JPH01148717A - Forming device of optical element - Google Patents

Abstract

PURPOSE:To produce optical elements having no surface defect and high dimensional precision with high efficiency by disposing a pair of die facing oppositely to each other so as to interpose fluid glass, press-forming the fluid glass, and separating a formed part from other parts by cutting with a hot cutting member. CONSTITUTION:A pair of die 5, 6 is disposed confrontingly so as to interpose fluid glass 2 falling down from a nozzle 1 of a melting furnace. Said fluid glass 2 is pressed in the die 5, 6 to obtain a formed part 21 having surfaces transferred from forming surfaces 5a, 6a. After cutting the fluid glass with a cutting edge 4, the formed part 21 is separated from other parts by cutting with a cutting ring heated at a desired temp. by a heater contained therein. Thus, an optical member is produced. By this constitution, a satisfactory cutting surface, namely, a side external peripheral surface of a formed product is formed because the fluid glass is cut by controlling the heating of the cutting ring 7.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to an apparatus for molding optical elements by press molding, and more specifically, the present invention relates to an apparatus for molding optical elements by press molding, and more specifically, the present invention relates to a molding device for optical elements by press molding, and more specifically, it is possible to improve surface accuracy without going through processes such as grinding and polishing after press molding. [1] Concerning a molding apparatus for a highly accurate optical element or a preform suitable for reheat pressing thereof.

(Prior art) In recent years, a method of molding high-precision optical elements that eliminates the need for post-processing such as grinding and polishing has been developed by housing a glass material in a mold with a predetermined surface accuracy and press-molding it. is being developed.

This press molding method generally includes a reheat press method and a direct press method.

In the reheat press method, the necessary amount of glass material that has been melted and solidified in advance is cut, the weight is adjusted using methods such as sanding, and the resulting glass pellets are placed in a mold for molding. This is a method of molding an optical element by heating the molds simultaneously or separately to a pressing temperature, and then pressing and transferring the optical functional surface formed on the mold by press molding.

On the other hand, in the direct press method, the necessary amount of molten glass flowing out or extruded from a molten glass outflow orifice is cut by a cutting blade, and the cut is directly dropped into a mold or charged into a chute, and then molded. This is a method of molding an optical element by pressing a mold.

In addition, in the above-mentioned reheat press method, the molten glass is put into a mold and press-molded, as in the direct press method described in L, without going through low-productivity steps such as cutting and sanding, and the final product is produced. After obtaining a pre-W4 molded product (preform) with a shape similar to that of the final product, the preform is placed in a mold having an optical functional surface with a precision equal to or higher than the shape and surface precision of the final product. There is a method of press molding.

(Problems to be Solved by the Invention) Optical elements obtained by these molding methods are required to have predetermined surface accuracy and dimensional accuracy in order to obtain good image forming quality, and for this reason, neither of the above methods Also, the weight of the glass material supplied to press molding to obtain the final product must be sufficiently adjusted.

However, in the above-mentioned method of press molding using small glass lumps, the weight of the small glass lumps is adjusted by cutting, sanding, etc., so that grains may remain on the surface of the molded product.
When heating a small glass lump before press molding, the mold release agent applied to prevent the glass and the heating tray from fusing together bites into the surface of the molded product during pressing, significantly deteriorating the surface precision of the molded product. There is a problem with doing so.

In addition, in the method of directly press-forming using molten glass, there is a problem that cutting marks called shear marks occur on the molded product when cutting with a cutting blade, and the surface precision of the molded product deteriorates. In this press molding method, the weight of the molded product is adjusted by cutting the molten glass flow.
There is also the problem that weight fluctuations occur in the molded product due to temperature changes in the molten glass flow, cutting timing, pulsation of the glass flow, etc., and predetermined dimensional accuracy cannot be obtained.

In addition, as a press molding method that particularly prevents the occurrence of shear marks, Japanese Patent Publication No. 41-9190 or Japanese Patent Application Laid-open No. 6
There is one described in Publication No. 1-132523.

In the molding method described in Japanese Patent Publication No. 41-9190, press molding is performed by pressing a mold in a direction perpendicular to the direction of flow of molten glass to fill the mold cavity with molten glass. When the mold is compressed, a phenomenon occurs in which excess glass in the mold cavity flows out from between the mold and the anvil facing it. As the pressing operation of the mold progresses, this excess glass increases its outflow resistance and is cooled by the mold, increasing its viscosity, until it is completely cut off between the mold and the opposing anvil. The molded product is cooled without being completely wet, and a protruding portion is formed on the outer periphery of the molded product. Therefore, after press forming, it is necessary to break the protruding portion and finish the broken surface. Furthermore, due to variations in the size of the molten glass flow, the thickness of the glass between the above-mentioned molded product and the protruding portion changes, causing variations in the thickness of the molded product, making it difficult to perform weight adjustment with high precision. There is also the problem of not having one.

On the other hand, in the molding method described in JP-A No. 61-132523, the accuracy of the molded product depends on the size of the flowing glass body before punching it, and highly accurate dimensions and shapes can be produced. A rod or glass sheet is required.

In order to solve the above-mentioned problems, the present inventors have already proposed a method for manufacturing an optical element in which the molded product is free from surface defects such as shear marks and has excellent dimensional and weight accuracy.

The present invention relates to this manufacturing method, in which the outer periphery of a part to be molded formed by a pair of molds is cut and separated using a cutting member, and when forming the outer periphery shape of a molded product, the cut surface is made to have good properties. An object of the present invention is to provide a molding device that can suppress the occurrence of distortion, sink marks, etc.

(Means for Solving the Problems) In order to achieve the above-mentioned object, the optical element molding apparatus of the present invention is arranged opposite to each other so as to narrow the glass fluid, and presses the glass fluid to form a molded part. The present invention is characterized by comprising a pair of molds, a cutting member provided on the outer periphery of the mold for cutting and separating the part to be molded from other parts, and means for heating the cutting member.

(Function) In the optical element molding apparatus configured as described above, each mold member constituting the pair of molds used is
and a second mold member, the respective molding surfaces of these mold members are arranged so as to face each other via the glass fluid. When the glass fluid is, for example, molten glass flowing out from a melting furnace through a nozzle, the arrangement of such molding molds is such that the first mold member and The molding surfaces of the second mold member can be arranged to face each other. In addition, in the case where the glass fluid is in the form of a rod or sheet that has fluidity by reheating an already molded product, in addition to the arrangement described above, the first mold member and the second mold member may each be It is also possible to arrange the labels to face each other in the vertical direction.

Therefore, for example, when a mold according to the present invention is constructed for a flowing molten glass fluid, each mold member is pressed against each other from a direction substantially perpendicular to the direction of flow of the glass fluid, and the mold members are pressed against each other from a direction substantially perpendicular to the direction of flow of the glass fluid. By adjusting the timing of suppression of each mold member with respect to the glass fluid,
The molded part can be formed while avoiding the tip of the glass fluid, that is, the cutting trace.

The wall thickness of the part to be formed is determined by setting the cavity of the shaping die. This cavity can be set by the distance between the molding surfaces when the mold members are closest to each other during press molding. Excess glass generated when pressing the 5 members flows freely outside the molding surface, and the thickness of the molded product is determined by the cavity of the mold without being affected by the size of the glass flow.

After pressing the glass fluid with each mold member to form a molded part, the molded part and other excess glass are cut and separated using a cutting member provided on the outer periphery of the mold, and the outer periphery of the molded part is cut and separated. A shape is formed.

The molded product thus obtained is formed from a part that does not contain cut marks of the glass fluid, so there are no surface defects such as shear marks, and the part to be molded by the set cavity and cutting member is not damaged. By forming the outer periphery, a molded product with high shape accuracy and weight accuracy can be obtained. In addition, since the functional surface of this molded product is formed by transferring the molding surface of each mold member, the surface texture of each molding surface can be made with high precision equal to or higher than that of the desired molded product. By finishing the product and press-molding it, a molded product with a high-precision surface can be obtained.

Furthermore, the present invention □ includes means for heating the cutting member. This heating means can be achieved by, for example, comprising a temperature control means that changes the temperature of the mold according to the molding process, and a temperature control means that controls the temperature of the cutting member according to the temperature of the mold. be done. By using such heating means, the cut surface of the part to be molded is finished in good condition, and the entire part to be molded is evenly cooled, so that a molded product with little distortion can be obtained.

In addition, the viscosity of the glass fluid in the present invention is lO~107
Boaz is preferred. When the glass viscosity is lower than 1O poise, the glass flow becomes filamentous and the required glass capacity within the mold cavity becomes insufficient.
When the glass viscosity is higher than lOl poise, it becomes difficult to cut the glass after press molding. Note that the optimum viscosity of these glass fluids is 103 to 105 poise.

Another example of the softened glass fluid in the present invention is:

As mentioned above, in addition to molten glass, glass fluids obtained by reheating preformed glass ronds or sheets may also be used.The optimum viscosity of these glass fluids is 103 to 105 poise. .

Furthermore, the temperature of the molding die ranges from a temperature corresponding to 108 poise in terms of glass viscosity to the glass transition point (hereinafter referred to as T).

It is called. Corresponds to approximately IQ+3 in terms of glass viscosity. ) It is necessary to set the temperature within the range of 100"C lower (Tg - 100℃) than The hardness of the glass surface in the molding part changes slowly, making it impossible to obtain the desired shape accuracy and surface accuracy when cutting and forming the outer periphery of the molded part.Furthermore, the glass and the molding surface of the mold tend to fuse together. On the other hand, if the mold temperature is Tg
If the temperature is lower than -100° C., cutting the outer periphery of the molded part becomes difficult, and there is a risk that cracks may occur from the cut portion.

The viscosity at the time of taking out the molded product is approximately 10% when the molded product is used as a preform for reheat press.
It is sufficient to cool it until the viscosity reaches Poise or higher, but
When used as is for optical lenses, etc., it can be used as an optical element with good shape accuracy and surface accuracy by cooling it in a mold while applying pressure and taking it out when the viscosity reaches about 1Q14.5 poise. be able to.

Note that in order to maintain the lifespan of the mold and the cutting member, it is desirable that the press molding and subsequent cutting treatment in the present invention be performed in a non-oxidizing atmosphere.

(Example) Examples of the present invention will be described below with reference to the drawings.

FIG. 1(a) is a schematic sectional view of a press forming apparatus used in an embodiment of the present invention, and FIG. 1(b) is a schematic sectional view of a press forming apparatus used in an embodiment of the present invention.
FIG. 2 is an enlarged cross-sectional view of a main part of the press molding apparatus shown in FIG.

In FIG. 1(a), 1 is a nozzle through which molten glass flows out from a melting furnace (not shown), 2 is a glass fluid flowing out from this nozzle, and 3 is a cut mark produced at the tip of the glass fluid 2. be. Reference numeral 4 denotes a cutting blade that is provided below the nozzle l and cuts the glass fluid 2 by opening and closing operations by a drive device (not shown). This cutting blade 4 operates and cuts the glass fluid 2 midway, resulting in a cut mark 3.
occurs.

The press molding apparatus shown in this embodiment is configured to allow the glass fluid 2 to flow down from the nozzle 1.
A first mold member 5 and a second mold member 6 constituting a pair of molding molds are arranged so as to face each other so as to sandwich the glass fluid 2 from substantially perpendicular directions. Each mold member 5.6 is
Molding surfaces 5a and 6 whose opposing surfaces are mirror-finished
It has a.

The first mold member 5 is held by a slider 14, and this slider 14 is supported by a sliding rotation portion of a slide shaft 18. 16 is a cylinder that drives the slider 14, and the operation of this cylinder 16 causes the slider 1 to move.
4 moves in the sliding direction of the slide shaft 18 to press the first mold member 5.

On the other hand, the second mold member 6 is connected to a cylinder 13 via an adapter 12, and the operation of the cylinder 13 causes the second mold member 6 to be suppressed.

The cavity formed by each molding surface 5a, 6a of these mold parts 5.6 can be defined by the stroke of each cylinder 13.16.

Further, a cutting ring 7 having a cutting blade formed on the first molding member 5 side is provided on the outer periphery of the second molding member 6, and this cutting ring 7 is slidably supported by the slide shaft 18. The slider 15 is connected to the slider 15. Further, the slider 15 is connected to a cylinder 17, and this cylinder 1
7 allows the cutting ring 7 to slide around the outer periphery of the second mold part 6 in a movement independent of the second mold part 6.

Also, 19 is the base of the entire device, and the cylinder 13
．． 16, 17 and the slide shaft 18 are firmly supported.

Furthermore, as shown in FIG. 1(b), the first mold member 5 and the second mold member 6 have built-in heaters 30 and 31 for heating, each having a built-in thermocouple for measuring mold temperature. There is. 32.
33 is a conducting wire connected to each heater. Furthermore, heaters 34, 35 and a thermocouple 39 are built into the cutting ring 7. 36, 37, and 38 are conductive wires connected to each heater and thermocouple. These conductive wires are connected to a controller 40 installed outside the molding apparatus. This controller is equipped with a power regulator 41, a temperature regulator 42, and an external power source 43 for the power regulator 41.

The 8-electrocouple 36 is connected to the temperature controller 42 and outputs the measured value detected by the thermocouple 36 to the power controller 41 as an output control signal.
The heater 34.3 is controlled by the power regulator.
5 heats the cutting ring 7.

The illustrated controller described above is connected to the cutting ring 7, but a similar controller (not shown) is also connected to the mold member 5.6.

These controllers control the mold member 5,
6, and the temperature of the cutting ring 7 is controlled depending on the temperature of the mold member 5.6.

Next, the operation of this apparatus will be explained using FIGS. 2 to 7 and FIG. 8.

2 to 7 are main part sectional views showing the operating state of this device in each step J order, and FIG. 6. It is a timing chart showing the operation timing of each part of the cutting blade 4 and the cutting ring 7, and the horizontal axis shows time T. The operation timing of these operating parts is controlled by a controller (not shown) connected to each operating part. be able to.

FIG. 2 shows the state immediately before press molding, with glass fluid 2 flowing down from nozzle 1. At the point when the tip of the glass fluid 2, that is, the cutting mark 3 flows downward from each opposing molding surface 5a, 6a, the first mold member 5 and the second mold member 6
starts suppressing operation. In FIG. 8, T=0 indicates the timing at which both mold members 5 and 6 start operating.
6 may be started at the same time on both sides, but it is preferable that the end time T2 of the pressing operation of the mold members 5 and 6 against the glass fluid 2 is at the same time on both sides or within an error of at most ±0.05S. If it is too large, only one of the mold members 5 and 6 collides with the glass fluid 2, causing undesirable lateral play in the glass fluid 2. After that, the mold members 5 and 6 collide with the glass fluid 2, which is undesirable.
As shown in the figure, the state in which the glass fluid 2 is pressed against the molded part 21 is maintained for a predetermined period of time, and during this time, pressure transfer is performed on both surfaces of the molded part 21 by the respective molding surfaces 5a and 6a. .

The operation start time and the cutting start time of the cutting blade 4 may be the same as the operation start time T=O of the mold members 5 and 6, respectively.
The cutting blade 4 must finish cutting the glass fluid 2 at the same time as the mold members 5 and 6 hold the glass fluid 2, or at least after the mold members 5 and 6 hold the glass fluid 2. It won't happen.

Thereafter, the cutting blade 4 is returned to its original state. 8th
In the figure, the return start time of the cutting blade 4 is shown as T4, and the return end time is shown as T5. Preferably, the time required from the operation start time T=0 of the cutting blade 4 to the cutting end time T2 is set to 0.3 to 0.45.

As shown in FIG. 5, the operation start timing T1 of the cutting ring 7 is such that the cutting blade 4 finishes cutting the glass fluid 2 (T2) at least before the cutting ring 7 finishes cutting the outer periphery of the molded part 21 (T3). By doing so, when the cutting operation of the cutting ring 7 is completed, the glass fluid 2 is already cut off by the cutting blade 4, and the glass fluid 2 is cut off by the cutting ring 7. The cut piece 22 can be easily moved to the outside of the first mold member 5. Thus, the cutting ring 7 is connected to the second mold member 6
The outer periphery of the molded part 21 is cut while sliding along the outer periphery of the molded part 21, thereby forming the outer peripheral shape of the molded part 21.

Thereafter, the cutting ring 7 maintains the state at the end of cutting (T3), cools the molded part 21 from the outer periphery due to the temperature difference while holding the outer periphery of the molded part 21, and cools the molded part 21 from the outer periphery near the outer periphery of the molded part 21. increases in viscosity and its shape changes. On the other hand, after being pressed by the mold members 5 and 6, the molded part 21 is cooled from both surfaces due to the temperature difference between the mold members and the molded part 21, increasing its viscosity and stabilizing its surface shape.

Next, as shown in FIG. 6, the first mold member 5 is returned to its original state. Assuming that the operation start time is T6, the operation end time is T, and the start time for returning the cutting ring 7 to its original state is at the same time as or after the return end time T7 of the first mold member 5, cutting Before the operation of the ring 7 starts, the part to be formed 21 is held by the bending J-cutting ring 7, and does not fall down naturally.

Then, at the same time as the return completion time T8 of the cutting ring 7, the part to be molded, that is, the molded product 23 is taken out. This can be done using a known suction hand or the like. After this removal operation is completed, the second mold member 6 is returned to its original state. In FIG. 8, the return start time of the second mold member 6 is shown as T9, and the return end time is shown as TIO.

Note that although FIG. 7 shows the state in which the cutting ring 7 has been returned, the molded product 23 is released from the holding of the cutting ring 7 and falls naturally.

In the above-described operation, press molding by the molding die 5.6 is performed on the tip of the glass fluid 2, that is, the part excluding the cut marks 3, so that the resulting molded product 23 has surface marks such as shear marks. No defects occur.

Furthermore, the volume of the cavity formed by the molds 5, 6 can be set by the stroke of each cylinder 13, 16. i.e. set cylinder 13.16
By the stroke of each molded member 5,
The shortest approach width between the molding molds 5 and 6 is determined, and this regulates the distance between the molding surfaces of the molding molds 5 and 6. Therefore, since the wall thickness of the molded product 23 is determined by this molding surface interval, by setting the stroke of the cylinder 13, 16 according to the wall thickness of the molded product 23 to be manufactured, a predetermined wall thickness can always be achieved. A molded article having the following properties is obtained. Further, the surface shape and properties of the molded product 23 are determined by the molding surfaces 5a and 6a of the molded members 5 and 6, respectively. Furthermore, the outer peripheral shape of the molded product 23 is
The outer periphery of the molded product 21 is formed simultaneously with the cutting operation of the cutting ring 7.

Note that the press molding apparatus described above uses a mold that performs suppression operations from the left and right directions in response to the nozzle through which the glass fluid, which is the molding material, flows downward. The type and mold are not limited; for example, molds configured for transversely or obliquely supplied glass fluid may also be used.

Next, a specific example using the press molding method as described above will be described with reference to FIGS. 1 to 8.

(Example 1) Optical glass SF8 (
Tg=443℃, specific gravity 4.22), outer diameter 20m
Center thickness: 2.7 am, edge thickness: 1.29 mm.

Curvature R1=20m+s, R2=40mm, glass capacity 0
．． A reheat press preform having a convex meniscus shape and having a volume of 838 cc and a weight of 2.8111 g was molded.

The mold members 5 and 6 are made of 5US420J, and the respective molding surfaces 5a and 6a are polished to optical mirror surfaces. This mold member 5
．． Mold temperature of 6 is 400℃ (Tg of SF8 is 443℃)
Heat with heaters 30 and 31 so that the temperature is 3°C lower. In addition, the cutting ring 7 also has a heater 34.3 similar to the mold temperature.
Heat to 400°C in Step 5.

The stroke of the cylinders 13, 16 is equal to the stroke of each mold member 5,
The maximum approach width during the suppression operation of No. 6 was adjusted to 2.7 mm to obtain the desired wall thickness.

First, glass melted in a melting furnace (not shown) is heated to a glass fluid 2.
The viscosity of the glass fluid 2 was adjusted to about 1046 poise (815°±5°C), and as shown in FIGS. 3 flowed down from each molding surface 5a, 6a of the mold members 5, 6, the cylinders 13, 16 were actuated, and at the same time, the cutting blade 4 was also actuated. This cylinder 13.16
The operating pressures are 120 kg and 300 kg, respectively, and the operating speeds are 200 ms*/s for both.

Then, as shown in Figure $3, after the pressing operation of the mold member 5.6 against the glass fluid 2 is started, the cutting ring 7 is activated. The cutting ring 7 is made of SK3, and the time from the time when the pressing operation of the mold member 5.6 is completed until the cutting by the cutting ring 7 is completed is 0.2.
A controller (not shown) controls each cylinder 1 so that
Adjust the activation timing of 3°16.17. The operating pressure of the cylinder 17 that drives this cutting ring 7 is l
The operating speed is 200+sm/s. Further, as shown in FIG. 5, when the cutting operation by the cutting ring 7 is completed, the cutting of the glass flow 2 by the cutting blade 4 is also completed. Further, as shown in the figure, the cutting operation of the cutting ring 7 forms the outer peripheral shape of the part to be formed 21 and at the same time separates the part to be formed 21 and the cut piece 22.

In FIG. 5, the first mold member 5 and the cutting ring 7 are in an engaged state, but the cutting condition was good even when the two were only in contact with each other.

Next, while applying pressure to the cylinders 13 and 16, the state shown in FIG. As shown in FIG. 6, only the cylinder 16 was operated and the first mold member 5 was separated from the molded product 23. At this time, the molded product 23 remains held in the cutting ring 7 so that it does not fall off by itself.Next, the cylinder 17 is activated to pull back the cutting ring 7, and at the same time, the molded product 23 is taken out by a handling device (not shown). cylinder 13
is activated to return the first mold member 6 to its original position. Then, the cut piece 22 is removed by a cut piece removing device (not shown).

Thus, the molded product 23 obtained in this example has an outer diameter accuracy of ±0.0051, a center wall thickness of ±0.01+us, and a weight of Q,02g (±0.7%) with respect to the desired molded product.
], and there are no harmful surface defects such as shear marks, and sink marks are also within the range of each mold member 5 and 6.
It is within a maximum of 10 gm for the shape of
It could be used not only as a preform for reheat pressing, but also as an optical lens that does not require much precision.

FIG. 9 shows the cutting ring 7 and the first mold member 5 in this embodiment. It is a graph showing temporal changes in the temperature of the second mold member 6 and the glass that is the material to be molded. Incidentally, in this explanation, the time T shown in FIG. 8 is used.

Initially (T=O in FIG. 8), the first and second mold members 5, 6 are set at the glass transition point Tg of the glass material (SF8).
The viscosity of the glass fluid 2 flowing from the nozzle 1 shown in Fig. 2 is approximately 1046 poise (815° ± 5°C). It was adjusted as follows.

During the molding period (approximately 10 seconds) from the pressing start time T2 of the mold member 5.6 to the pressing end time T6, the glass in the molded part 21 is rapidly cooled due to the temperature difference between the mold members 5 and 6, and the viscosity becomes from lQ4.6 Boaz to 1QI4.5 Boaz or more.

In this embodiment, the mold members 5 and 6 and the cutting ring 7 are heated by respective heaters so as to be maintained at 400° C. until the end of the compression. At this time, the glass temperature of the molded product 23 is approximately the same as that of the mold member 5.6.

Further, when molding was carried out with the cutting ring 7 at 350° C. (the mold temperature was 400° C.), the same results as above were obtained.

(Example 2) In this example, optical glass F8 (Tg=445
℃, ratio i 3.38) using the same method as in Example 1 to obtain an outer diameter of 6 mm, a center wall thickness of 4 mm, and an edge thickness of 3.08 mm.
A biconvex preform for reheat press having a curvature of R+ = Rz = 10 mm, a glass capacity of 0.1 OOcc, and a weight of 422 mg was molded in a non-oxygen atmosphere.

In this example, the same mold member 5.6 as in Example 1 was used, and the heaters 30.31 were adjusted so that the mold temperature was 375°C (70°C lower than the F8 Tg of 445°C).

Further, the viscosity of the glass fluid 2 was adjusted to 105 poise (approximately 775'C) by melting the glass in a melting furnace (not shown).

Then, the operating pressure of each cylinder 13, 16, and 17 was set to 50 kg, 200 kg, and 50 kg, respectively, and press forming and cutting were performed in the same manner as in Example 1.
When the molded product 23 had an internal viscosity of 109 poise (approximately 540°C), it was removed from the second mold member 6.
The obtained molded product 23 has an outer diameter accuracy of ±0.01+u+, a center wall thickness of ±0.02, and a weight of ±0.02 with respect to the desired molded product.
The variation was within 3 mg (±0.3%), and the sink mark at the center of the surface was about 40 gm on average, and the surface condition was also good and the precision was sufficient to be used as a reheat press preform.

(Example 3) In this example, the same optical glass S as in Example 1 was used.
Using an F8 round bar, outer diameter 20mm, center wall thickness 3cm, edge thickness! , 6 ■, curvature R+ = 32 mm, glass volume io, 8
A convex lens of 93 cc and weight i of 2.92 g was molded in a non-oxidizing atmosphere.

The round rod made of SF8 had a diameter of Loam±1111, and after removing scratches and dust on the surface, it was heated in a heating furnace (not shown) to a viscosity of about 105 poise (about 775° C.).

The mold members 5 and 6 are made of tungsten carbide, the molding surfaces 5a and 6a are optical mirror surfaces, and the mold temperature is 510°C.
(corresponding to about 109 poise in terms of glass viscosity) using heaters 30 and 31. Also, the cutting ring is made of tungsten carbide like the mold members 5 and 6, and the cutting ring 7 is heated to 510°C using an external heater (not shown).
It was heated so that

Furthermore, in this example, since the molding was performed in a non-oxidizing atmosphere, the entire apparatus was covered with a cover and replaced with argon gas.

Then, the working pressures of each cylinder 13, 16, and 17 were set to 150 kg, 350 kg, and 100 kg, respectively.
Press molding and cutting were performed in the same manner as in Example 1. However, in this example, instead of the molten glass flow, a glass forest whose tip area was softened to the above-mentioned viscosity was used.

After press forming and cutting are completed, each cylinder 13° 16.
17 is the heater 30.31 with the pressure still applied.
The output of the heater for heating the cutting ring at 34.35 was gradually weakened until the temperature of the mold member 5.6 and the molded product 22 reached 370.
After cooling to a temperature of approximately 1QI 4.5 poise or higher (glass viscosity of 7 or more), the molded product 23 was taken out from the second mold member 6 in the same manner as in Example 1. At this time, Figure 1O (1
As shown in Figure 0 (a graph showing temporal changes in temperature of the mold member and glass during press molding in Example 3),
The temperature of the cutting ring 7 is always 5 to 5 higher than the temperature of the mold member 5.6.
Cooling was performed while adjusting the temperature to be 10°C higher.

The obtained molded product has an outer diameter accuracy of ±
The variation was within 0.005t+s, center wall thickness ±0.02mm, weight ±0.3mg, C±0.7%), the surface condition was good, and sink marks due to heat shrinkage were avoided by cutting ring 7. Since the cooling rate was slightly slower than that of the mold member 5.6, the cooling rate was concentrated at the center of the outer periphery, and the surface precision was very good, so that it could be used as is as a normal lens.

(Effects of the Invention) As explained above, according to the present invention, the following effects occur.

(1) There are no surface defects such as shear marks on the surface of the molded product.
Optical elements such as optical lenses or reheat press preforms with high dimensional and weight accuracy can be manufactured without any post-processing such as grinding or polishing after press molding.

Further, according to the present invention, since the cutting member is heated and cut, the properties of the cut surface, that is, the outer peripheral side surface of the molded product are good.

Also, if the cutting member is not heated and cutting is performed at a low temperature,
Since the outer periphery of the molded product solidifies first, the heat balance of the molded product itself is disrupted and more distortion occurs.In contrast, the present invention heats the cutting member and controls the temperature to an appropriate temperature before cutting. Since the entire molded product can be cooled evenly, there is less distortion.

Furthermore, by actively adjusting the temperature of the cutting member, it is possible to suppress the occurrence of sink marks, and it is possible to manufacture molded products with very good surface accuracy.

(2) Since the precision of the glass fluid used for molding is not required, the outflow device for molten glass etc. can be inexpensive and does not require high technology, and the flow rate of outflow glass due to fluctuations in the glass liquid level in the melting furnace. Since the melting furnace is flexible against temperature changes, the melting furnace may be inexpensive.

(3) In addition to molten glass, the glass material used for the m-shape may be a glass rod or sheet, and the accuracy of these materials is not particularly required.

(4) Since the glass fluid is directly press-molded and cut, small and thin molded products, which were conventionally difficult to press-form, can be easily produced with high precision.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1(a) is a schematic sectional view of a press molding apparatus showing an embodiment of the present invention. FIG. 1(b) is an enlarged sectional view of a main part of the apparatus shown in FIG. 1(a) with a heating device added thereto. Second
7 to 7 are sectional views of essential parts of the apparatus shown in FIG. 1, and show the operating state of the apparatus in the order of steps. FIG. 8 is a diagram showing a timing chart of each operating section of the press molding apparatus shown in FIG. 1. FIG. 9 is a graph showing temporal changes in temperature of the mold member and glass during press molding in the first example. FIG. 10 is a graph showing temporal changes in temperature of the mold member and glass during press molding in the third example. l... Nozzle 2... Glass fluid 3... Cutting mark 4... Cutting blade 5... First die member 6... Second die member 7... Cutting ring 21...・Part to be molded 22... Cut piece 23... Molded product 30... Heater 31 for heating the first mold member... Heater 34, 35 for heating the second mold member... Cutting ring Heating heater 40...Controller representative Patent attorney Jo Taira Yamashita Figure 1 (Q) Figure 1 (b) 2171 Figure 3 I\I Figure 4 Figure 5 Figure 6! A37 Me1 No. 8 drawing + T2 T3 T4 T5 Fig. 9 Opening of the upper corner of the mold for the sword arm and bottom shape Mr. Kunio Ogawa, Commissioner of the Patent Office, April 260, 1988.
Display of IT Patent Application No. 62-307412 2, Name of invention: light? Name of molding equipment for raw material (100) Canon Co., Ltd. 4, Agent address: 113-1 Toranomon 4, Toranomon 5-chome, Minato-ku, Tokyo
0 Mori Building Specification, I) Detailed Description of the Invention Column 6, Contents of Amendment (1) Specification - "For the molding method" on page 6, lines 6 to 7
should be corrected to "What is the molding method?" (2) On page 7, lines 4 to 8 of the specification, "On the other hand, ... is required." is corrected to the following sentence. "On the other hand, in the molding method described in JP-A No. 61-1:32523, fluid glass is punched out using a punching die, and only the punched portions are then press-formed. In order to obtain the meat I'll with high precision, it is necessary to increase the precision of the glass volume I11 of the punched part, and this requires high precision machining of the r-shaped shape of the glass material such as the rod supplied to the press molding. (3) Add the following sentence between line 708 and line 9 of the specification. ``In addition, as another conventional method for obtaining a glass molded product by press molding, in which the glass material supplied to the press molding is pressed from the side direction with respect to the moving direction of the glass material, there is -36136, or Japanese Utility Model Application Publication No. 49-361a75y.

Claims (5)

[Claims] (1) A pair of molding molds that are arranged opposite to each other so as to narrow the glass fluid and press the glass fluid to form a molded part, and a pair of molding molds that are provided on the outer periphery of the molding mold to separate the molded part and other parts. 1. A molding apparatus for an optical element, comprising: a cutting member for cutting and separating; and means for heating the cutting member. (2) It is characterized by comprising a temperature control means for changing the temperature of the mold according to the molding process, and a temperature control means for controlling the temperature of the cutting member according to the temperature of the mold. An apparatus for molding an optical element according to claim 1. (3) The apparatus for molding an optical element according to claim 1, wherein the glass fluid has a viscosity of 10 to 10^7 poise. (4) The optical element molding apparatus according to claim 2, wherein the glass fluid is a molten glass flow flowing down from an outflow nozzle of a glass melting furnace. (5) The optical element molding apparatus according to claim 2, wherein the glass fluid is made of a reheated rod or sheet-like glass material.