, the control unit 5 executes Step S3. The pressure in the chamber internal space C at this time is P1 (where P1 ≧ P0) below.
Here, P1 = P0 means a case where steps S2 and S3 are executed simultaneously (when the predetermined time is 0).

Step S <b> 3 is a step of starting vacuum suction by the vacuum suction unit 3.
The control unit 5 opens the control valve 3b and causes the vacuum suction unit 3 to start vacuum suction. At this time, the control part 5 does not change the control with respect to the inert gas supply part 4 and the regulating valve 4b.
Step S3 is complete | finished above.
When this step is executed, as shown in FIG. 4B, the atmosphere g in the chamber internal space C is sucked from the opening 3c and exhausted to the outside of the chamber internal space C through the vacuum suction line 3a. start.
Thereby, the pressure in the chamber internal space C starts to decrease.

Next, step S4 is performed. This step is a step of reducing the pressure in the chamber 2 by performing vacuum suction and supplying the inert gas G in parallel.
The control unit 5 continues the vacuum suction by the vacuum suction unit 3 and the supply of the inert gas G by the inert gas supply unit 4 until the pressure in the chamber internal space C reaches a predetermined pressure P2.
In the present embodiment, since the flow rate of the inert gas G is lower than the exhaust speed of the vacuum suction unit 3, the atmosphere g in which the air atmosphere in the chamber internal space C and the inert gas G are mixed gradually becomes the vacuum suction line. The gas is discharged through 3a and replaced with the inert gas G. Further, the pressure in the chamber internal space C gradually decreases from the pressure P1 in step S3.
Further, since the chamber inner space C and the molding space S communicate with each other, in the molding space S as well, as in the chamber inner space C, the atmospheric atmosphere is exhausted and gradually replaced with the inert gas G. Will go down.

In this way, as the discharge of the atmosphere g proceeds, the oxygen concentration in the chamber inner space C and the molding space S gradually decreases, and when reaching the pressure P2, the oxidation of the release film and the like during molding is prevented. Or less than the allowable limit. For example, at the exhaust speed and the flow rate of the inert gas G in the above specific example, when this step is performed for about 15 seconds and P2 = −80 (kPa) is reached, the oxygen concentration becomes 10 ppm or less.
In this way, when this step is completed, the oxygen concentration initially present in the chamber internal space C becomes below the allowable limit.
When the pressure in the chamber internal space C reaches the pressure P2, step S4 is terminated and the process proceeds to step S5.

In this step, since the chamber internal space C is gradually depressurized, the flow rate of the inert gas G gradually increases according to the pressure difference from the supply pressure of the inert gas supply unit 4 at first. To do. However, since the flow rate of the inert gas G is regulated to a predetermined value or less by the regulating valve 4b, a flow that has a small energy and disturbs the chamber internal space C is unlikely to occur. For this reason, possibility that the dust D will soar by the inert gas G becomes small.
Even if it rises, since there is a flow exhausted from the chamber internal space C, the dust D that has risen is exhausted to the outside together with the atmosphere g over time.
As a result, the soared dust D is prevented from remaining in the molding space S of the mold assembly 15 and adhering to the molding surfaces 11a and 12a.

Step S5 is a step of stopping vacuum suction by the vacuum suction unit 3.
The controller 5 stops the vacuum suction of the vacuum suction unit 3 after closing the control valve 3b. However, the control part 5 does not change the control with respect to the inert gas supply part 4 and the regulating valve 4b.
This is the end of step S5.
When this step is executed, the inert gas G continues to be supplied to the chamber inner space C. However, since the inert gas G is not discharged to the outside, the pressure in the chamber inner space C starts to rise.

Next, step S6 is performed. This step is a step in which the supply of the inert gas G is continued to bring the chamber 2 to a predetermined positive pressure.
In the present embodiment, the control unit 5 continues the supply of the inert gas G by the inert gas supply unit 4 until the pressure in the chamber internal space C becomes a positive pressure larger than the atmospheric pressure P0.
However, the reason why the chamber inner space C is set to a positive pressure is to prevent the external atmosphere from flowing when the mold assembly 15 is transferred.
For example, when the inert gas replacement device 1 is adjacent to the molding device or provided in a part of the molding device, the environment for transferring the mold assembly 15 is a molding chamber, and the external atmosphere is It becomes the atmosphere of the molding room. In this case, the pressure in the chamber internal space C only needs to be positive with respect to the pressure in the molding chamber, and it is not essential to make the pressure positive with respect to the atmospheric pressure P0.
When the pressure in the chamber internal space C becomes a predetermined positive pressure, step S6 is completed.

Next, step S7 is performed. This step is a step of stopping the supply of the inert gas G by the inert gas supply unit 4.
The control unit 5 performs control to close the regulating valve 4b and stops the supply of the inert gas G from the inert gas supply unit 4.
Thereby, the inert gas replacement in the chamber internal space C is completed.

The above steps S <b> 2 to S <b> 7 constitute an inert gas supply process for continuously supplying the inert gas G to the chamber 2.
Said step S3-S5 comprises the vacuum suction process which vacuum-sucks the atmosphere of the chamber 2. As shown in FIG.
For this reason, said step S4 comprises the parallel supply process which makes the chamber 2 the state decompressed by performing in parallel with a vacuum suction process until a vacuum suction process is complete | finished.
Furthermore, between step S2 and step S3 constitutes a pre-feeding process for feeding the inert gas G before starting the vacuum suction process.
Step S <b> 6 constitutes a post-supply process in which an inert gas G is supplied to bring the chamber 2 to a positive pressure after the vacuum suction process is completed.

Next, step S8 is performed. This step is a step of transferring the mold assembly 15 from the chamber 2.
The transfer destination of the mold assembly 15 is, for example, a molding apparatus or a molding chamber that performs molding.
Thus, when the mold assembly 15 is transferred, the pressure in the molding space S is higher than the external atmosphere P2 in step S7. Therefore, the chamber internal space C is opened to the external atmosphere. However, the external atmosphere does not immediately flow into the molding space S.
In this way, when the transfer of the mold assembly 15 is completed, for example, a molding operation or the like is required in a state where the oxygen concentration in the molding space S is below the allowable limit and the inert gas G is filled. Can be started according to.
At this time, since the dust D is also discharged by the inert gas G replacement in the molding space S, the occurrence of molding defects due to the dust D is prevented.

Here, the operation as described above in the present embodiment will be described in comparison with a comparative example.
FIGS. 5A and 5B are schematic process explanatory views of an inert gas replacement method of a comparative example.

The inert gas replacement device 100 of the comparative example shown in FIGS. 5A and 5B only opens and closes the inert gas supply line 4a, instead of the regulating valve 4b of the inert gas replacement device 1 of the present embodiment. The control valve 40b for performing the above is provided, and the following operation is performed in a state where the supply pressure of the inert gas supply unit 4 is set to the pressure P2.
Hereinafter, a description will be given focusing on differences from the above embodiment.

In the inert gas replacement device 100, after performing step S1 in the same manner as in the above embodiment, as shown in FIG. 5A, vacuum suction is performed from the vacuum suction line 3a with the control valve 40b closed. To form a vacuum state of pressure Q1. The pressure Q1 is, for example, −100 kPa.
Thereby, the air atmosphere A in the chamber internal space C is exhausted, and the oxygen concentration in the chamber internal space C and the molding space S of the mold assembly 15 becomes less than the allowable limit.
When the pressure Q1 is reached, the vacuum suction by the vacuum suction line 3a is stopped. Thereby, the control valve 3b is closed.

Next, as shown in FIG. 5B, with the regulating valve 3b closed, the regulating valve 40b is opened, and the inert gas G is supplied into the chamber internal space C.
In this comparative example, since the supply pressure of the inert gas supply unit 4 is set to P2, the inert gas G is ejected from the opening 4c in accordance with the pressure difference between Q1 and P2, so that the internal space of the chamber A jet is generated in C.
Thereby, if the dust D accumulates on the chamber bottom plate 2a, the dust D will rise. At this time, since the control valve 3b is closed, there is no flow from the chamber internal space C to the outside. For this reason, the soared dust D floats in the chamber inner space C and enters the molding space S of the mold assembly 15 or adheres to the molding surfaces 11a and 12a.
As described above, when molding is performed using the mold assembly 15 in which the dust D enters and adheres, molding defects due to the dust D occur.

  As described above, according to the inert gas replacement device 1 and the inert gas replacement method of the present embodiment using the inert gas replacement device 1, the inert gas G is discharged when the atmosphere of the chamber 2 is exhausted. Vacuum suction is performed while continuously supplying, and inert gas replacement is performed while reducing pressure. For this reason, since the pressure difference between the supplied inert gas G and the chamber 2 is smaller than when the inert gas G is supplied after evacuation to a high vacuum, the replacement of the inert gas is performed. When performing, the penetration | invasion of dust D to the shaping | molding die assembly 15 and adhesion can be suppressed.

In the above description of the embodiment, the chamber bottom plate 2a and the chamber main body 2b are in close contact with each other and the chamber inner space C is sealed during the inert gas replacement. If the external atmosphere is an inert gas G atmosphere, it may be communicated with the external atmosphere as long as it does not hinder vacuum suction.
For example, when the chamber 2 is provided so as to communicate with a molding chamber into which the inert gas G is introduced in advance, the inert gas replacement can be performed even if the chamber 2 is not completely sealed. It is.

  All the constituent elements described above can be implemented by appropriately changing or deleting combinations within the scope of the technical idea of the present invention.

DESCRIPTION OF SYMBOLS 1 Inert gas replacement apparatus 2 Chamber 3 Vacuum suction part 3a Vacuum suction line 3b Control valve 4 Inert gas supply part 4a Inert gas supply line 4b Control valve 5 Control part 10 Mold 11 Lower mold 11a, 12a Molding surface 12 Upper mold 14 Optical material 15 Mold assembly (object to be processed)
100 inert gas replacement device C chamber internal space D dust g atmosphere G inert gas S molding space

Claims (8)

An inert gas replacement chamber for replacing the atmosphere inside the mold assembly containing the optical material with an inert gas;
The inside atmosphere is replaced with an inert gas in the inert gas replacement chamber, the mold assembly moved from the inert gas replacement chamber is accommodated, and the optical element is moved from the optical material by the mold assembly. A molding chamber for molding,
An optical element manufacturing apparatus comprising:
The inert gas replacement chamber is
A chamber for accommodating the mold assembly and performing inert gas replacement;
An inert gas supply unit for supplying an inert gas to the chamber;
A vacuum suction section for vacuum suction of the atmosphere of the chamber;
A control unit for controlling operations of the inert gas supply unit and the vacuum suction unit;
With
The controller is
While the vacuum suction unit performs vacuum suction and discharges the atmosphere in the chamber, the inert gas is continuously supplied by the inert gas supply unit, and the vacuum suction is performed while the chamber is decompressed. Control to stop the part,
Optical element manufacturing equipment. The controller is
2. The optical element manufacturing apparatus according to claim 1, wherein supply of the inert gas by the inert gas supply unit is started before starting vacuum suction by the vacuum suction unit. The controller is
The optical element manufacturing apparatus according to claim 1, wherein the inert gas is supplied from the inert gas supply unit at a constant flow rate. The controller is
4. The control according to claim 1, wherein after the vacuum suction unit is stopped, the inert gas is supplied from the inert gas supply unit to control the chamber to a positive pressure. The optical element manufacturing apparatus according to Item. A first step of replacing the atmosphere inside the mold assembly containing the optical material with an inert gas;
A second step of moving the mold assembly into a molding chamber for molding an optical element from the optical material by the mold assembly;
A third step of producing an optical element by press-molding the optical material softened by heating the mold assembly in the molding chamber;
An optical element manufacturing method comprising:
The first step includes
A workpiece storage step of storing the mold assembly in a chamber for performing inert gas replacement;
An inert gas supply step of continuously supplying an inert gas to the chamber;
A vacuum suction step of vacuuming the atmosphere of the chamber;
Have
The inert gas supply step includes
An optical element manufacturing method, comprising: a parallel supply step of bringing the chamber into a decompressed state by performing in parallel with the vacuum suction step until the vacuum suction step is completed. The inert gas supply step includes
The optical element manufacturing method according to claim 5, further comprising a pre-feeding step of feeding the inert gas before starting the vacuum suction step. In the inert gas supply step,
The optical element manufacturing method according to claim 5, wherein the inert gas is supplied at a constant flow rate. The inert gas supply step includes
The optical element according to any one of claims 5 to 7, further comprising a post-supplying step of supplying the inert gas to bring the chamber into a positive pressure after completion of the vacuum suction step. Manufacturing method.

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