JPH01148715A - Die for forming optical element - Google Patents

Abstract

PURPOSE:To obtain an optical element having high precision and having no surface defect by press-forming falling fluid of glass with a pair of die and a guiding member and separating the formed part from other parts by cutting with a cutting member. CONSTITUTION:A pair of die 5, 6 is disposed so as to interpose a fluid of glass 2 falling down from a nozzle 1 of a melting furnace, and a guiding member 24 for guiding pressing operation of the die 5, 6 is disposed to the external periphery of the die 5, 6. A working surface of a formed part 21 is formed by pressing the glass fluid with the die 5, 6, and a part of the side surface of the external periphery of the formed part 21 is formed by the guiding member 24. After cutting the glass fluid 2 with a cutting edge 4, the side surface of the external periphery of the residual formed part 21 which has not been formed by the guiding member 24 is cut by operating a cutting member 7. Thus, an optical member is produced.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a mold for molding an optical element by press molding, and more specifically, the present invention relates to a mold for molding an optical element by press molding, and more specifically, the present invention relates to a mold for molding an optical element by press molding. The present invention relates to a mold for molding an optical element with good precision and weight accuracy, or a preform suitable for reheat pressing thereof.

(Prior Art) In recent years, press molding is performed by housing a glass material in a molding layer having a predetermined surface precision.

Methods have been developed for molding high-precision optical elements that do not require post-processing such as grinding and polishing.

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 a glossy 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 reheat press method, molten glass is put into a mold and press-formed into a final product, as in the above direct press method, without going through low productivity steps such as cutting and sanding. Preformed products with similar shapes (
There is a method in which the preform is obtained and then press-molded by placing the preform in a mold having an optical moat surface that is as precise as or higher than the shape and surface precision of the final product.

(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 small glass lumps before press molding, the mold release agent applied to prevent the glass and heating tray from fusing together bites into the surface of the molded product during pressing, significantly deteriorating the surface accuracy of the molded product. There is a problem with doing so.

In addition, in the method of press forming directly using molten glass,
When cutting with a cutting blade, cutting marks called shear marks are generated on the molded product, which causes a problem in that the surface precision of the molded product deteriorates. In addition, in this press molding method, the weight of the molded product is adjusted by cutting the molten glass flow, so the temperature change of the molten glass flow, the timing of cutting, or the type of glass flow! There is also the problem that weight fluctuations occur in the molded product due to JJ, 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 pressed, a phenomenon occurs in which excess glass in the mold cavity flows out from between the mold and the anvil facing the mold. 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 glass thickness between the above-mentioned molded product and the protruding portion changes, causing variations in the thickness of the molded product, making it difficult to adjust the weight 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 accuracy.

The present invention provides a mold that can smoothly perform the pressing operation of the mold used in this manufacturing method without causing axis misalignment, and can ensure optical axis precision of the molded product obtained. The purpose is to provide

(Means for Solving the Problems) In order to solve the above-mentioned conventional problems, the mold for molding an optical element of the present invention is such that each of the molding surfaces facing each other so as to narrow the glass fluid substantially absorbs the glass fluid. A pair of mold members arranged to press from a right angle direction to form a functional surface of the part to be molded; and an opening through which the glass fluid passes on the outer periphery of the mold member; a guide member that forms a part of the outer circumferential side surface of the part and guides the pressing operation of each of the mold members; and a guide member that operates to block the opening and the remaining part that is not formed by the guide member of the molded part. F) J-cutting member for cutting the outer circumferential side surface.

(Function) In the method for manufacturing an optical element configured as described above, each mold member constituting the pair of molding molds used is
and a second mold member, the respective molding surfaces of these mold members are arranged so as to face each other with the glass fluid in between. 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, if 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 above-mentioned arrangement, the mold member of t5f and the second mold member are placed above and below, respectively. It is also possible to arrange them in opposite directions.

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 pressing each mold member against 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 molded is determined by setting the cavity of the mold in advance. This cavity can be set by the interval between molding surfaces of each mold member during press molding. Excess glass generated when pressing each mold member freely flows out of 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.

Further, in the present invention, the guide member provided on the outer periphery of the mold member has a 4R configuration for guiding the pressing operation of the mold member.

In this type of mold, play occurs in each mold member due to changes in the temperature distribution, thermal expansion, or long-term use of the opposing mold members, resulting in misalignment of the axis of the mold members, resulting in the resulting molding being The guide member of the present invention prevents this axis deviation and makes it possible to manufacture an optical element having a predetermined optical axis accuracy.

Further, this guide member is configured such that the glass fluid supplied between each molding surface passes through an opening provided in the guide member, and also forms a part of the outer peripheral side surface of the part to be molded during press molding. It has the function of Therefore, if the forming surface of the outer circumferential side surface of this guide member is finished to a predetermined surface accuracy, a part of the outer circumferential side surface of the molded product can be used as a highly accurate optical functional surface.

Furthermore, the present molding mold includes a cutting member that operates to block the opening and cuts the remaining outer peripheral side surface of the part to be molded that was not formed by the guide member, and the cutting operation of the cutting member The remaining outer peripheral side surface not formed by the guide member is formed.

After forming the functional surface of the molded part by pressing the glass fluid with each mold member and forming a part of the outer peripheral side surface of the molded part with the guide member, the cutting member forms the functional surface of the molded part with the guide member. When the remaining outer peripheral side surface is cut, the molded part is cut and separated from the glass fluid, and the outer peripheral shape of the molded part is formed.

The molded product thus obtained is free from surface defects such as shear marks, since it is formed from a portion that does not contain cut marks of glass fluid, as described above.

Further, by forming the outer periphery of the molded part using the preset cavity, guide member, and cutting member, a molded product with high shape accuracy and weight accuracy can be obtained.

The machine surface of this molded product is formed by transferring the molding surface of each mold member, so 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.

Note that the viscosity of the glass fluid in the present invention is 10 to 10
7 boads is preferred. If the glass viscosity is lower than 10 poise, the glass flow becomes filamentous and the required glass capacity within the mold cavity becomes insufficient. It becomes difficult to cut the glass. Note that the optimum viscosity of these glass fluids is 103 to 105 poise.

Further, as the softened glass fluid in the present invention, as described above, in addition to molten glass, it may be obtained by reheating a previously formed glass rond or sheet. Note that the viscosity of these glass fluids is 10
3 to 105 poise is optimal.

In addition, the temperature of the molding die ranges from a temperature corresponding to 108 poise in terms of glass viscosity to a temperature 100 degrees Celsius lower than the glass transition point (hereinafter referred to as Tg, which corresponds to approximately 1013 in terms of glass viscosity) (Tg - 100 degrees Celsius). ) must be set within the range. If the mold temperature exceeds a temperature corresponding to 108 poise, the hardness of the glass surface in the molded part after press molding until cutting is slow, and when the outer periphery of the molded part is cut and formed, Predetermined shape accuracy and surface accuracy cannot be obtained. Furthermore, the molding surfaces of the crow and the mold tend to be fused together, which is undesirable. On the other hand, if the mold temperature is lower than Tg-ioo''C, cutting the outer periphery of the part to be molded will not only be difficult, but may also cause cracks at the cut portion.

The temperatures of the cutting member and the guide member are preferably equal to the mold temperature of the mold, so that the influence of temperature changes on the glass is similar to that of the mold.

Furthermore, the viscosity when taking out the molded product is 108 when this 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 it reaches a viscosity of about 1QI 4.5 poise. be able to.

Note that the press molding and subsequent cutting treatment in the present invention are preferably performed in a non-oxidizing atmosphere in order to maintain the life of the mold and cutting member.

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

FIG. 1 is a schematic cross-sectional view of a press-formed neck brace used in an embodiment of the present invention. However, a guide member, which will be described later, is omitted from this drawing. FIGS. 7(a) and 7(b) are perspective views showing the periphery of a mold including the guide member. However, Figure A shows a mold for molding a large lens, and Figure B shows a mold for molding a rectangular lens.

In FIG. 1, 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. 4 is provided below the nozzle 1, and the glass fluid 2 is opened and closed by a driver (not shown).
It is a cutting blade that cuts. The cutting blade 4 operates to cut the glass fluid 2 midway, thereby generating a cutting gA3.

The press molding apparatus shown in this embodiment is configured for a type in which the glass fluid 2 flows down from a nozzle 1.
A first mold member 5 and a second mold member 6 constituting a pair of molding molds are arranged to face each other so as to narrow the glass fluid 2 from a substantially right angle direction. 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, which is slidably supported by 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 pressed.

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, as shown in FIGS. 7(a) and (b), the outer periphery of the second mold member 6 is provided with a second mold member 6 from both sides in the horizontal direction.
A pair of guide members 24 having an arcuate cross section are fitted so as to sandwich them. This guide member 24 is fixed so as not to change its relative position with respect to the nozzle l, and the mold member 5.
During press molding of No. 6, the mold member 6 is configured to slightly protrude from the molding surface 6a of the mold member 6. The width of the portion protruding from the molding surface 6a is set to be slightly larger than the thickness of the desired molded product, and the molding surface 5a of the mold member 5 is selected during press molding of the mold member 5.6.
The tip portion of the guide member 24 is fitted into a guide groove 25 provided on the periphery of the guide member 24 . With such a configuration, during press molding of the mold member 6, the mold member 6 can be guided by the guide member 24 and moved, and the tip of the guide member 24 is fitted into the guide groove 25 of the mold member 5. , misalignment of each mold member 5.6 is prevented.

Further, a cutting member 7 is provided on the outer periphery of the mold member 6 via a guide member 24, and the cutting member 7 slides along the outer periphery of the mold member 6 in a portion of the cutting member 7 where the guide member 24 is not provided. It is formed to move, and an edge-shaped punching blade 7a is provided at the tip of this portion.

The cutting member 7 is connected to a slider 15 that is slidably supported on a slide shaft 18, and the slider 15 is further connected to a cylinder 17, and when the cylinder 17 is actuated, the cutting member 7 is moved to the second mold member 6. The second mold member 6 and the outer peripheral portions of the guide member 24 can be slid in an operation independent of the guide member 24.

Heaters 8 and 9 are provided inside each mold member 5 and 6. 10 and 11 are conductive wires connected to each heater. 19 is the base of the entire device, cylinder 1
3.16.17 and the slide shaft 18 are firmly supported.

Next, the operation of this device is shown in Figures 2 to 6, Figure 7, and Figure 8.
This will be explained using figures. FIGS. 2 to 6 are sectional views of essential parts showing the operating state of the present apparatus in each process order. however,
For convenience of explanation, the upper side of the dashed-dotted line shown in this figure shows a vertical cross-sectional view that clearly shows the operation of the cutting member 7, and the lower side of the same shows a cross-sectional view that clearly shows the operation of the guide member 24. The figure is shown below. FIG. 8 shows the operating part of this device, that is, the first mold member 5. It is a timing chart showing the operation timing of each part of the second mold member 6, the cutting blade 4, and the cutting member 7, and the horizontal axis shows time T. It can be controlled by a controller.

FIG. 2 shows the state immediately before press molding. Guide member 24
is configured such that its tip is located slightly closer to the mold member 5 than below the nozzle 1. The glass fluid 2 is flowing down from the nozzle 1 into the opening 26 of the guide member 24 . The tip of this glass fluid 2, that is, the cut mark 3
When the molding material flows downward from the opposing molding surfaces 5a and 6a, as shown in FIG. 2, the pressing operation of the first mold member 5 and the second mold member 6 is started. In this pressing operation,
The guide member 24 maintains its relative position with respect to the nozzle 1, and both mold members move toward each other. At this time, even if there is some axis misalignment in the mold member 5.6, the mold member 6 is guided by the guide member 24, and the guide groove 25 of the mold member 5 is fitted into the tip of the guide member, so that each molding surface The axis misalignment between 5a and 6a is corrected.

In FIG. 8, T=O indicates the start time of operation of both mold members 5.6. Although the start time of operation of both mold members 5.6 may be the same, It is preferable that the pressing operation end timing T2 be at the same time on both sides or within an error of at most ±0.05 seconds. If this error is large, only one of the mold members 5 and 6 will collide with the glass fluid 2, causing the glass fluid 2 to fall into the glass fluid 2. Lateral play occurs, which is undesirable.
Thereafter, as shown in FIG. 4, the mold members 5 and 6 keep pressing the molded part 21 of the glass fluid 2 for a predetermined period of time (T2 to T6), and during this period, both surfaces of the molded part 21 are pressed. On the other hand, each molding surface 5a.

Pressure transfer by 6a is performed.

The operation 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, but the time T2 when the cutting blade 4 finishes cutting the glass fluid 2 is when the mold members 5 and 6 are made of glass. It must be at the same time as or at least after holding fluid 2.

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 T of the cutting member 7 is such that the cutting of the glass fluid 2 by the cutting blade 4 is completed (T2) at least before the cutting member 7 finishes cutting the outer periphery of the part to be formed 21 (T3). ). By doing this, when the cutting operation of the cutting member 7 is completed, the glass fluid 2 is already cut off by the cutting blade 4, and the cut piece 2 cut by the cutting member 7 is
2 can be easily moved to the outside of the first mold member 5.

Note that FIG. 4 is a front view of the glass fluid state 15 before the cutting member 7 starts operating, as seen from the functional side of the molded part 21. As shown in this figure, the outer shape of the portion of the outer circumferential side surface of the part to be molded 21 that comes into contact with the guide member 24 is formed by the guide member 24 during the above-mentioned press molding.

The outer circumferential portion indicated by the dotted line in the figure corresponds to the outer circumferential side surface not formed by the guide member 24, and is cut and separated by the cutting member 7 to form the outer circumferential shape of the portion. As can be understood from FIG. 1, after the cutting is completed, the cut pieces 22 on the lower and upper sides of the molded part 21 are separated from the molded part 21 and fall naturally.

Thus, the cutting member 7 cuts the outer periphery of the molded part 21 while sliding along the outer periphery of the second mold member 6, and the molded part 2
The shape of the outer peripheral side surface that was not formed by the first guide member 24 is formed.

Thereafter, the cutting member 7 maintains the state at the end of cutting (T3), and cools the molded part 21 from the outer periphery due to the temperature difference while holding the outer peripheral side surface of the guide member molded part 21. The viscosity increases near the outer periphery and the shape is fixed. On the other hand, after being pressed by the mold member 5.6, the molded part 21 is cooled from both surfaces due to the temperature difference between the mold member 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 T7, and the start time for returning the cutting member 7 to its original state is at the same time as or after the return end time T7 of the first mold member 5, the cutting member Before the operation of step 7 starts, the part to be formed 21 is held by the cutting member 7 and the glass member 24, and does not fall off naturally.

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

In the above-mentioned operation, press forming using the molding die 5.6 is performed on the tip of the glass fluid 2, that is, the portion excluding the cut mark 3, so that the resulting molded product 23 may have shear marks, etc. No surface defects occur.

Also, the cavity formed by the molds 5, 6 can be set by the stroke of each cylinder 13, 16. That is, the distance between the molding surfaces of the molding dies 5 and 6 at the pressing end time T2 is determined by the set stroke of the cylinder 13, 16. Since the wall thickness of the molded product 23 is determined by this molding surface spacing, 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 maintained. A molded product is obtained.

In addition, the surface shape and properties of the molded product 23 are different from each molded member 5, 6.
It is determined by the respective molded parts 5a and 6a.

Further, the outer peripheral shape of the molded product 23 is determined by the inner peripheral shapes of the guide member 24 and the cutting member 7, and the outer periphery of the molded product 21 is finally formed simultaneously with the cutting operation of the cutting member 7.

Further, as described above, even if an axis misalignment occurs in the mold, the optical axis precision of the molded product can be improved by correcting the axis misalignment.

When manufacturing a rectangular lens, it is sufficient to construct a molding mold having a rectangular molding surface as shown in FIG. 7(b). The same parts as in a) are given the same reference numerals. Generally, such a square lens undergoes complicated thermal deformation and is prone to defects such as sink marks, making it difficult to mold. This makes it difficult for deformation to occur, making it easier to mold.

In such a method of forming the outer circumferential shape, the portion formed by the guide member 24 can have a more accurate surface texture than the side surface formed by the cutting member 7.

Although the glass fluid applied to the press forming apparatus described above is molten glass flowing out from a melting furnace through a nozzle, it is also possible to reheat a glass material in the form of a rod or sheet that has already been formed. It is also possible to use a softened glass material made fluid by inserting it between molds.

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
m, center thickness 2.7 Ilm, edge thickness 1.23 m, curvature RI = 201 layers, R2 = 40 IIm, glass capacity 0
．． A convex meniscus preform for reheat press with a volume of 638 cc and a weight of 2.68 g was molded. The mold members 5.6 are formed from 5US420J, and each molding surface 5.
a and 6a are polished to optical mirror surfaces. This mold member 5, 6
mold temperature is 400℃ (43℃ from Tg of SF8 = 443℃)
Heat it with a heater 8.9 until it reaches a low temperature (If). Also, the stroke of the cylinder 13°16 is adjusted to each mold member 5.
, 6 is adjusted so that the maximum approach width during the pressing operation is 2.7 m, so that the desired wall thickness can be obtained.

First, glass melted in a melting furnace (not shown) is heated to a glass fluid 2.
The viscosity of the solution was adjusted to about 104.6 bores (815°±5°C), and the solution was discharged from nozzle 1. Next, the second
As shown in the figure and FIG. 3, when the cut mark 3 at the tip of the glass fluid 2 flows down from the molding surfaces 5a and 6a of the mold members 5 and 6, the cylinders 13 and 16 are actuated, and at the same time Cutting blade 4 was also activated. This cylinder 13.1
6(7) The working pressures are 120 kg and 300 kg, respectively, and the working speeds are both 200 IIm/s.

Then, as shown in FIG. 3, after the pressing operation of the mold members 5 and 6 against the glass fluid 2 is started, the cutting member 7 is activated. The cutting member 7 is made of SK3, and is controlled in advance by a controller (not shown) so that the time from the time when the pressing operation of the mold members 5 and 6 is completed until the cutting by the cutting member 7 is completed is 0.25. cylinder 13.1
The operating pressure of the cylinder 17 that drives this cutting member 7, which adjusts the operating timing of 6.17, is 100 kg.
The operating speed is 200+*m/S.

Further, as shown in FIG. 5, when the cutting operation by the cutting member 7 is completed, the cutting of the glass flow 2 by the cutting blade 4 is also completed. Furthermore, as shown in the figure, the cutting operation of the cutting member 7 forms the outer peripheral side surface of the part to be formed 21 that is not formed by the guide member 24, and at the same time, the part to be formed 21 and the cut piece 22 are separated.

In addition, in FIG. 5, the first mold member 5 and the cutting member 7
Although they were in an interlocking state, the cutting condition was good even when the two sides were just in contact.

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 is held by the cutting member 7 and the guide member 24 so that it does not fall off by itself.Next, the cylinder 17 is activated to pull back the cutting member 7, and at the same time, the molded product 23 is molded by a hand member device (not shown). The product 23 is removed and the cylinder 13 is actuated 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 ±0.0051111, a center wall thickness of ±0.01 m, and a weight of 0.02 g (±0.
7%), no harmful surface defects such as shear marks occurred, and sink marks were also within 5% of each mold member.
．． It was within 10 pm at maximum with respect to the shape of No. 6, and could be used not only as a preform for reheat press but also as an optical lens that does not require much precision.

FIG. 9 is a graph showing temporal changes in temperature of the first mold member 5, the second mold member 6, and glass as the material to be molded in this example. 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 (T of SR8).
g = 443°C) was adjusted to 400°C, which is 43°C lower.

Also, the viscosity of the glass fluid 2 flowing from the nozzle 1 shown in FIG. 2 is approximately! The temperature was adjusted to 046 bores (815°±5°C). End time T of pressing operation of the mold members 5 and 6
During the molding period (approximately 10 seconds) from 2 to return operation start time T6, the J lath of the molded part 21
It is rapidly cooled due to the temperature difference, and the viscosity increases from 1046 boazz to 1QI4.5 poise or more. In this embodiment, the mold members 5.6 are heated by heaters 8.9 so as to be maintained at 400° C. until the end of pressing, and at this time the glass temperature of the molded product 23 is approximately the same as that of the mold members 5, 6. It becomes warm.

(Example 2) In this example, optical glass F8 (Tg=445
℃, specific gravity 3.36), the outer diameter is 6 mm, the center wall thickness is Arx, and the edge thickness is 3.0 using the same method as in Example 1.
A double-convex preform for reheat press was molded with 8 layers, a curvature of R1=R2=10 m+g, a glass volume fiO of 100 cc, and a weight percentage of 337 mg.

In this example, the same mold members 5 and 6 as in Example 1 were used, and the heater 8.9 was adjusted so that the mold temperature was 375°C (70°C lower than R8's 7g445°C). .

Further, the glass fluid 2 melted in a melting furnace (not shown) has a viscosity of 10295 to 1031 poise (1080°C to
The temperature was adjusted to 1050°C. Then, the operating pressure of each cylinder 13, 16, 17 is 50 kg, respectively.
200 kg and 50 kg, press molding and cutting were performed in the same manner as in Example 1, and when the internal viscosity of the molded product 23 reached 109 poise (approximately 540°C), the mold member 6 of FF12 was also taken out. , the obtained molded product 23 has an outer diameter accuracy of ±0.0 with respect to the desired molded product.
15m, center thickness: ±0.021 Weight: ±3mg (±0
．． 3%), and the sink mark at the center of the surface was about 40 gm on average, and the surface condition was good enough to be used as a preform for reheat press.

(Example 3) In this example, the same optical glass S as in Example 1 was used.
Using an F8 round bar, the outer diameter is 20III1. Center thickness 3a
A convex lens with m, edge thickness, S mm, curvature R1 = 32 mm, glass volume io, 893 cc, and weight 2.92 g was molded in a non-oxidizing atmosphere.

The round bar made of SF8 has a diameter of 10mm±1m,
After removing scratches and dirt from the surface, heat it in a heating furnace (not shown).
The mixture was heated to a viscosity of approximately 0.05 poise (approximately 775°C).

The mold members 5 and 6 are made of tungsten carbide, and the molding surfaces 5a and 6a are optical mirror surfaces.

Heaters 8 and 9 were used to heat the mold to a temperature of 510° C. (corresponding to about 109 poise in terms of glass viscosity). Also, the cutting member 7 is made of tungsten carbide like the mold members 5 and 6, and the cutting member 7 is heated by an external heater (not shown).
It was heated to 00°C.

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

Then, the working pressures of each cylinder 13, 16, and 17 were set to 170 kg, 350 kg, and 150 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 rod whose tip portion had been softened to the above-mentioned viscosity was used.

After press forming and cutting are completed, each cylinder 13° 16.
17, while keeping the pressure applied, gradually weaken the output of the heaters 8, 9 and the external heater for heating the cutting member, until the temperature of the mold members 5, 6 and the molded product 22 reaches 400°C (approximately IQ + 4 in terms of glass viscosity). After cooling to .5 poise or higher),
The molded product 23 was taken out from the second mold member 6 in the same manner as in Example 1. The obtained molded product has an outer diameter accuracy of ±0.005+*m and a center wall thickness of 100, relative to the desired molded product.
O1+sm Weight: ±0.025 g (±0.85
%), the surface condition was good, and there was almost no surface erosion due to sink marks, and the lens could be used as it is without particularly requiring high precision.

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

(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.

(2) Since the glass fluid used for molding does not require much precision, the device for discharging molten glass or the like may be inexpensive and does not require high technology. Furthermore, since the melting furnace is flexible in response to changes in the flow rate and temperature of the outflowing glass due to fluctuations in the glass liquid level in the melting furnace, the melting furnace may also be inexpensive.

(3) In addition to molten glass, the glass material used for molding may be in the form of 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 manufactured with high precision.

In particular, according to the present invention, the optical axis precision of the molded product can be improved by correcting the axis misalignment of the mold using the guide member. In addition, the outer peripheral side surface of the molded product formed by the guide member of the present invention can be finished with a highly accurate surface texture as required, unlike those formed by cutting with a cutting member. It can also be actively used for functionality.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view of a press molding apparatus showing an embodiment of the present invention. FIGS. 2 to 6 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. FIGS. 7(a) and 7(b) are perspective views showing the periphery of the mold. 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. 1... Nozzle 2... Glass fluid 3... Cutting mark 4... Cutting blade 5... First die member 6... Second die member 7... Cutting member 21...・Molded part 22...Cut piece 23...Molded product 24...Guide member 25...Guide groove agent Patent attorney Yamashita Seki Box 1 Figure 5 Figure 8 TI T2 T3 T4 T5 Fig. 9 Between the crow and the angle of 1 11 Current affairs month procedure Nei City official document (Power°ヱ0 February 26, 1986 E1 Kunio Ogawa, Commissioner of the Patent Office 1, Patent application for indication of the incident No. 62-304571 No. 2, Name of the invention: Mold for molding optical elements 3, Relationship to the amended case Patent applicant name: Canon Co., Ltd. 4, Agent address: 5-13-1 Tora-mon, Minato-ku, Tokyo No. Toranomon 4o
Mori Building 6, Detailed description of the invention column, Brief description of drawings column, Drawing 7, Contents of amendment (+) "Figure 4" on page 20, line 3 of the specification of the specification to be amended. "Figure 4 (
a)” and correct + Tyu. (2) Correct ``Figure 4'' on page 21, line 9 of the specification box to ``Figure 4 (b)'' by ::1. (3) The ``operating state'' on page 35 line 5 of the specification cylinder is indicated.
The cross-sectional state in Figure (a) is shown. ” he corrected. (4) Figure 4 of the drawings has been corrected as Figure 4(a) and Figure 4° has been revised as Figure 4(b), respectively, as shown in the attached sheets. Figure 4 (a) Figure 4 (b)

Claims (6)

[Claims] (1) A pair of mold members for molding arranged so that the molding surfaces facing each other so as to narrow the glass fluid press the glass fluid from a substantially perpendicular direction to form a functional surface of the molded part; A guide member having an opening through which the glass fluid passes on the outer periphery of the mold member, forming a part of the outer peripheral side surface of the molded part and guiding the pressing operation of each of the mold members; A mold for molding an optical element, comprising: a cutting member that operates to cut off the remaining outer peripheral side surface of the portion to be molded that is not formed by the guide member. (2) The outer periphery of the mold member is configured by combining the guide member and the cutting member in pairs so as to face each other. A mold for molding optical elements. (3) The mold for molding an optical element according to claim 1, wherein the glass fluid has a viscosity of 10 to 10^7 poise. (4) The mold for molding an optical element 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 mold for forming an optical element according to claim 2, wherein the glass fluid is made of a reheated rod or sheet-like glass material. (6) The glass fluid is heated at a temperature corresponding to a glass viscosity of 10^8 poise and a glass transition point (about 10^1 in glass viscosity).
3. The mold for forming an optical element according to claim 2, wherein the mold is press-molded at a temperature 100° C. lower than 3 poise.