JPH06115956A - Mold for optical glass molding, method for molding optical glass material using the same and optical glass material obtained by the method - Google Patents

Abstract

PURPOSE:To provide the subject inexpensive mold unnecessary for the precision processing for the whole molding face with shortened processing time, and also enabling glass feedstock to be molded to desired design and weight without the need for previously regulating such design and weight, thus leading to obtaining inexpensive optical glass materials. CONSTITUTION:Using a pair of top and bottom molds 9, 10 having the molding face provided adjacently with a glass material supporting face 1, glass material design controlling face 2 and space 3, a glass feedstock is held on the supporting face 1 followed by press molding, and the design of the free face of the glass material formed in the space 3 is controlled by the controlling face 2 and also an excess portion of the glass material is cut off by the supporting face 1, thus obtaining the objective optical glass material 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical glass molding die for forming high-precision optical glass elements such as lenses and prisms used in optical equipment and glass materials for molding by an ultra-precision glass molding method. The present invention relates to a method for forming an optical glass material and an optical glass material obtained thereby.

[0002]

2. Description of the Related Art In recent years, as a method of manufacturing a high-precision optical lens, particularly an aspherical glass lens, many attempts have been made to form it by one-shot molding without a polishing step, and it is being realized. As one of the forming methods, there is a method in which a supply glass material processed into a desired shape is heated to a deformable temperature, for example, a temperature near the softening point, and is formed using a means such as press forming ( For example, JP 61-21927 A).

FIG. 9 is a cross-sectional view showing a state in which an optical glass element is formed by molding a spherical supply glass material with a conventional optical glass molding die. Mold 2 inside the barrel 31
9, 30 are arranged so that their mold surfaces face each other,
The body glass 31 and the molding dies 29, 30 can hold the supplied glass material. Press heads 27 and 28 equipped with a heating and pressurizing mechanism are installed on the bases of the molding dies 29 and 30, respectively.

In the above structure, the weight and shape of the supplied glass material is adjusted to the molding dies 29, 30 and the body mold 3.
1 and is heated and pressed by the press heads 27 and 28. When the deformation is completed, the molds 29, 30,
The body mold 31 and the formed optical glass element 32 are gradually cooled, and after reaching a temperature at which the optical glass element 32 can be taken out, the molding die 29 is opened and the optical glass element 32 is taken out.

[0005]

However, in the molding method as described above, since the entire molding surface of the pressing mold comes into contact with the glass material, a molding die having a highly precise surface shape and structure is required. Therefore, not only when forming a desired optical glass element, but also when obtaining a feed glass material for molding, it is necessary to perform precision processing on the entire mold surface of the molding die, which requires a long processing time. It was a factor of cost increase.

Further, when the glass material and the molding die surface are fused to each other, it is necessary to rework the entire surface of the die surface, which requires a great deal of labor and cost. Further, since the supplied glass material comes into contact with the surface of the mold before pressurization, the surface of the mold at the contact portion may be deteriorated or the molded glass material at the contact portion may be adversely affected.

Further, when a flat glass material is molded with a molding surface having a concave surface, a gap portion which is not transfer-molded is generated between the molding surface and the surface of the glass material, and an optical glass element having a desired shape is obtained. Of course, a glass material for molding cannot be obtained. For this reason, in order to obtain a desired optical glass element with such a molding die, it is necessary to perform processing for adjusting the weight and shape of the supplied glass material in advance, and this is also very difficult for the supplied glass material and the molded optical glass element. It has a problem that it becomes expensive.

The present invention solves the above problems and uses an optical glass molding die which has a small area to be machined on the molding die surface and is capable of adjusting the shape and weight of the glass material to be supplied. It is an object of the present invention to provide an optical glass material molding method and an optical glass material obtained thereby.

[0009]

In order to solve the above problems, according to the present invention, a space portion, a glass material shape control surface and a glass material supporting surface are provided side by side on a molding die surface of an optical glass molding die.

Further, the present invention uses an optical glass molding die in which a space portion, a glass material shape control surface and a glass material supporting surface are provided side by side on at least one molding surface, and a glass material supporting surface holds a supply glass material. After that, pressure is applied with an optical glass molding die to mold the optical glass material by a method in which the shape of the glass material free surface formed in the space is controlled by the glass material shape control surface.

[0011]

[Operation] By forming the molding die surface with the space portion, the glass material shape control surface and the glass material supporting surface, it is not necessary to machine the entire molding die surface. The correction can be performed in a short time and with a small labor. Since the supplied glass material contacts only the glass material supporting surface and the surface shape is determined by the space, it does not adversely affect the molding die surface and the glass material surface. In addition, the shape control surface of the glass material can control the shape of the free surface formed in the space, and since the mold surface has the space, a molded product with no gap and good surface condition can be obtained. To be Furthermore, the glass material can be stably held on the glass material supporting surface, and stress is applied to the glass material by this supporting surface. It is possible to obtain a glass material.

[0012]

EXAMPLES An optical glass molding die, an optical glass material molding method, and an optical glass material according to embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a sectional view showing an optical glass molding die according to a first embodiment of the present invention, wherein (a) is an overall view and (b) is a portion A in (a). FIG. 2 is a sectional view showing a state in which the supply glass material is held by the optical glass molding die of FIG. 1, FIG. 3 is a sectional view showing a state after completion of the pressure molding, and FIG. 4 is obtained by molding. It is sectional drawing of the obtained optical glass material.

The optical glass molding die is formed in a cylindrical shape, and an opening 3a is formed in one side of the optical glass molding die, and a base portion 3b is formed in the other side. A glass material supporting surface 1 and a glass material shape control surface 2 are formed on the end surface on the side of the opening 3a, and a space 3 is provided inside, and the glass material supporting surface 1 can support the supply glass material 11. There is. The glass material supporting surface 1 is processed into an R curved surface, the glass material shape control surface 2 is processed into a conical shape, and the boundary surface between the glass material supporting surface 1 and the glass material shape control surface 2 is subjected to R surface processing. And has a smooth shape.

The optical glass molding die 9, 1 having such a structure
2 are arranged so as to face each other, and a flat glass feed glass material 11 is arranged and held therebetween. The supply glass material 11 is held so as to contact only the glass material supporting surface 1 of the molding dies 9 and 10.

Next, the supply glass material 11 and the molding die 9,
10 is heated by the press heads 7 and 8 equipped with a heating / pressurizing mechanism or some heating means (not shown). When the supply glass material 11 reaches a desired temperature, the supply glass material 11 is pressed by the molding dies 9 and 10 using the press heads 7 and 8. The supply glass material 11 gradually deforms due to natural deformation due to surface tension and the like and the pressurization of the molding dies 9 and 10. At this stage, the supply glass material 11 that has been in contact with only the glass material supporting surface 1 of the molding die surface until now gradually contacts the glass material shape control surface 2. Then, in the space portion 3 formed on the molding die surface, the supply glass material 11 forms a free-form surface without contacting the molding die surface.
The free-form surface formed by the space 3 is the area of the contact surface of the glass material shape control surface 2 with the supply glass material 11,
The desired shape can be controlled by the shape such as the angle.

When the pressing is completed, the optical glass material 12 has the shape shown in FIG. Then, the molds 9 and 10 and the optical glass material 12 are cooled. At this time, since the glass material shape control surface 2 has a conical shape and the boundary surface between the glass material support surface 1 and the glass material shape control surface 2 is R-shaped and has a smooth shape, it is formed in the cooling process. Concentration of stress is prevented. On the other hand, in the cooling process, the molds 9, 10
When the optical glass material 12 is pressed through the glass element supporting surface 1 of No. 2, the surplus portion of the glass material located outside the portion corresponding to the glass material supporting surface 1 is divided and cut by the concentrated stress.

As a result, the shape as shown in FIG. 4, that is, the free surface 15 obtained in the space 3, the press molding surface 14 obtained in the glass material shape control surface 2, and the glass material supporting surface 1 are formed.
The optical glass material 13 having the fractured surface 16 obtained in (1) is obtained. The excess portion of the optical glass material 13 is cleaved to have a desired weight. In this example, the surplus portion was divided and cut by the concentrated stress of pressurization, but it is divided by the contraction force of the glass material, or by applying a thermal stress by increasing the temperature difference between the glass material and the mold. Any of the following methods may be used.

(Embodiment 2) FIG. 5 is a sectional view showing an optical glass molding die according to a second embodiment of the present invention, wherein (a) is an overall view and (b) is a portion B in (a). FIG. 6 is a sectional view showing a state in which the supply glass material is held by the optical glass molding die of FIG. 5, FIG. 7 is a sectional view showing a state after completion of the pressure molding, and FIG. 8 is obtained by molding. It is sectional drawing of the obtained optical glass material.

The optical glass mold has the same structure as the optical glass mold shown in FIG. 1, except that the glass material supporting surface 4 is processed into a wedge shape and the glass material shape control surface 5 is a part of a spherical surface. And has a glass material supporting surface 4
The boundary surface between the glass material shape control surface 5 and the glass material shape control surface 5 is R-shaped and has a smooth shape.

The optical glass molding die 19 having such a structure,
As shown in FIGS. 6 and 7, 20 are arranged so as to face each other, and a biconvex supply glass material 21 is arranged and held therebetween. The glass material 21 to be supplied is formed by the molds 19 and 20.
It is held so as to contact only the glass material supporting surface 4.

Next, the supply glass material 21 and the molding die 1
9, 20, the press head 17 equipped with a heating and pressing mechanism,
18 or some heating means (not shown). When the supply glass material 21 reaches a desired temperature, the supply glass material 21 is pressed by the molding dies 19 and 20 using the press heads 17 and 18. The supply glass material 21 gradually deforms due to natural deformation due to surface tension and the like and the pressurization of the molding dies 19 and 20. At this stage, the supplied glass material 21, which has been in contact only with the glass material supporting surface 4 of the molding die surface so far, gradually contacts the glass material shape control surface 5. Then, in the portion of the space portion 6 formed on the molding die surface, the supply glass material 21 forms a free curved surface without contacting the molding die surface. The free-form surface formed by the space 6 is
The glass material shape control surface 5 can be controlled to have a desired shape by the area of the contact surface with the supply glass material 21 and the shape of the angle.

When the pressing is completed, the optical glass material 22 has the shape shown in FIG. Then, the molds 19 and 20 and the optical glass material 22 are cooled. At this time, in the cooling process, the press heads 17 and 18 and the molding dies 19 and 20 are rapidly cooled to a temperature lower than the temperature of the glass material 22 by some method (not shown) and the glass material supporting surface 4 of the molding die surface is used. By applying thermal stress, the surplus portion of the glass material located outside the portion corresponding to the glass material supporting surface 4 is divided and cut.

As a result, an optical glass material 23 having a shape as shown in FIG. 8, that is, a free surface 25 obtained in the space 6, a press molding surface 24, and a split surface 26 is obtained. The obtained optical glass material 23 can be used not only as a supply glass material for molding an optical glass element, but also as an optical glass element as long as the accuracy of the optical glass element is satisfied.

[0025]

EFFECTS OF THE INVENTION According to the present invention, it is sufficient to process a very small area between the glass material shape control surface and the glass material supporting surface without performing precision processing on the entire surface of the molding die. It is possible to shorten and shorten the correction time. In addition, the shape control surface of the glass material makes it possible to control the shape of the free surface formed in the space. In addition, since the mold surface has a space, it has a good surface with no surface defects such as gaps. An optical glass material is obtained. Furthermore, it is possible to obtain an optical glass material that is in a state of being limited to a desired weight by using a supply glass material that is not weight-limited, so that the glass material processing cost and the price of the molded optical glass material and element Is greatly reduced.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an optical glass molding die according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a state of an optical glass molding die and a supply glass material immediately before pressure molding in which a supply glass material is held by the optical glass molding die of FIG.

FIG. 3 is a cross-sectional view showing a state of the optical glass molding die and the supply glass material when the pressure molding of the supply glass material is completed by the optical glass molding die of FIG.

4 is a cross-sectional view of an optical glass material obtained by the optical glass molding die of FIG.

FIG. 5 is a cross-sectional view of an optical glass molding die according to another embodiment of the present invention.

6 is a cross-sectional view showing a state of an optical glass molding die and a supply glass material immediately before pressure molding in which a supply glass material is held by the optical glass molding die of FIG.

7 is a cross-sectional view showing a state of the optical glass molding die and the supply glass material when the pressure molding of the supply glass material is completed with the optical glass molding die of FIG.

8 is a cross-sectional view of an optical glass material obtained with the optical glass molding die of FIG.

FIG. 9 is a cross-sectional view showing a state of a conventional optical glass molding die and an optical glass element when heating and pressing are completed.

[Explanation of symbols]

 1 glass material support surface 2 glass material shape control surface 3 space part 4 glass material support surface 5 glass material shape control surface 6 space part

Claims (10)

[Claims] 1. An optical glass molding die for press-molding a supply glass material, characterized in that a space portion, a glass material shape control surface and a glass material supporting surface are provided side by side on a molding die surface. Type. 2. At least one of the boundary between the space and the glass material shape control surface, the boundary between the glass material shape control surface and the glass material support surface, or at least one of the outermost circumferences of the glass material support surface is curved. The optical glass molding die according to claim 1, wherein 3. The optical glass molding die according to claim 1, wherein at least a part of the sectional shape of the glass material supporting surface is a curved surface or a wedge shape. 4. The optical glass molding die according to claim 1, wherein the shape of the glass material shape control surface is a part of any one of a spherical surface, a conical surface, and an aspherical surface. . 5. An optical glass molding die in which a space portion, a glass material shape control surface and a glass material supporting surface are provided side by side on at least one molding die surface, and the glass material supporting surface holds the supplied glass material, and then the above-mentioned method is used. Press with an optical glass mold,
An optical glass material molding method, characterized in that the shape of the glass material free surface formed in the space is controlled by a glass material shape control surface. 6. The supply glass is pressed through the glass material supporting surface of the optical glass molding die by pressurizing the supply glass material with the optical glass molding die or by providing a temperature difference between the optical glass molding die and the supply glass material. The optical glass material molding method according to claim 5, wherein the material is subjected to concentrated stress and / or thermal stress. 7. An optical glass material, which is formed by heating a supply glass material and pressing it with an optical glass molding die, and has a free surface, a pressing surface and a split surface. 8. The shape of the press-molding surface is a part of a spherical surface, a conical surface, or an aspherical surface.
Optical glass material described. 9. The optical glass material according to claim 7, wherein the boundary surface between the free surface and the press molding surface is a curved surface. 10. An optical glass molding die in which a space, a glass material shape control surface and a glass material supporting surface are provided side by side on at least one molding die surface, and the glass material supporting surface holds the supplied glass material, The optical glass material according to claim 7, wherein the optical glass material is obtained by pressurizing with an optical glass mold and controlling the shape of the glass material free surface formed in the space by the glass material shape control surface.