JPH04285020A - Device for forming optical element - Google Patents

Abstract

PURPOSE:To form plural kinds of optical elements of different shapes with the glass material and carrier disk of the same shape. CONSTITUTION:A glass material 1 placed on a carrier dish 2 by a carrier arm 3 is heated in a heating furnace 17, softened and introduced between the upper and lower dies 15 and 9. A large step is made by the adjustment of a spacer 12 when a thin optical element is formed, and, conversely, a small step is made by the adjustment of the spacer 12 when a thick optical element is formed.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention allows grinding and
Regarding a molding device that can manufacture glass optical elements with high surface precision and surface roughness without the need for a polishing process, more specifically, it can mold multiple optical elements with different shapes using a single-shaped glass material. Regarding possible devices.

0002

2. Description of the Related Art In recent years, a method for manufacturing glass optical elements such as aspherical lenses by press molding has been developed and is attracting attention.

Conventionally, the following inventions have been disclosed as apparatuses for molding optical elements by reducing variations in wall thickness.

For example, in the invention described in Japanese Patent Laid-Open No. 59-141435, an apparatus has been proposed in which a part of the outer circumference regulating member is provided with a cavity through which the remaining portion of the glass escapes.

[0005] Furthermore, in the invention described in Japanese Patent Publication No. 63-10100, a pair of periphery regulating members that are slidably fitted to the outer periphery of the mold are provided, and the gap formed between the periphery regulating members is filled with excess glass. Devices have been proposed to drain the amount.

[0006]

SUMMARY OF THE INVENTION The inventions in the above-mentioned prior art are aimed at solving the drawbacks in which variations in the weight of glass materials before molding directly result in variations in optical elements.

In recent years, there has been a strong demand for improved productivity, and when molding optical elements of the same type of glass, although their shapes are slightly different, it is effective to mold them using glass materials of the same shape.

[0008] The above molding was carried out in accordance with the above-mentioned Japanese Patent Application Laid-open No. 59-141435.
If the apparatus described in the publication is used, the size of the gap provided in the mold member for regulating the outer periphery must be individually changed depending on the shape of the optical element. However, the mold member is made of a material with a coefficient of linear expansion smaller than that of the glass material (
For example, ceramics, cermets, etc.) must be used, and these materials are generally difficult to process, resulting in high costs. Furthermore, taking out the optical element requires sufficient cooling, resulting in low productivity.

[0009] Also, the above molding was carried out in the above-mentioned Japanese Patent Publication No.
If the apparatus described in the 00 publication is used, it is possible to greatly change the thickness of the optical element by changing the amount of gap between the peripheral regulating members in accordance with the shape of the optical element. However, taking out the optical element requires sufficient cooling, resulting in low productivity.

[0010] Therefore, the present invention was developed in view of the drawbacks of the prior art, and uses a glass material of a single shape to efficiently manufacture multiple types of optical elements having different shapes (particularly wall thicknesses). The object of the present invention is to provide an optical element molding device that can be mass-produced.

[0011]

[Means for Solving the Problems] The present invention provides a conveying member whose inner diameter changes in the axial direction and supports the material of an optical element at the inner diameter portion, and a molding surface whose position changes in the axial direction during molding of the optical element. A plurality of different sets of molds are provided, and a desired mold is selected from the plurality of sets of molds to perform molding, thereby obtaining a plurality of types of optical elements.

[0012] Furthermore, the above-mentioned conveying member has stepped portions having different inner diameters arranged in parallel in the axial direction.

Furthermore, the conveying member is formed into a mortar shape with an inner diameter inclined in the axial direction.

[0014]

[Operation] In the present invention, when press-forming a thin optical element, the positioning member is positioned relative to the mold so that the outer periphery of the glass material can be regulated by the larger-diameter portion of the inner surface of the conveying plate. (or a mold may be manufactured to take this position). This increases the amount of outflow in the radial direction of the glass material, making it possible to mold a thin optical element.

On the other hand, when press-molding a thick optical element, the positioning member relative to the mold is adjusted so that the outer periphery of the glass material can be regulated by the smaller diameter part of the inner surface of the conveying plate. Set the position. Thereby, the amount of outflow in the radial direction of the glass material is suppressed, and a thick optical element can be molded.

[0016]

Embodiments Hereinafter, embodiments of the optical element molding apparatus according to the present invention will be described in detail with reference to the drawings.

[0017]

Embodiment 1 FIGS. 1 to 5 show this embodiment, with FIG. 1 being a schematic configuration diagram, FIGS. 2 to 5 being sectional views, and FIGS. 6 to 9 being sectional views showing modified examples.

Reference numeral 1 is a cylindrical glass material whose both end faces are polished to a mirror finish. A transport tray 2 for storing and transporting the glass material 1 is placed at the tip of a transport arm 3. Two stepped portions 4 and 5 are formed on the inner surface of the conveying tray 2, and from the bottom, an inner surface portion 6 with a smaller diameter than the outer diameter of the glass material 1 and a first step portion with a larger diameter than the outer diameter of the glass material 1 are formed. an inner surface 7 and a second inner surface 8 having a larger diameter than the first inner surface 7.
and are formed sequentially.

Reference numeral 9 denotes a lower mold having a molding surface 10 having a shape corresponding to the functional aspect of the optical element on the upper end surface.
A positioning member 11 for positioning the transport tray 2 is inserted into the frame. The positioning member 11 is screwed to the lower mold 9 with a fixing screw 13 with a spacer 12 interposed so that the step A between the upper end surface and the molding surface 10 of the lower mold 9 can be adjusted. .

Above the lower mold 9, a molding surface 14 is formed on the lower end surface.
An upper mold 15 that forms a pair with the lower mold 9 is disposed to face the lower mold 9. A positioning member 16 is fitted onto the upper mold 15 in the same way as the lower mold.

A heating furnace 17 for heating and softening the glass material 1 to a predetermined temperature is installed near the upper and lower molds 9 and 15.

[0022] In the molding apparatus having the above configuration, the glass material 1 placed on the transport tray 2 by the transport arm 3 is heated and softened in the heating furnace 17, and then transported between the upper and lower molds 9 and 15 to be molded. conduct.

When molding a thin optical element 18, FIG.
As shown in the figure, a large step B is created by adjusting the spacer 12. Thereby, the outer circumference of the glass material 1 is regulated by the second inner circumferential surface 8. As a result, the amount of glass material 1 flowing out in the radial direction increases, and the optical element 18 becomes thinner.

On the other hand, when molding a thick optical element 18, a small step C is created by adjusting the spacer 12, as shown in FIG. As a result, most of the outer periphery of the glass material 1 is regulated by the first inner surface 7 and the small-diameter inner surface 6, and the optical element 18 becomes thick.

When molding the optical element 18 between the thin optical element 18 and the thick optical element 18, as shown in FIG. Adjust and perform molding.

At this time, the step of the positioning member 16 with respect to the upper mold 15 is determined between each positioning member 11, 16 and the upper and lower end surfaces of the conveying plate 2 when the optical element 18 is molded to a desired thickness. Set so that there are no gaps.

[0027] In order to easily take out the optical element 18 after molding from the transport tray 2, it is common practice to use a material with a coefficient of thermal expansion smaller than that of the glass material 1 for the material of the transport tray 2. There is. Therefore, during molding, the amount of shrinkage in the vertical direction of the glass material 1 becomes larger than the amount of shrinkage of the transport tray 2, and as a result, the pressure applied by the upper and lower molding dies 9, 15 is applied to the transport tray 2.
, and no load is applied to the glass material 1 in some cases. In this state, the glass material 1 shrinks non-uniformly, and it may not be possible to obtain an optical element 18 with high shape accuracy. In such a case, the spacer 12 interposed between the mold 9 and the positioning member 11 is made of an elastic material. This allows the upper and lower molds 9 and 15 to keep pressing the glass material 1 during molding, making it possible to obtain an optical element 18 with high shape accuracy.

According to this embodiment, it is only necessary to form two stepped portions 4 and 5 on the inner surface of the conveying plate 2, and processing can be simplified. Also, the height of the positioning member 11 can be adjusted using the spacer 12.
All you have to do is replace it, which is a simple task. Furthermore, by transferring the glass material 1 between the upper and lower molds 9 and 15 using the conveyor tray 2, heating of the glass material 1 and cooling after molding can be done as separate processes, making it possible to efficiently use a single mold. Can be mass produced.

The present invention is not limited to the cylindrical glass material 1, but a spherical glass material 19 can also be used as shown in FIG.

Furthermore, the present invention does not limit the number of steps of the conveying tray 2 to two, but as shown in FIGS. 7 to 9, the number of steps is three.
It is also possible to use a conveyor tray 20 formed in two ways.

[0031]

Embodiment 2 FIGS. 10 and 11 are cross-sectional views showing this embodiment.

In this embodiment, a stepped portion 21 is formed at the lower part of the inner surface in place of the conveying tray 2 in the first embodiment, and
The difference is that the step part 21 is configured with a transport tray 23 having a mortar-shaped tapered surface 22 that is inclined in the axial direction and opened upward, and the other components are the same. The same numbers are given to the constituent parts, and the explanation of the structure will be omitted.

When molding a thick optical element 18, the molding apparatus constructed as described above performs molding with a small step E between the lower mold 9 and the positioning member 11, as shown in FIG. . Further, when molding a thin optical element 18, molding is performed with a large step F between the lower mold 9 and the positioning member 11, as shown in FIG.

Even when molding a thick or thin optical element 18, the outer periphery of the glass material should be aligned with the tapered surface 2 of the conveying plate 23.
It is regulated by 2. Therefore, the glass material can be molded under sufficient internal pressure.

According to this embodiment, since the inner surface of the conveying tray 23 is made into a tapered surface 22, uneven internal pressure is not applied to the glass material from the side during molding, and the glass shrinks uniformly. The shape accuracy of the optical element 18 is improved. Also,
The optical element 18 can be easily taken out from the transport tray 23 after molding.

Incidentally, as in the first embodiment, a spherical glass material 19 can also be used as shown in FIG.

[0037]

Embodiment 3 FIG. 13 is a sectional view showing this embodiment.

This embodiment differs from the first embodiment in that the upper and lower molds 9 and 15 and the positioning members 11 and 16 are integrated into upper and lower molds 31 and 32, and the other configurations are different. They consist of the same constituent parts, and the same constituent parts are given the same numbers and their explanations will be omitted.

A molding surface 33 is formed on the upper end surface of the lower mold 31. A step G is provided on the outer periphery of the molding surface 33, and a positioning portion 34 is formed.

[0040] The mold of the molding apparatus having the above configuration is as follows:
Although the optical element 18 must be manufactured separately in accordance with the desired shape, the step G is integrally processed so that the thickness of the optical element 18 conforms to the standard value.

According to this embodiment, the number of parts can be reduced and manufacturing costs can be reduced.

[0042]

Embodiment 4 FIG. 14 is a sectional view showing this embodiment.

[0043] This embodiment has the advantage that abutment surfaces are provided on a part of the conveying tray 2 and the positioning part 34 of the lower mold 31 in the third embodiment to ensure that their respective central axes coincide. The other components are the same, and the same components are designated by the same numbers and their explanations will be omitted.

Reference numeral 41 denotes a transfer plate, and a hole consisting of a flat portion 42 and a cylindrical portion 43 is bored in the inner surface of the lower end of the transfer plate 41 . In the positioning part 45 of the mold 44, a plane reference part 46 for preventing the transfer plate 41 from tilting and a cylindrical reference part 47 for preventing lateral displacement are arranged so as to correspond to the plane part 42 and the cylindrical part 43 of the transfer plate 41. is formed. The plane reference part 46 is formed perpendicular to the central axis of the mold 44, and the cylindrical reference part 47 is formed coaxially with the central axis. Further, the clearance between the cylindrical reference portion 47 and the cylindrical portion 43 of the transfer plate 41 is formed to be 10 μm or less.

[0045] During molding using the molding apparatus having the above configuration,
The flat portion 42 and the cylindrical portion 43 are engaged with the positioning portion 45, and the central axis of the conveyance plate 41 coincides with the central axis of the mold 44.

According to this embodiment, the molded optical element 1
8, the central axis and the central axis of the outer circumferential surface coincide with each other, so that the post-processing process for centering can be omitted.

[0047]

As explained above, according to the optical element molding apparatus according to the present invention, when molding optical elements having a plurality of different shapes made of the same glass material, it is possible to mold a single glass material and a single glass material. A plurality of types of optical elements having different shapes can be molded using a single-shaped transfer plate. Therefore, optical elements can be mass-produced at low cost compared to the conventional method in which molds and the like are individually created according to the shape of the optical element.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of Example 1.

FIG. 2 is a sectional view of Example 1.

FIG. 3 is a cross-sectional view of Example 1.

FIG. 4 is a cross-sectional view of Example 1.

FIG. 5 is a cross-sectional view of Example 1.

FIG. 6 is a sectional view showing a modification of the first embodiment.

FIG. 7 is a sectional view showing a modification of the first embodiment.

FIG. 8 is a sectional view showing a modification of the first embodiment.

FIG. 9 is a sectional view showing a modification of the first embodiment.

FIG. 10 is a cross-sectional view of Example 2.

FIG. 11 is a cross-sectional view of Example 2.

FIG. 12 is a sectional view showing a modification of the second embodiment.

FIG. 13 is a cross-sectional view of Example 3.

FIG. 14 is a cross-sectional view of Example 4.

[Explanation of symbols]

1 Glass material 2 Transport plate 3 Transfer arm 4 Stepped section 5 Stepped section 6 Inner surface part 7 Inner surface part 8 Inner surface 9 Lower mold 10 Molding surface 11 Positioning member 12 Spacer 14 Molding surface 15 Upper mold 16 Positioning member 17 Heating furnace 18 Optical element 19 Glass material 20 Transport plate 21 Stepped section 22 Tapered surface 23 Transport plate 31 Lower mold 32 Upper mold 33 Molding surface 34 Positioning member 41 Transport plate 42 Plane part 43 Cylindrical part 44 Molding mold 45 Positioning section

Claims (3)

[Claims] 1. A conveyance member whose inner diameter changes in the axial direction and supports a material for an optical element at the inner diameter portion, and a plurality of sets of molds each having a molding surface at a different position in the axial direction when molding the optical element. An apparatus for molding an optical element, characterized in that a plurality of types of optical elements are obtained by selecting a desired mold from among the plurality of sets of molds and performing molding. 2. The optical element molding apparatus according to claim 1, wherein the conveying member has stepped portions having different inner diameters arranged in parallel in the axial direction. 3. The optical element molding apparatus according to claim 1, wherein the conveying member is formed into a mortar shape with an inner diameter inclined in the axial direction.