JP2001010831A - Molding mold for glass optical element and production of glass optical element using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for press molding an optical glass, capable of excellently carrying out the release of glass from a molding mold. SOLUTION: This glass press molding method comprises a process for preparing a molding mold including an upper mold 11 and a lower mold 12 having molding surfaces and provided with rough faces 20 at parts except an optical function forming zones in the molding surfaces, a process for feeding a softened glass material to the molding surface of the lower mold 12, a process which is a process for press molding the fed glass material, molds a material to transfer unevenness on the rough faces to the faces of the pressed glass and, after the passage of a time to cause a position displacement of the unevenness on the rough faces from the unevenness transferred to the glass by difference in coefficient of linear expansion between the molding mold and the glass, relatively separates the upper mold from the lower mold and a process for taking out the pressed glass from the molding mold. When the glass shrinks after the pressing, the unevenness transferred to the glass is stranded on the unevenness of the rough faces and open air is introduced from a gap formed thereby to between the molding surfaces of the molds and the glass to excellently release the glass from the molds.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for precision press-molding glass optical elements such as lenses and prisms which does not require grinding and polishing after press-molding a glass material. And a method of manufacturing a glass optical element with improved characteristics.

[0002]

2. Description of the Related Art Conventionally, as a method of molding optical glass, particularly an optical lens, a press molding method in which softened glass is pressed and molded is known. In the press molding method, a glass material is heated to a predetermined temperature (the viscosity of glass is 10
^Then , the molten glass is heated to a temperature of ^7.5 to 10 ¹¹ poise to soften it, or the viscosity of the molten glass is adjusted to the predetermined temperature, and then supplied to a mold having an upper mold and a lower mold. Next, the softened glass material is pressed by the forming surfaces of both molds, and a glass having a shape along the forming surfaces is formed. Then, the glass is cooled while maintaining its state until the temperature of the glass reaches its transition point (about 10 ^13.4 poise) or lower, and then the upper mold and the lower mold are separated from each other, and the pressed glass can be taken out. To do.

[0003] In the above-mentioned glass press-forming method, particularly in the press-forming method of a glass having a concave surface, there has conventionally been pointed out a problem of mold release of the glass when the mold is released after the press. As shown in FIG. 11, in the process of cooling the glass after pressing, a closed space S under negative pressure may be generated between the upper mold 1 and the glass G. This is caused by the fact that the coefficient of linear expansion of the glass is greater than that of the mold and therefore the glass shrinks relatively along the molding surface of the mold. When the closed space S of such a negative pressure is generated between the upper mold and the glass, the adhesion between the upper mold and the glass increases, and the glass temporarily moves to the upper mold when the mold is separated after pressing. May be permanently or permanently attached. For this reason, there is a problem that the glass later falls from the upper mold and the optical surface thereof is damaged, or the conveyance of the glass is hindered. A similar problem may occur in forming a convex glass having a brim-shaped flat portion around the periphery.

[0004]

In order to address such a problem, several methods have been proposed in the prior art. As a typical method, there is a method in which a physical force is applied to glass adhered to an upper mold and vibration is applied to a mold to release the mold. However, in this method, since a physical force or vibration is applied to the glass at a temperature around the transition point, there are problems such as impairing the surface accuracy of the glass and causing cracks.

[0005] Also, there are known a method of reducing the pressure around the glass when the mold is separated, and a method of setting the side having a tighter radius of curvature on both sides of the glass to the upper mold. However, the former method requires a large-scale structure for reducing the pressure of the surrounding atmosphere, and the latter method has a problem that the shape of glass that can be produced by the method is limited.

Further, the present inventors have formed a plurality of depressions on the molding surface of the mold, and when the glass shrinks after pressing, the protruding portions corresponding to the depressions get over the depressions, whereby the glass with respect to the mold is formed. A technique for improving mold release has been disclosed (JP-A-3-218932). However, in the above method, it is not easy to form a dent on the molding surface of the mold, and the degree of processing causes the dent of the mold to become a resistance during shrinkage of the glass. Concentrating and distorting the surface accuracy,
It may cause cracks.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a method for press-molding an optical glass that can satisfactorily release a mold from a mold without using a complicated shape of the mold and a complicated apparatus configuration.

Another object of the present invention is to reduce the surface accuracy of the glass when releasing the glass from the molding die,
An object of the present invention is to provide a method for press-molding optical glass that does not cause cracks.

[0009]

SUMMARY OF THE INVENTION The present invention relates to a molding die for forming a glass optical element by pressing a glass material softened on a molding surface, comprising an upper die and a lower die facing each other. In the present invention, the upper mold and the lower mold each have an optical function forming region for forming an optical function surface of the glass optical element on a molding surface thereof, and A rough surface is formed in a region other than the optical function forming region, and the maximum height of the unevenness represented by Rmax on the rough surface is a region other than the optical function forming region in the lower mold. Is larger than the maximum height of the unevenness represented by Rmax.

When the glass material is pressed by using the molding die, the rough surface is transferred to the surface of the glass optical element to be molded. Upon shrinkage of the glass optical element after the press,
The transferred irregularities ride over the irregularities on the rough surface of the mold,
As a result, a small gap communicating with the outside is formed between the mold and the glass optical element. The outside air can enter between the molding surface of the molding die and the glass from this small gap, and the release of the glass from the molding die becomes good. In this case, since the rough surface is formed on the molding surface with a predetermined range, it is possible to avoid the occurrence of stress at one point of the glass optical element when the glass contracts, and to prevent cracks and glass caused by the stress. Surface distortion can be prevented.

In this case, preferably, the rough surface is a rough surface having a maximum height Rmax of 0.1 μm or more.

Preferably, the upper mold has a molding surface including a plane perpendicular to the optical axis of the glass optical element to be molded.

It is preferable that the upper mold has a molding surface in which the optical function forming region is convex.

The lower mold has a maximum height Rmax of 0.1.
It is preferable that a rough surface of μm or less is formed.

Further, the lower mold is provided with a maximum height Rmax0.0.
The mirror surface may be 3 μm or less.

Further, it is preferable that a rough surface of a molding surface of the upper mold and / or the lower mold is formed at a position of the molding surface corresponding to an outer peripheral portion of the glass to be removed.

The present invention also relates to a method for producing a glass optical element by press-molding a glass material in a mold including an upper mold and a lower mold having opposing molding surfaces. The method of the present invention includes the following steps. That is,
In a region other than the optical function forming region on the molding surface of the upper mold, a maximum height Rmax larger than a maximum height Rmax of a region other than the optical function forming region on the molding surface of the lower mold.
Performing the press forming with a forming die having a rough surface having the following, transferring the rough surface to the glass material, cooling the forming die and the glass after the press forming, and after cooling, A step of relatively separating the upper mold and the lower mold,
Removing the molded glass from the molding surface of the lower mold.

In this case, the maximum height of the upper mold is 0.2
It is preferable that the surface has a roughness of at least μm.

It is preferable that a rough surface having a maximum height Rmax of 0.1 μm or less is formed in a region other than the optical function forming region of the lower mold forming surface.

Further, the area other than the optical function forming area of the molding surface of the lower die may be constituted by a mirror surface having a maximum height Rmax of 0.03 or less.

It is preferable that the upper mold has a molding surface including a plane perpendicular to the optical axis of the glass optical element to be molded.

Preferably, the upper mold has a molding surface in which the optical function forming region is convex.

Further, it is preferable that the rough surface is formed at a position of the forming surface corresponding to an outer peripheral portion of the glass to be removed.

In the step of relatively separating the molding surfaces of the upper mold and the lower mold, the temperature of the glass after the pressing is lower than a temperature corresponding to a viscosity of 10 ¹² poise, and It is preferably performed when the temperature is higher than -50C.

Further, it is preferable to perform a step of removing the rough surface forming portion.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. In the embodiment described below, the present invention will be described along an optical lens forming method using a mold for forming a meniscus lens. FIG. 1 is a side sectional view of a molding die to which the present invention is applied. As shown in the figure, the molding die 10 includes an upper die 11 and a lower die 12 which are arranged to face each other by being installed on a press (not shown). A glass preform, that is, a glass material preformed for press molding is arranged between the upper die 11 and the lower die 12, and is pressed on the molding surfaces 11a and 12a of both dies to obtain a desired shape. Obtain an optical lens. After press molding, the lens is taken out of the mold 10 and its outer peripheral end is cut for centering.

The upper mold 11 and the lower mold 12 have molding surfaces 11a and 12a facing each other. The molding surface 11a of the upper mold is formed into a convex surface, and the molding surface 12a of the lower mold is formed.
Is formed in a concave surface, and pressing is performed using these molding surfaces to form a meniscus lens along the shape. In order to form a meniscus lens with high surface accuracy,
The molding surfaces 11a and 12a are highly precision machined. After rough grinding and fine grinding with diamond wheel,
By performing finish polishing, these molding surfaces can be finished to a smooth optical mirror surface. In the present invention, a predetermined portion may be roughened after finishing, or after rough grinding or rough grinding, subsequent steps (fine grinding and finish polishing) can be performed only on the optical function forming region. In the practice of the present invention, the material of the mold 10 is not particularly limited. Use a cemented carbide base with a thin film such as a noble metal alloy or titanium nitride on the molding surface, or use a silicon carbide or cemented carbide base with a carbon-based thin film such as hard carbon or diamond-like carbon. be able to.

In the present invention, the upper mold 1
A rough surface 20 is formed on one molding surface 11a. Here, the molding surface refers to a surface on which the shape is to be transferred to glass. FIG. 2 shows a state in which the molding surface of the upper mold is viewed in a plan view, where the region of the rough surface 20 with respect to the molding surface 11a is clearly shown. 3 and 4 are a side cross-sectional view and an enlarged view of a main part of the molding die 10 in a state after the glass press. Here, a corresponding positional relationship of the rough surface 20 with respect to the pressed glass G is shown. Have been. Hereinafter, details of the molding surface of the upper die will be described with reference to these drawings.

As shown in these figures, an annular rough surface 20 is formed on the molding surface 11a of the upper mold 11 along the periphery thereof. The rough surface 20 is formed from the peripheral end of the molding surface 11a to a predetermined region inside, and the arrangement of the rough surface 20 on the molding surface is determined by the relationship with various dimensions of the lens G after pressing. Can be. That is, as shown in FIG. 3, in the optical lens G, a predetermined range from the center thereof is an optically functional area indicated by the effective diameter r, and the rough surface 2
0 is formed outside the corresponding region on the molding surface 11a (hereinafter, referred to as an optical function forming region). Therefore, the unevenness of the rough surface 20 transferred to the lens side by the press does not affect the optically functional surface. Further, it is not necessary to form a rough surface over the entire region other than the optical function forming region, and the arrangement shape is not limited to the above-mentioned annular shape, but may be appropriately block-shaped or dotted in an island shape radially located from the center of the molding surface. You can choose. In addition, the lens outer diameter K after centering in the figure indicates the outer diameter of the lens after cutting for centering.

The rough surface 20 is formed on the molded surface 1 after the finish polishing.
The peripheral portion of 1a can be formed by processing with a diamond grindstone having a large grain size. Also,
In the manufacturing process of the molding surface, the rough surface may be formed by not performing fine grinding or final finishing polishing on a peripheral portion thereof. At this time, the uneven shape of the rough surface is not particularly limited, and may be an island shape or a stripe shape.
In a preferred embodiment, the surface roughness Rmax of the optical function forming region of the molding surface is 0.03 μm or less, but 0.015 μm or less depending on the required optical characteristics.
Furthermore, it can be 0.007 μm or less.

The rough surface refers to a surface having a surface roughness Rmax larger than the surface roughness Rmax of the optical function forming region on the same molding surface, and preferably has a surface roughness Rmax of more than 0.1 μm, and more preferably Rmax0. .2 μm or more is more preferable. Regarding the specific action of the rough surface,
This will be described in the following molding procedure.

Next, the procedure of molding the optical lens according to the present invention using the mold will be described. 5 to 7
FIG. 2 is a process chart showing a procedure of press molding according to one embodiment of the present invention. Prior to the pressing step, the mold 10 and the supplied glass preform are preheated in a non-oxidizing atmosphere to a predetermined temperature, for example, near the softening point of the glass preform. In one embodiment, the mold 10 can be preheated to a temperature lower than the temperature of the glass preform to be supplied, ie, non-isothermal (eg, preheating the glass to a temperature at which its viscosity is 10 ⁷ poise). In case,
Preheat the mold to the temperature required to bring the viscosity of the glass to 10 ⁹ poise). However, the present invention is preferably used even when the mold is preheated isothermally with the glass preform.

In the first step of molding, the preheated glass preform G is supplied onto the molding surface 12a of the lower mold 12 separated from the upper mold 11 (FIG. 5). Preferably, a floating plate (not shown) that floats and transports the glass preform G by an air current can be used. Here, the glass composition of the supplied glass preform G is determined in consideration of the type and use of the glass to be molded, chemical durability, thermal expansion coefficient, the relationship with the material of the molding die, and the like. Further, as the glass preform, a sphere, a disk, a flat spherical shape having a spherical surface or an aspherical surface, or another shape is employed, and a cold-polished or hot-formed glass is employed. It will be apparent to those skilled in the art that the press forming method of the present invention is applicable regardless of the type and manufacturing method of such a glass preform.

Next, the lower die 12 is raised relatively to the upper die 11 (of course, the upper die 11 may be lowered) and supplied to the molding surface 12a of the lower die. The glass preform G is pressed at a predetermined pressure (for example, 100 kg).
/ Cm ² ) (FIG. 6). The distance between the molding surfaces and the pressure of the press are determined according to the required shape of the optical glass. By the press, the glass preform G
As shown in the drawing, is rolled along both forming surfaces to have a desired shape (hereinafter, a pressed glass is referred to as a formed glass). Here, it should be noted that the rough surface 20 is formed around the molding surface 11a of the upper die as described above. Due to the deformation of the glass preform G by the press, the periphery of the lens reaches the region of the molding surface on which the rough surface 20 is formed, and therefore, the periphery of the molded glass is
Unevenness corresponding to the unevenness of the rough surface is transferred.

The press by the mold is maintained for a predetermined time, during which the mold 10 and the formed glass G are cooled. At this time, the cooling of the mold and the glass can be started before the start of the press forming, or simultaneously with the start of the press forming, or after the start of the press forming. In relation to the operation of the present invention, this cooling step is performed by the difference in linear expansion coefficient between the molding die 10 and the molded glass G, and the irregularities of the rough surface 20 and the irregularities transferred to the molded glass G are reduced. Is performed so as to cause displacement. Such misalignment occurs during pressing, particularly when the press pressure is reduced, when the press pressure is released, or when the separation step is started after the release of the press pressure, when the lower die is May occur during the release step, or may occur the same as during the removal of the formed glass.

The step of relatively separating the upper mold and the lower mold comprises:
It is preferable that the heat treatment is performed after the molded glass has been cooled to a viscosity of 10 ¹² poise or more. On the other hand, if mold release is performed after the molded glass is cooled to a temperature lower than (Tg-50) ° C., the cycle time of the molding is increased and the productivity is reduced, so that the temperature is higher than (Tg-50) ° C. Preferably, the separation is performed at a temperature. Accordingly, the separation is preferably performed at a temperature corresponding to (Tg-50) ° C. to 10 ¹² poise, and more preferably at a temperature corresponding to (Tg−30) ° C. to 10 ¹² poise. According to experiments by the inventors, when mold release is performed at a viscosity lower than this or at a temperature higher than a temperature corresponding to obtaining the viscosity, the surface accuracy of the formed glass may not be sufficient.

Then, after cooling so as to cause displacement, that is, after displacement between the glass and the mold,
Alternatively, after a state occurs, the lower mold 12 is lowered to separate the molds from each other (FIG. 7). Here, the state in which the misalignment between the glass and the molding die is a state in which misalignment occurs when the press pressure is reduced or released, or when the formed glass is released from the mold. Say. At this time, at the time of starting the separation, a position shift occurs due to the action of the rough surface, and the optical contact state is released at least in this portion. Is performed well. This will be conceptually described with reference to FIG. FIG. 5A shows the molding surface 11a immediately after pressing and the molded glass G near the rough surface 20 on the molding surface 11a.
FIG. 6B shows a state after the formed glass G has relatively shrunk with respect to the upper mold 11 in the cooling step. As shown in FIG. 3A, the irregularities on the rough surface 20 are transferred to the surface of the glass G formed at the time of pressing. Since the viscosity of the formed glass G is increased by cooling, the shape of the transferred unevenness is maintained, but due to the relative shrinkage or expansion of the formed glass G due to the difference in linear expansion coefficient between the mold and the formed glass. The periphery of the molded glass G moves toward the center, and the irregularities of the molded glass G ride on the irregularities of the molding surface 11a.
A gap is formed between the formed glass and the forming surface. The phenomenon that such a gap occurs is called displacement. The gap allows gas to flow between the vicinity of the center of the molded glass G and the molding surface 11a, and the optical contact state between the glass and the mold in the uneven portion is released, and the mold of the molded glass G is released. Is good. At this time, since the Rmax of the portion other than the optical function forming region of the upper die is larger than the Rmax of the portion other than the optical function forming region of the lower die, the gap between the glass and the molding surface when the positional shift occurs is increased. The mold becomes larger, and the adhesion between the glass and the mold can be made smaller in the upper mold. Therefore, it is preferable to cool the glass and the mold so as to cause displacement.

As described above, in the step of separating the upper mold and the lower mold, it is preferable to form the rough surface at least on the upper mold in order to prevent the formed glass from sticking to the upper mold. At this time, it is not necessary to form a rough surface on the opposing lower mold, but if the rough surface is formed, the mold releasability at the time of removing the molded glass from the lower mold is improved.

However, in order to prevent the glass formed on the upper mold from sticking in the separating step of the upper mold and the lower mold, the releasability of the upper mold and the glass is set to be equal to that of the lower mold and the glass. Therefore, it is important to make the surface roughness Rmax larger on the rough surface formed on the upper mold than on the rough surface formed on the lower mold. Further, for example, as a preferred embodiment, when the rough surface having a surface roughness Rmax of 0.1 μm or less is formed on the lower mold, the surface roughness Rma is formed on the upper mold.
When forming the rough surface of x0.2 μm or more, the lower mold may be a mirror surface having a surface roughness Rmax of 0.03 μm or less without forming the rough surface, and a rough surface may be formed only on the upper mold.

Further, regardless of the surface roughness Rmax of the rough surface, at the start of the separation step of the upper mold and the lower mold, a positional shift occurs only between the upper mold and the glass, and
At the start of the step of taking out the glass formed from the lower mold, the cooling step may be performed so that a displacement occurs between the lower mold and the glass.

The glass G formed on the lower mold 12 is sucked by a suction pad (not shown) and is carried out of the mold 10. Here, the present invention is not limited to the case where the mold for taking out the molded glass is a lower mold.For example, the glass material is press-molded with left and right molding dies arranged so that the optical axis is horizontal, and the glass material is molded. The present invention can also be applied to a press molding method for an optical element in which glass is taken out from a predetermined molding die on the left or right. Unloaded molded glass G
In a later step, the outer peripheral end is cut to perform centering. In the present embodiment, the unevenness of the rough surface transferred to the formed glass has a part thereof remaining around even after the centering, but this is outside the effective diameter of the formed glass. , Without impairing its optical function.

[0042]

EXAMPLE In this example (Examples 1 to 5), the glass material had a linear expansion coefficient of 7 to 1 in the temperature range of the cooling step.
A glass material of 5 × 10 ⁻⁶ / ° C. was used. [Example 1] In the apparatus configuration shown in the above embodiment, a meniscus lens was actually formed. The molded lens has a lens effective diameter (optical functional surface) of 18 mm on the top surface,
The outer diameter of the lens is 23 mm, and the outer diameter (lens outer diameter after the centering) is 2
Finished to 0mm. In Examples, silicon carbide (coefficient of linear expansion:
4.2 × 10 ^-6 / ° C), and the outer diameter of the upper and lower molds is 2
5 mm. The upper mold surface was finished to have a surface roughness of 70 Å Rmax or less, and then roughened to a surface roughness of 0.2 to 0.4 μm Rmax with a diamond grindstone having a larger particle size outside the effective diameter. At that time, processing was performed so that a step did not occur at the boundary with the finished surface (optically functional surface). This is to prevent the step at the boundary from being caught when the lens contracts and the surface accuracy is not impaired. On the other hand, the lower mold had its entire molding surface finished to a surface roughness of 70 Å Rmax or less. Prior to molding, the molding surface was covered with a carbon-based thin film.

A glass material of a glass preform was prepared and press-molded at a pressure of 100 kg / cm ² with the above-mentioned mold (at this time, the glass had a diameter of about 22 mm on the molding surface of the upper mold).
mm, the outer diameter of the press becomes 23 mm), cooling was performed while maintaining this for a predetermined time, and when the temperature became equal to or lower than the glass transition point, the lower mold was lowered to release the mold. .

When a large number of lenses were molded under the above conditions, when the lower mold was lowered after pressing, the lenses did not stick to the upper mold and the mold was reliably released. The surface accuracy of the molded lens was good, and there was no defect in appearance. This lens was centered in a post-process after molding, and finished to a predetermined final outer diameter of 20 mm.

On the other hand, for comparison, the above glass preform was subjected to press molding in the same manner using an upper die having a surface roughness Rmax of not more than 70 Å without forming a rough surface. In most lens presses, when the lower mold descends, the lens sticks to the upper mold and falls after a few seconds to a few tens of seconds. Some of the dropped lenses cracked.

Example 2 A lens was manufactured in the same manner as in Example 1 except that the material of the molding die was tungsten carbide (linear expansion coefficient: 4.7 × 10 ⁻⁶ / ° C.).
The same results as in Example 1 were obtained. Also, for comparison,
When a lens was manufactured in the same manner as in the comparative experiment in Example 1, similar results were obtained.

[Embodiment 3] In the embodiment 1, a rough surface was formed on the molding surface of the upper die in a region corresponding to the outside of the effective diameter (18 mm) of the lens. However, as shown in FIG. In the example, the rough surface 20 was formed at a position corresponding to the outside of the lens outer diameter (20 mm) after the centering of the lens. Other conditions were the same as those in Example 1, and many lenses were press-molded. Also in this case, the release of the lens from the upper mold was good, and no release failure occurred. In the case of this embodiment, the irregularities of the rough surface transferred to the lens are outside the outer diameter of the lens after centering, and thus are completely removed after centering.

Example 4 A biconvex lens having a flat surface portion 30 as shown in FIG. 10 was molded according to the press molding method of the present invention. The flat part 30 functions as a holding part when being incorporated into the optical system. Conventionally, even when a lens having such a shape is press-molded, since the flat portion is in close contact with the molding surface when the lens is contracted,
The releasability was poor. In the embodiment, the flat portion of the upper die 11 with respect to the flat portion 30 is formed to have a surface roughness of 0.5 μm Rmax.
To form a rough surface 20, and pressed under the same conditions as in the previous example. As a result, when the mold was separated after pressing, the lens was successfully released without sticking to the upper mold.

Example 5 A lens was manufactured in the same manner as in Example 4, except that the material of the mold was tungsten carbide (linear expansion coefficient: 4.7 × 10 ⁻⁶ / ° C.).
The same results as in Example 1 were obtained.

At this time, it is possible to form a rough surface on the flat portion of the lower mold 12, but in order to make the adhesion of the lens to the lower mold higher than that of the upper mold,
The surface roughness is preferably set to 0.1 μmRmax or less.

The embodiments and examples of the present invention have been described with reference to the drawings. However, it is apparent that the present invention is not limited to the above-described embodiments and examples, and that changes, improvements, and the like can be made based on the claims. In addition, the method of the present invention can be used for forming a microlens, which does not require centering after press molding. Other well-known methods for improving the release of glass from the upper mold can be used in combination with the present invention.

[0052]

As described above, according to the present invention, the irregularities on the rough surface formed on the molding die are generally transferred to the glass by press molding, and the irregularities reduce the irregularities on the mold side when the glass shrinks after pressing. For the ride, a slight gap is formed between the molding surface of the mold and the glass, from which gas flows between the mold and the glass. As a result, the glass is easily released without adhering to the mold.

Since the rough surface is formed over a predetermined range of the molding surface of the mold, the rough surface does not cause stress at one point of the glass, and may cause cracks and decrease in surface accuracy. Absent.

According to the present invention, the lens is made of Tg-5.
Even when the temperature is 0 ° C. or more, the mold is satisfactorily released when the mold is separated, so that the optical glass can be molded in a short cycle without any trouble.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a molding die to which the present invention is applied.

FIG. 2 is a plan view of a molding surface of an upper mold according to the present invention.

FIG. 3 is a side sectional view of a molding die in a state after a glass press.

FIG. 4 is an enlarged view of a main part of FIG. 3;

FIG. 5 is a process chart showing a procedure of press molding according to one embodiment of the present invention.

FIG. 6 is a process chart showing a procedure of press molding according to one embodiment of the present invention.

FIG. 7 is a process chart showing a procedure of press molding according to an embodiment of the present invention.

FIG. 8 is a diagram for explaining an operation by a rough surface.

FIG. 9 is a side cross-sectional view according to one embodiment of the present invention for explaining a forming process by a forming die having a rough surface formed at a position corresponding to an outer side of the lens outer diameter after centering.

FIG. 10 is a side cross-sectional view according to an embodiment of the present invention for forming a biconvex lens having a flat portion in the periphery.

FIG. 11 is a cross-sectional view showing a relationship between a mold and glass for explaining a conventional problem.

[Explanation of symbols]

 G Glass preform 10 Mold 11 Upper mold 11a, 12a Mold surface 12 Lower mold 20 Rough surface 30 Flat part

Claims (16)

[Claims] 1. A molding die for molding a glass optical element by pressing a glass material softened on the molding surface, comprising an upper die and a lower die facing each other, wherein the upper die and the lower die are: Each of the molding surfaces has an optical function forming region for forming an optical function surface of the glass optical element, and a region other than the optical function forming region on the molding surface of the upper mold has a rough surface. And the maximum height of the irregularities represented by Rmax on the rough surface is larger than the maximum height of the irregularities represented by Rmax in a region other than the optical function forming region in the lower mold. A molding die for a glass optical element, comprising: 2. The rough surface has a maximum height Rmax of 0.1 μm.
The molding die for a glass optical element according to claim 1, which has the above rough surface. 3. The molding die for a glass optical element according to claim 1, wherein the upper mold has a molding surface including a plane perpendicular to the optical axis of the glass optical element to be molded. . 4. The molding die for a glass optical element according to claim 1, wherein the upper mold has a molding surface in which an optical function forming region is a convex surface. 5. The lower mold has a maximum height Rmax of 0.1 μm.
The molding die for a glass optical element according to claim 1, wherein the following rough surface is formed. 6. The lower mold has a maximum height Rmax of 0.03 μm.
4. A mirror surface having a diameter of not more than m.
Or a molding die for a glass optical element according to 4. 7. The method according to claim 1, wherein a rough surface of the molding surface of the upper mold and / or the lower mold is formed at a position of the molding surface corresponding to an outer peripheral portion of the glass to be removed. 7. The molding die for a glass optical element according to 2, 3, 4, 5, or 6. 8. A method for producing a glass optical element by press-molding a glass material with a molding die including an upper die and a lower die having opposing molding surfaces, wherein the optical element is formed on the molding surface of the upper die. Height Rmax larger than the maximum height Rmax of the area other than the optical function forming area on the molding surface of the lower mold in the area other than the functional function forming area
Performing the press molding with a molding die having a rough surface having the following, and transferring the rough surface to the glass material; cooling the molding die and the glass after the press molding; A step of relatively separating the upper mold and the lower mold, and a step of taking out the formed glass from a molding surface of the lower mold. 9. The method according to claim 8, wherein the upper mold has a rough surface having a maximum height of 0.2 μm or more. 10. The glass optical device according to claim 8, wherein a rough surface having a maximum height Rmax of 0.1 μm or less is formed in a region other than the optical function forming region of the lower mold forming surface. Device manufacturing method. 11. The glass optical element according to claim 8, wherein a region other than the optical function forming region of the molding surface of the lower mold is a mirror surface having a maximum height Rmax of 0.03 or less. Method. 12. The glass optical device according to claim 8, wherein the upper mold has a molding surface including a plane perpendicular to the optical axis of the glass optical element to be molded. Device manufacturing method. 13. The method according to claim 8, wherein the upper mold has a molding surface whose optical function forming region is convex.
13. The method for producing a glass optical element according to 10, 11, or 12. 14. The glass substrate according to claim 8, wherein said rough surface is formed at a position of said forming surface corresponding to an outer peripheral portion of said glass to be removed. A method for producing a glass optical element. 15. The step of relatively separating the molding surfaces of the upper mold and the lower mold, wherein the temperature of the glass after the pressing is lower than a temperature corresponding to a viscosity of 10 ¹² poise, and The method according to claim 8, wherein the heating is performed when the temperature is higher than −50 ° C.
15. The method for producing a glass optical element according to 12, 13, or 14. 16. The method according to claim 8, further comprising the step of removing the rough surface forming portion.
16. The method for producing a glass optical element according to 2, 13, 14 or 15.