JP2002114525A - Method for molding optical element - Google Patents

Abstract

(57) [Abstract] (With correction) [Problem] By fine pressure adjustment of the ineffective surface from a higher temperature range, even in a shape easily cracked or a molded product made of a glass material, it is possible to improve the shape accuracy of a peripheral portion of the molded product. Provided is a method for molding an optical element, which can prevent cracks generated in a cooling step while maintaining the same. SOLUTION: When a predetermined temperature is reached after cooling is started,
First, the drive source 14 is used so that the surface shape of the molded product 6 does not collapse.
Is pushed out, and the lower mold member 2 and the lower mold outer peripheral member 3
Is pressed from below to apply pressure to the molded product 6. Then, when the temperature is slightly lowered, while gradually lowering the pressure of the driving source 14 and pushing out the driving source 12, the pressure applied to the lower die outer peripheral member 3 is maintained while maintaining the pressure applied to the lower die member 2. Only the pressure is gradually reduced so that it becomes zero at a predetermined temperature. Furthermore, when the temperature is lowered to a predetermined temperature by cooling, the drive source 12 is retracted to release the pressure applied to the lower mold member 2 for the first time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for forming an optical element obtained by pressing a glass material between heated upper and lower molds.

[0002]

2. Description of the Related Art Conventionally, when an optical element is obtained by pressing a glass material between heated upper and lower molds, pressing the upper and lower molds and then proceeding to a cooling step. To prevent deterioration, apply the required press pressure during cooling, but at this time, since the upper and lower dies each continue the press operation integrally, the same pressure is applied to the entire surface of the molded product. Was added.

Japanese Patent Application Laid-Open No. Hei 5-319839 discloses a molding die which is effective for preventing the molded product from cracking. A configuration that is divided into a flat processing portion and a flat processing portion is disclosed.

[0004]

However, when the same pressure is applied to the entire surface of the molded product during cooling, there is a problem that many cracks occur depending on the shape of the molded product, which hinders mass productivity. In particular, a shape having a thin protruding portion in the periphery of the molded product, a convex meniscus shape, or a lens having a relatively large diameter is liable to be cracked from the peripheral portion during cooling.

That is, during cooling, the thin portion around the molded product cools down quickly, and the thick portion does not cool down easily. Therefore, the force applied to the molded product concentrates on the thin portion and the portion is restrained by the mold. Smooth shrinkage of the molded product is hindered, and cracks are likely to occur. Also, cracks are likely to occur in a glass material having a large linear expansion coefficient or a relatively low strength.

Therefore, a method disclosed in Japanese Patent Laid-Open Publication No. Hei 5-319839 is also conceivable. In this case, a material having a larger linear expansion coefficient than a mold member forming a thick portion is used for a mold member forming a thin portion. However, since a material having a larger linear expansion coefficient generally tends to have a lower hardness, a material having a larger linear expansion coefficient is often unsuitable as a material for pressing an optical element, and is not practical.

[0007] In addition, the tendency of cracking differs depending on the shape of the molded product. In order to effectively prevent cracking, when it is desired to adjust the pressure applied to the peripheral portion of the molded product during cooling, this method is used. Since it depends only on the difference between the linear expansion coefficients of the two mold members, the pressure cannot be controlled,
There was a problem that we would occur. This is mainly caused by the difference in linear expansion coefficient between the mold and the molded product, but the difference increases as the temperature increases, so depending on the shape of the molded product, the temperature increases from the high temperature range to the periphery of the molded product. That is, it is necessary to adjust such pressure.

Further, when the peripheral shape of the molded article is used as a reference plane for positioning, it is impossible to control the pressure applied to the peripheral part of the molded article during cooling. was there.

Therefore, the present invention has been made based on the above circumstances, and a first object of the present invention is to provide a molded article made of a glass material, which is apt to cause cracks, and a shape accuracy of a peripheral portion of the molded article. Generated in the cooling process while maintaining
It is an object of the present invention to provide a method for forming an optical element for preventing cracking.

[0010] The present invention also provides a method for molding an optical element capable of preventing the molded product from cracking, as in the first invention, even in a molded product having a shape in which cracks are more likely to occur. Aim.

It is a further object of the present invention to provide a method of molding an optical element according to the second aspect of the present invention, which does not degrade the accuracy of the optically effective surface and further enhances the effect of preventing cracks. And

[0012]

In order to achieve the above object, according to the present invention, a glass material is press-formed between heated upper and lower molds, and cooled while holding the molded article between the upper and lower molds. In a molding method of an optical element in which a mold is opened to take out a molded product, the viscosity of the glass upon cooling is 10%.
During the temperature changes of up to ¹⁰ to 10 ¹² poises, at least,
The condition is set so that the pressure applied to the non-effective surface of the glass is smaller than the pressure applied to the surface including the optically effective surface of the glass.

Accordingly, a pressure sufficient to prevent the deterioration of the surface accuracy is applied to the molding surface of the optically effective surface, and a pressure sufficient to maintain the shape accuracy is applied to the non-effective surface, and the pressure at which no crack is generated. And the restraint on the shrinkage of the periphery of the molded article by the mold can be minimized.

In order to achieve the above object, according to the present invention, a glass material is press-molded between heated upper and lower molds, cooled while holding the molded article between the upper and lower molds, and then the mold is opened. In a method for molding an optical element, a molded article is taken out, and while the temperature of the glass during cooling changes from 10 ¹⁰ to 10 ¹² poise, pressure is applied to the surface including the optically effective surface of the glass. The condition is set to release the close contact between the ineffective surface and the mold, and cooling is further performed.

In this way, in a high temperature region where the coefficient of linear expansion of the glass is large, the area where the molded product is substantially in contact with the mold can be minimized. Can be minimized.

Further, in order to achieve the above object, according to the present invention, in the above invention, when releasing the close contact state between the ineffective surface of the glass and the mold, the close contact state of the upper and lower surfaces of the glass is substantially simultaneously. It is characterized by being released.

Thus, in the above invention, the area in which the molded article is substantially in contact with the mold can be made substantially equal between the upper and lower surfaces, so that the surface accuracy of the optically effective surface can be undesirably deteriorated. In addition, since the upper and lower surfaces are released from the close contact state in the high temperature range, the restraint of the mold from shrinking around the molded product can be further reduced.

[0018]

FIG. 1 is a block diagram showing an embodiment of the present invention.
A detailed description will be given of the configuration of an apparatus showing a method of forming an optical element in FIGS. 1 and 2 show the first embodiment, and FIGS. 3 to 5 show the second embodiment, respectively.

(First Embodiment) In FIG. 1, a through-hole is formed on the center axis of a body die 4 constituting an outer shell of a molding die in a state where the body die 4 is vertically penetrated. Have been.
Of the through holes, the upper through-hole is slidably inserted in the up-down direction in a state in which the upper mold member 1 formed in a cylindrical shape is fitted. In the center of the lower surface, there is formed a molding surface for pressing the glass material, transferring a desired shape to the surface, and forming an optical function surface.

A drive source 10 (piston-cylinder mechanism) for generating a press pressure applied to the glass material is disposed above the upper die member 1. The movable portion of the drive source 10 A pressing pressure is applied to the glass material by being pushed downward through the upper shaft 11.

A heater 7 for heating the upper mold member 1 is provided in the upper part of the body mold 4, and a sensor (not shown) for measuring the temperature near the molding surface is provided on the upper mold member 1. Z)
The upper mold member 1 is further cooled from a N ₂ gas supply source (not shown) through an N ₂ ejection pipe (not shown).

On the other hand, a lower die outer peripheral member 3 formed in a ring shape is inserted into the lower through hole of the body die 4 in a fitted state so as to be slidable in the vertical direction. Further, the lower mold member 2 formed in a cylindrical shape is inserted into the through hole formed on the central axis of the lower mold outer peripheral member 3 so as to be slidable in the vertical direction in a fitted state. I have. Further, on the upper surface of the lower mold member 2, a molding surface for forming an optical function surface (effective surface) by transferring a desired shape to the lower surface of the glass material is formed. On the upper surface, a molding surface for transferring a desired shape around the lower surface of the glass material to form a positioning surface (ineffective surface) is formed.

A drive source 12 (piston-cylinder mechanism) is provided below the lower mold member 2, and its movable part is in contact with the lower surface of the lower mold member 2 via a lower shaft 13. . A drive source 14 (a second-stage piston / cylinder mechanism) is provided below the drive source 12, and its movable portion avoids the drive source 12 so that the outer peripheral lower shaft 17 can be moved.
In addition, the lower die member 2 and the lower die outer peripheral member 3 are brought into contact with the lower surfaces of the lower die member 2 and the lower die peripheral member 3 via a connection member 16 having a contact member 15 at the tip.

The drive source 14 raises the lower die member 2 and the lower die outer peripheral member 3 in order to prevent the surface and shape of the molded product 6 from being collapsed in the cooling process after the press deformation operation is completed. The drive source 12 similarly increases the surface accuracy of the effective surface of the molded product 6 in the cooling process after the press deformation operation is completed. In order to prevent collapse, only the lower mold member 2 is pushed upward to apply pressure to the molded product 6.

A heater 8 for heating the lower die member 2 and the lower die outer peripheral member 3 is provided below the body die 4, and the lower die member 2 measures the temperature near the molding surface. Sensors (not shown) are installed.
₂ N ₂ jet pipe (not shown) from gas supply source (not shown)
To cool the lower mold member 2.

An opening 4a is formed in the side surface of the body die 4. For example, a glass material is supplied from the right side of the opening 4a to the inside of the molding die via a conveying member (not shown). Is done. Further, the molded product 6 that has been molded is taken out from the inside of the molding die via the conveying member. Also,
A heating member (not shown) is inserted from the left side of the opening 4a to heat the glass material.

The heaters 7 and 8 provided inside the above-mentioned body mold 4 are connected to independent temperature controllers (not shown), and are disposed on the upper mold member 1 and the lower mold member 2, respectively. The temperature is detected and controlled by the sensor.

Next, a procedure for molding a lens using the mold having the above-described configuration will be described. First, the driving source 10 is pulled in, the upper mold member 1 is slid upward with respect to the body mold 4, and is released from the lower mold member 2. In this state, the glass material is supplied onto the molding surface of the lower mold member 2 from the right side of the opening 4a of the body mold 4 via a conveying member (not shown). The upper mold member 1 and the lower mold member 2 are adjusted to a temperature corresponding to a predetermined molding condition.

When the glass material is supplied onto the molding surface of the lower mold member 2, a heating member (not shown) is inserted from the left side of the opening 4a of the body mold 4 to heat the glass material. . When the upper mold member 1, the lower mold member 2 and the glass material reach a predetermined temperature, the heating member retreats to the left outside of the body mold 4, and immediately drives the drive source 10 to perform an operation of pushing out the glass material. The molding surface of the upper mold member 1 is brought into contact with the upper surface, and press molding is performed by applying a pressing pressure to the glass material.

When the flange portion 1a of the upper mold member 1 comes into contact with the upper surface of the body mold 4 and the deformation operation of the glass is completed, the process proceeds to a cooling step, and the upper mold member 1 and the lower mold member 2 are respectively connected to the N ₂ ejection pipe. (Not shown) by the N ₂ gas supplied
Its cooling is promoted.

When the temperature reaches a predetermined temperature after the start of cooling, the drive source 14 is first pushed out so that the surface shape of the molded product 6 does not collapse, and the lower mold member 2 and the lower mold outer member 3 are moved.
Is pressed from below to apply pressure to the molded product 6. Then, when the temperature is slightly lowered, while gradually lowering the pressure of the driving source 14 and pushing out the driving source 12, the pressure applied to the lower die outer peripheral member 3 is maintained while maintaining the pressure applied to the lower die member 2. Only the pressure is gradually reduced so that it becomes zero at a predetermined temperature. Furthermore, when the temperature is lowered to a predetermined temperature by cooling, the drive source 12 is retracted to release the pressure applied to the lower mold member 2 for the first time.

Thereafter, when the driving source 10 is pulled in to move the upper die member 1 upward, the molded product 6 'is
It is taken out from the right side of the opening 4a of the barrel mold 4 via a transport member (not shown).

Here, the molding conditions will be described in detail using a lens used in a camera as a specific example. Heavy crown glass (refractive index: 1.5
8, Abbe number: 59.4, transition point: 506 ° C.), lower surface side convex R = 16 mm, upper surface side convex aspheric surface (approximate R =
16), spherical outer diameter: φ14 mm, center thickness: 4.0 m
m, the thickness of the outer protruding portion: 0.7 mm, and a biconvex lens that uses the shape of the protruding portion as a reference plane for positioning (not necessary up to the accuracy as an optical functional surface) is formed.

First, when the temperature of the upper mold member 1 and the lower mold member 2 is 470 ° C. (corresponding to 10 ^15.2 poise), a glass material is charged, and the glass material is heated by the heating member as described above. In this state, when the temperature of the upper and lower molds 1 and member 2 becomes 580 ℃ (10 ^{9. 0} poises equivalent), yet, becomes a temperature of the glass material also 580 ° C. (10 ^9.0 poises equivalent), The upper mold member 1 was press-molded so that the pressure finally applied to the molded product 6 became 15 MPa (megapascal), and the molding surface of the mold was transferred to glass.

Next, cooling was started.
When the pressure reaches 0 ^9.8 poise), the pressure applied to the upper mold member 1 is kept as it is, and the lower mold member 2 and the lower mold outer peripheral member 3 apply a pressure of 10 MPa to the entire molded product 6. Next, at 550 ° C. (corresponding to ^10.3 poise), the drive source 12 is pushed out of the effective surface of the molded product 6 ′ so as to maintain a pressure of 10 MPa, and the peripheral portion of the molded product 6 ′ is ineffective. The drive source 14 is operated to gradually lower the pressure from 10 MPa on the surface.

510 ° C. (corresponding to ^10.2 poise)
At that point, the pressure applied to the non-effective surface is reduced to zero, and thereafter, cooling is performed while maintaining the effective surface pressure,
When the temperature reached 490 ° C. (corresponding to 10 ^13.5 poise), the pressure of the lower mold member 2 was also released. Then, at 470 ° C (10 ^15.2
Poise), raise the upper mold member 1, open the mold,
The molded product 6 'was taken out.

When 500 shots of the lens were formed by a series of operations as described above, no crack was generated in the molded product, and the variation in the thickness of the protruding portion was 10 μm (micrometer). ), And a molded product with sufficient accuracy as a reference plane for positioning can be obtained.

By the way, in the conventional method in which the same pressure is continuously applied to the entire surface of the molded article at the time of cooling, many occurrences have occurred, and molding has been difficult.

(Second Embodiment) In FIG. 3, a ring-shaped upper die outer peripheral member 23 is fitted in a through hole on the upper side of a body die 4 along the vertical direction. The upper mold member 21 formed in a cylindrical shape is fitted into a through hole formed on the center axis of the upper mold outer peripheral member 23 in a vertically Are slidably inserted along. On the lower surface of the upper die member 21, a molding surface for transferring a desired shape to the upper surface of the glass material to form an optical function surface (effective surface) is formed. Is formed with a molding surface for transferring a desired shape to the periphery of the upper surface of the glass material to form an ineffective surface.

A driving source 10 for generating a press pressure applied to the glass material is disposed above the upper die 1, and the driving source 10 is connected to the upper die 21 via an upper shaft 19. Connected to the upper surface of the

A driving source 27 is provided on the upper shaft 19, and the driving source 27 fixes the positional relationship with the upper die member 21 via the outer peripheral upper shaft 28 while the upper die outer member 2 is fixed.
When the upper surface of 3 is pushed downward, a pressing pressure is also applied to the vicinity of the glass material. Furthermore, the molding surface of the upper die outer peripheral member 23 can be retracted from the molding surface of the upper die member 21 in the direction opposite to the press by the retraction operation of the drive source 27.

The driving source 27 is used to press the molded product 2 during pressing.
6 is press-deformed, and in the cooling process, in the high temperature region, only the upper mold outer member 23 is retracted upward, so that the molding surface of the upper mold outer member 23 and the upper surface of the periphery of the molded product 26 'are separated. The mold is released to release the close contact state.

On the other hand, as in the first embodiment, a lower die outer peripheral member 24 and a lower die member 22 are inserted into the lower through hole of the body die 4, and the upper surface of the lower die member 22 is formed on the lower die member 22. Is formed with a molding surface for forming an optical function surface (effective surface) by transferring a desired shape to the lower surface of the glass material. In this case, a molding surface for transferring a desired shape to form an ineffective surface is formed.

Further, the pull-in operation of the drive source 14
The molding surface of the lower mold outer peripheral member 24 can be retracted from the molding surface of the lower mold member 22 via the contact member 18, the connecting member 16, and the outer peripheral lower shaft 17.

In the cooling process after the press deformation operation is completed, the drive source 14 first moves the lower mold member 22 and the lower mold outer peripheral member 24 in order to prevent the surface and shape of the molded product 26 from collapsing. The upper surface of the lower mold outer member 24 is pushed upward to apply pressure to the molded product 26. Thereafter, only the lower mold outer peripheral member 24 is retracted downward while still in a high temperature range, and the molding surface of the lower mold outer member 24 is formed. Then, the lower surface of the peripheral part of the molded product 26 'is released from the mold to release the close contact state.

The rest of the configuration is the same as in the first embodiment, and a detailed description will be omitted.

Next, a procedure for molding a lens using the mold having the above-described configuration will be described. However, since the procedure is almost the same as that of the first embodiment, overlapping parts will be omitted.

First, the driving source 10 is pulled in, and
The upper mold member 21 and the upper mold outer peripheral member 23 are slid upward with respect to the body mold 4 and are released from the lower mold member 22. In this state, the glass material is supplied onto the molding surface of the lower mold member 22, and the glass material is heated by a heating member (not shown).

When the upper mold member 21, the lower mold member 22 and the glass material reach a predetermined temperature, the pressing is started. First, the driving source 27 is pushed out and the forming surface of the upper mold outer peripheral member 23 is changed. After the molding surface of the upper mold member 21 is aligned, the drive source 10 is pushed out to perform the press molding.

The flange portion 21a of the upper die member 21
Abuts on the upper surface of the body mold 4 and when the deformation operation of the glass is completed, the process moves to a cooling step, and the upper mold member 21 and the lower mold member 22 are supplied through N ₂ ejection pipes (not shown), respectively. Cooling is promoted by the N ₂ gas.

After the cooling is started, when the temperature reaches a predetermined temperature, the driving source 14 is controlled so that the surface shape of the molded product 26 does not collapse.
Is pushed out, the lower mold member 22 and the lower mold outer peripheral member 24 are pressed from below, and pressure is applied to the molded product 26.
Next, when the temperature reaches a predetermined temperature in the high-temperature range, the driving source 12 is pushed out, and while the pressure applied to the lower mold member 22 is maintained, the driving operations of the driving source 27 and the driving source 14 are performed almost simultaneously. Then, the molding surfaces of the upper die outer peripheral member 23 and the lower die outer peripheral member 24 are released from the upper and lower peripheral portions of the molded product 26 'almost simultaneously. Further, cooling is performed in this state, and when the temperature decreases to a predetermined temperature, the drive source 12 is pulled in and the pressure applied to the lower mold member 22 is released for the first time.

Thereafter, the driving source 10 is pulled in to move the upper die member 21 and the upper die outer peripheral member 23 upward, and the molded product 26 'is taken out. Here, similarly to the first embodiment, detailed molding conditions will be described using a lens used in a camera as an example.

A lanthanum-based glass (refractive index:
1.68, Abbe number: 54.9, transition point: 562 ° C.), lower surface side convex aspheric surface (approximate R = 15 mm), upper surface side concave R40, outer diameter: φ16 mm, optical aperture φ14 mm,
A convex meniscus lens having a center thickness of 2.5 mm is formed.

First, when the temperature of the upper mold member 21 and the lower mold member 22 is 530 ° C. (corresponding to 10 ^14.9 poise), a glass material is charged, and the glass material is heated by the heating member as described above. Temperature of the upper mold member 21 and a lower mold member 22 in this state is turned 625 ° C. (10 ^9.0 poises equivalent), yet, the temperature of the glass material also 625 ℃ (10 ^{9. 0}
(Equivalent to poise), the drive source 27 is set to 1000 N
(Newton's) force and then press operation is started.
Was press-molded so that the pressure applied was 15 MPa (megapascal), and the molding surface of the mold was transferred to glass.

Next, cooling was started.
(Equivalent to 0 ^9.6 poise), the pressure applied to the upper die member 21 is kept as it is, and the lower die member 22 and the lower die outer peripheral member 24 apply a pressure of 10 MPa to the entire molded product 26. Next, at 585 ° C. (corresponding to 10 ^10.9 poise), the driving source 12 is pushed out to the effective surface of the molded product 26 ′ so as to maintain a pressure of 10 MPa, and the molded product 2
By driving the drive source 27 and the drive source 14 almost simultaneously with respect to the non-effective surface in the peripheral portion of 6 ', the close contact between the upper die outer member 23 and the lower die outer member 24 is almost simultaneously performed. To release. Continue cooling in this state,
When the temperature reached 540 ° C. (corresponding to ^10.4 poise), the pressure of the lower mold member 22 was also released. Then, at 530 ° C (10
Upper die member 21 and upper die outer peripheral member 2 at ^14.9 poise)
3, the mold was opened, and the molded product 26 'was taken out.

By performing a series of operations as described above, lens molding was performed 500 shots, and the surface accuracy was good.
A molded article could be obtained without any occurrence.

Incidentally, also in this case, in the conventional method in which the same pressure is continuously applied to the entire surface of the molded article at the time of cooling, the occurrence of cracks frequently occurred, and molding was difficult.

As described above, in the case of a molded product in which the shape accuracy of the non-effective surface in the peripheral portion of the molded product is relatively rough, the close contact between the peripheral portion of the molded product and the mold can be completely achieved in a high temperature range during cooling. By releasing it, the effect on prevention of cracking is further increased.

(Other Embodiments) In the first embodiment, at the time of cooling, the same pressure is once applied to the entire surface of the molded product, and then the pressure on the non-effective surface of the peripheral portion is gradually reduced to zero. After that, the pressure on the effective surface is released.However, since the pressure on the peripheral portion can be freely controlled in this way, the method of applying the pressure on the peripheral portion may be other than this, for example, at a certain temperature, the pressure on the ineffective surface may be reduced. The pressure may be held in half and released together with the pressure on the effective surface.In other words, the pressure on the non-effective surface should be lower than the effective surface, and depending on the shape and glass type of the molded product, how to apply the pressure May be changed.

In the second embodiment, once during cooling,
After applying the same pressure to the entire surface of the molded product, the adhesion state of the ineffective surface of the peripheral part is released, but for example, when the adhesion force between the mold and the glass is strong, even if no pressure is applied during cooling The effect of the present invention can be obtained as long as the close contact state of the non-effective surface of the peripheral portion is released.

In the present embodiment, the mold member is
Although it is a two-body type that includes the effective surface and the non-effective surface,
For example, the non-effective surface is further made into a double ring structure to form a three-body structure, and the pressure of the non-effective surface portion is changed in two stages,
You may make it release | release.

In the present embodiment, the peripheral portion is formed in a thin lens shape. However, the present invention is not particularly limited to this shape. This method is effective because the restrained state of the mold can be weakened (substantial molded article diameter can be reduced). Further, it goes without saying that the present invention can be applied not only to lenses but also to optical elements having various shapes such as prisms.

[0063]

As described above, according to the present invention,
The viscosity of the glass when cooled is 10^Ten-10 ¹²Warm to Poise
Surface that includes at least the optically effective surface of the glass during the power change
Pressure on the non-effective surface of glass rather than pressure on
From the higher temperature range to set conditions so that
Small pressure adjustment on the non-effective surface of
The shape of the peripheral part of the molded product
Prevent cracks generated during the cooling process while maintaining accuracy
And the effect is great.

Further, according to the present invention, during the temperature change of the glass at the time of cooling from 10 ¹⁰ to 10 ¹² poise, the pressure on the surface including the optically effective surface of the glass is maintained while the pressure is not applied. By releasing the close contact between the effective surface and the mold and further cooling, the mold can be restrained against the non-effective surface, so that it can be completely prevented from being in the high temperature range. Therefore, the method can not only be effective in improving the surface accuracy of the effective surface, but also can achieve a greater effect in preventing cracking. Therefore, it is possible to mold a molded product or a glass type having a shape in which cracks are more easily generated, and the effect is large.

According to the present invention, when the ineffective surface of the glass and the mold are released from close contact with each other, the upper and lower surfaces of the glass are released substantially simultaneously. Since only a state in which only the surface is restricted from the mold does not occur, the surface accuracy of the effective surface is not adversely affected. Therefore, it is possible to obtain a molded product having good surface accuracy without cracks, and it is possible to obtain a more effective molding method.

[Brief description of the drawings]

FIG. 1 is a front view (cross-sectional view) showing a method of forming an optical element and a configuration of an apparatus according to a first embodiment of the present invention, in which a press deformation operation is completed and a cooling process is started. It is the figure which showed the vicinity of the mold immediately before.

FIG. 2 is a front view (cross-sectional view) showing a configuration of an apparatus showing a method of molding an optical element according to a first embodiment of the present invention, in which cooling is performed from the entire lower surface side of the molded product during cooling. FIG. 3 is a view showing the vicinity of a molding die in a state where the molding die is pressed.

FIG. 3 is a front view (cross-sectional view) showing a configuration of an apparatus showing a method for molding an optical element according to a second embodiment of the present invention, in which press deformation operation is completed, and the process proceeds to a cooling step. It is the figure which showed the vicinity of the mold immediately before.

FIG. 4 is a front view (cross-sectional view) showing a configuration of an apparatus showing a method for molding an optical element according to a second embodiment of the present invention, in which pressure is applied from the entire lower surface side of a molded product during cooling. FIG. 3 is a diagram showing the vicinity of a molding die in a state where the molding is performed.

FIG. 5 shows a second embodiment according to the present invention.
FIG. 2 is a front view (cross-sectional view) showing a configuration of an apparatus showing a method of molding an optical element, showing a vicinity of a molding die in a state in which close contact with upper and lower peripheral portions of upper and lower surfaces of a molded product is released during cooling. FIG.

[Explanation of symbols]

 1, 21 Upper die member 1a, 21a Flange part 2, 22 Lower die member 3, 24 Lower die outer peripheral member 4 Trunk die 4a Opening 5 Support substrate 6, 6 ', 26, 26' Molded product 7, 8 Heater 10, 12, 14, 27 Drive source 11, 19 Upper shaft 13 Lower shaft 15, 18 Contact member 16 Connection member 17 Outer lower shaft 23 Upper die outer member 28 Outer upper shaft

Claims (3)

[Claims] 1. A glass material is press-formed between heated upper and lower molds, and cooled while holding the molded product between the upper and lower molds.
Then, in the molding method of the optical element in which the mold is opened and the molded product is taken out, the viscosity of the glass at the time of cooling is 10 ^10-
The optics is characterized in that during a temperature change up to 10 ¹² poise, at least the pressure applied to the non-effective surface of the glass is lower than the pressure applied to the surface including the optically effective surface of the glass. Element forming method. 2. A glass material is press-molded between heated upper and lower molds, and cooled while holding the molded article between the upper and lower molds.
Then, in the molding method of the optical element in which the mold is opened and the molded product is taken out, the viscosity of the glass at the time of cooling is 10 ^10-
During the temperature change up to 10 ¹² poise, it is necessary to further cool the glass while maintaining pressure on the surface including the optically effective surface while releasing the close contact between the ineffective surface of the glass and the mold. Characteristic method of forming optical element. 3. The method according to claim 2, wherein, when releasing the close contact between the ineffective surface of the glass and the mold, the close contact between the upper and lower surfaces of the glass is released almost simultaneously. Optical element molding method.