JPH01201036A - Production of optical element - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a method for manufacturing an optical element by press molding, and more specifically, a method for heating a glass fluid supplied to a mold for press molding. Regarding.

(Prior art) In recent years, high-precision optical elements that do not require post-processing such as grinding and polishing have been molded by press-molding a glass material placed in a mold with a predetermined surface material of 1 degree. A method has been developed to do so.

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

In the reheat press method, a necessary amount of glass material that has been melted and solidified in advance is cut, and the IrI treatment is performed by a method such as sanding to form a glass pellet, which is then placed in a mold and molded with the glass pellet. 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, molten glass is put into a mold and press-formed, without going through low-productivity steps such as cutting and sanding. A preformed product with a shape similar to (
There is a method of press-molding the obtained preform (preform) by placing the preform into a mold having an optically functional surface with the same or higher precision than the shape and surface precision of the final product.

(Problems to be Solved by the Invention) In the press forming method as described in U, when the glass fluid supplied to the mold is made to flow out from the outlet of the melting furnace, the glass fluid flows from the melting furnace to the mold. There are problems in that the surface of the glass fluid is cooled and hardened due to exposure to outside air and variations in the temperature distribution of the glass fluid occur. For this reason, a method has conventionally been adopted to solve the above-mentioned problems by directly heating the flame of a burner or the like using a glass fluid heater.

However, when heating the glass fluid with a burner etc.
Depending on the heating method used for flint-shaped glass, PB may be reduced and cloudiness may occur, and it is relatively difficult to uniformly heat the glass fluid. Further, when blowing a heated gas stream, extra force is applied to the glass fluid, causing fluctuations in the glass volume, resulting in a problem that the weight accuracy of the molded product becomes non-uniform. Additionally, this method has the problem that dirt and dust adhere to the glass surface, making it impossible for the molded product to maintain a predetermined optical precision.

Furthermore, when heating glass fluid by the method described above, a complicated heating device is required in addition to the molding device, and various restrictions are imposed on securing the installation space for this device. There was a problem.

The present invention was made to solve these problems, and uses a simple device to heat the glass fluid flowing out from one outlet of the melting furnace, suppressing the temperature drop of the glass fluid, and achieving a good press. It is an object of the present invention to provide a method for manufacturing an optical element in which a glass fluid at a temperature can be supplied to a mold.

(Means for Solving the Problems) In order to solve the conventional problems described above, the method for manufacturing an optical element of the present invention includes: A reflecting means is provided near the outflow L through which the glass fluid flows out, and the reflecting means reflects heat emitted from the glass fluid toward the glass fluid.

(Function) In the method for manufacturing an optical element configured as described above, the heat emitted from the glass fluid is reflected toward the glass fluid by the reflecting means provided near the outlet through which the glass fluid flows out. The glass fluid is heated by the reflected heat.

As this reflecting means, one constructed of a plurality of focal points can be used. By configuring the structure so that one focal point generated by this multi-focal point forming temporary reflective surface is formed in the part where the glass fluid is press-molded and heating that part, the glass fluid can be heated near the tip of the glass flow where the glass temperature drops the most. It is possible to intensively heat the glass flow in the press straight to Nff1 to the optimum press temperature.

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

FIG. 1(a) is a schematic cross-sectional view of the vicinity of a nozzle showing an embodiment of the present invention, and shows an example in which an elliptical curved plate is used as a reflecting means, and FIG. 1(b) and FIG. 1(c) are Figure 1(a)
FIG. 2 is an overall sectional view of the device showing an example of application of the device shown in FIG. 1, and FIGS. FIG. 2 is a sectional view of a main part of the device shown in the figure, and shows the operating state of the device in the order of steps.

In FIG. 1(a), 1 is a nozzle through which molten glass flows out from a melting furnace (not shown), and 2 is a glass fluid flowing out from this nozzle. After this glass fluid flows from the nozzle 1, it comes into contact with the outside air and the glass temperature drops the most near its tip.

Reference numeral 4 denotes a cutting blade that is provided on the F side of the nozzle 1 and that cuts the glass fluid 2 by opening and closing operations by a drive device (not shown). 5.6 is a mold for press-molding the glass fluid 2 cut by the cutting blade 4, and is composed of a first mold member 5 and a second mold member 6. These mold members 5.6
is configured to operate in a direction transverse to the glass fluid 2 as shown by an arrow by a drive stage to be described later.

Furthermore, in this embodiment, a reflecting means 3 made of a spheroidal elliptical curved plate having a reflective surface inside is fixed near the tip of the nozzle 1. In this reflecting means 3, the glass fluid 2 flowing down from the nozzle 1 is surrounded by the F2 reflecting surface, and one of the two focal points by the elliptically curved reflecting surface is focused on the glass fluid 2 near the outflow of the nozzle. and the other focal point is configured to be formed near the tip of the glass fluid. .

It is also possible to use a single reflection stage as shown in FIGS. 1(b) and 1(c). Anti-Q-FT' shown in Figure 1(b)
The stages are formed by forming a plurality of small, top-sided reflecting plates in the overall shape of an ellipse as described above, and are configured to form a focal point similar to the reflecting means described in 1. or,
The reflecting means shown in FIG. 1(c) is constructed so that a double focus is formed near the tip of the glass fluid 2 as shown.

With this configuration, the vicinity of the tip of the glass fluid 2 flowing MT' from the nozzle l, where the temperature drop is the most significant, that is, the part to be subjected to press molding, is heated intensively by the reflected heat of the heat emitted from the glass fluid 2, and the glass fluid 2 The temperature drop of the fluid 2 can be minimized. This is particularly effective for heating and maintaining the surface temperature of the glass fluid 2, and enables press molding by supplying the glass fluid between the mold members 5 and 6 with a relatively uniform temperature distribution.

1. The apparatus described above can be applied to a press molding apparatus as shown in FIG. 2, for example. In this press molding apparatus, the pair of mold members 5.6 are arranged so as to face each other so as to sandwich the glass fluid 2 from substantially perpendicular directions, as described above. Mirror-finished molding surfaces 5a and 6a are provided on opposing surfaces of each mold member 5.6. The first mold member 5 is held by a slider 14, which is slidably supported by a slide shaft 18. Reference numeral 16 denotes a cylinder that moves the slider 14 once, and the operation of this cylinder +6 causes the slider 14 to move in the direction of the sliding force of the slide shaft 18, thereby suppressing 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, 6Q of these mold parts 5.6 can be set by the stroke of each cylinder 13.16. Further, a cutting ring 7 having a cutting blade formed on the side of the first mold member 5 is provided on the outer periphery of the second mold +'j% material 6, and this cutting ring 7 slides on the slide shaft 18. The slider 15 is connected to a slider 15 which can be supported. Further, the slider 15 is connected to a cylinder 17, and the actuation of this cylinder 17 allows the cutting ring 7 to slide around the outer periphery of the second mold member 6 in a movement independent of the second mold member 6. can.

Furthermore, a heater 8.9 is provided inside each mold member 5.6. 10 and 11 are conductive wires connected to each heater. 19 is the base of the entire device, which firmly supports the cylinders 13, 16, 17 and the slide shaft 18.

Next, the operation of this apparatus will be explained using FIGS. 3 to 8.

FIG. 3 shows the state immediately before press molding, with glass fluid 2 flowing down from nozzle 1. When the tip of the glass fluid 2 flows down from the opposing molding surfaces 5a, 6a in the t direction, the first mold member 5 and the second mold member 6 begin to be suppressed. The operation start timings of these mold members 5.6 may be the same on both sides, but the press J-f and operation end r times of the mold members 5.6 against the glass fluid 2 may be at the same time or with an error of ±0.05 s at most. It is preferable to keep it within. If this error is large, only one side of the mold member 5.6 collides with the glass fluid 2, causing lateral wobbling of the glass fluid 2, which is not preferable.

Thereafter, as shown in FIG. 4, the mold member 5.6 keeps pressing the molded part 21 of the glass fluid 2 for a predetermined period of time, and during this period, the mold member 5.6 presses the glass fluid 2 onto both surfaces of the molded part 21. Suppression transfer is performed by the forming portions 5a and 6a.

The zero motion start time and cutting start time of the cutting blade 4 may be the same as the operation start time of the human-shaped member 5.6, but the time when the cutting blade 4 starts cutting the glass fluid 2 is the same as the time when the cutting blade 4 starts cutting the glass fluid 2.
6 must finish cutting the glass fluid 2 at the same time as the mold member 5.6 holds the glass fluid 2, or at least after the mold member 5.6 holds the glass fluid 2.

Thereafter, the cutting blade 4 is returned to its original state. Preferably, the time required from the start of operation of the cutting blade 4 to the end of cutting is set to 0.3 to 0.48.

The operation start timing of the cutting ring 7 is as shown in FIG.
It is preferable that cutting of the glass fluid 2 by the cutting blade 4 is completed at least in the outer peripheral cutting path 7'+iil of the part to be formed 21 by the cutting ring 7. By doing this, 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 1. The cut piece 22 cut by the IJ cutting rig 7 can be easily moved to the outside of the first mold member 5. Thus, the cutting ring 7 is connected to the second glue 1 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.

After that, the cutting ring 7 maintains the state at cutting path r, and cools the molded part 21 from the outer periphery by the temperature difference while holding the outer periphery of the molded part 21, and the vicinity of the outer periphery of the molded part 2I has a viscosity. increases and the shape becomes fixed. On the other hand, mold member 5.
After the suppression by 6, the molded part 21 is cooled from both surfaces due to the temperature difference between the mold member and the molded part 21, and its viscosity increases.
The surface shape is stabilized.

Next, as shown in FIG. 7, the first mold member 5 is returned to its original state. If the time to start operating the cutting ring 7 to its original state is at the same time as or after the time when the return of the first mold member 5 is completed, the part to be formed 21 is moved by the cutting ring 7 at the start of operation 11η of the cutting ring 7. It is held in place and does not fall off naturally.

Then, at the same time as the return path r 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.

Note that FIG. 8 shows a state in which the cutting ring 7 is returned to its original position, and at this time the molded product 23 is released from the holding of the cutting ring 7 and falls naturally. Therefore, it is desirable to take out the molded product 23 using a suction hand or the like before returning the cutting ring 7 to its original state.

In the above-described operation, press molding by the mold members 5 and 6 is performed on the portion of the glass fluid 2 excluding the tip, so that surface defects such as shear marks do not occur in the obtained molded product 23.

Moreover, the cavity volume 1i formed by the molding die 5.6
l can be set by the stroke of each cylinder 13.16. That is, the set cylinder 13.
The stroke of 16 determines the shortest approach width between each molding member 5.6 during compression, and this is the stroke of the mold 5.6.
The distance between each molded part is regulated. Therefore, since the wall thickness of the molded product 23 is determined by this molded part interval, the stroke of the cylinder 13.16 is determined by the molded product 2 to be manufactured.
By setting the thickness according to the thickness 1' of No. 3, a molded product always having a predetermined thickness can be obtained. In addition, the surface shape and properties of the molded product 23 are determined by the molded portion 5a of each molded member 5.6.
, 6 a. Furthermore, the outer peripheral shape of the molded product 23 is determined by the inner peripheral shape of the cutting ring 7, and the outer periphery of the molded product 21 is formed simultaneously with the cutting operation of the cutting ring 7.

Note that the reflection p stage in L is configured to intensively heat the glass fluid 2 at the focal point from the spheroidal reflection direction;
The present invention is not limited to such a configuration, but may be configured such that the glass fluid 2 is kept warm by reflecting heat over a relatively wide range of the glass fluid 2 using a reflecting plate of another shape.

Also, unlike the above-mentioned device, the mold member is not press-molded from the side direction against the glass fluid, but the mold is operated by pushing from the top direction, and a predetermined amount is applied to the lower mold. The present invention applies to a mold for press-forming after cutting off the glass fluid! A J-17' stage may also be applied.

Note that the present invention does not particularly limit the use of other heating means in combination with the glass fluid, for example, by heating the glass fluid in combination with a heating means such as a heater.

(Effects of the Invention) As explained above, according to the present invention, the above-mentioned anti-Q[- stage heats the glass fluid using the heat emitted from the glass fluid itself, without providing a separate heat source. , the glass fluid flowing down from the outlet can be supplied to the press molding device at a relatively uniform temperature.

Therefore, as seen in conventional heating devices, dust may adhere to the glass fluid or the glass fluid may change in quality.
Not only is no unnecessary external force applied to the glass fluid, the means of the present invention can be installed even in a relatively narrow space, and installation can be easily performed.

In addition, in the present invention, it is possible to effectively heat the necessary parts of the glass fluid, especially the vicinity of the tip of the glass fluid to be press-molded, by using a reflection plate that can form focal points at a plurality of locations as a reflection means. can.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of the vicinity of a nozzle showing an embodiment of the present invention, and shows an example in which an elliptical curved plate is used as a reflecting means. Fig. (a) is a schematic sectional view showing another embodiment different from the small reflecting means, Fig. 2 is an overall sectional view of the device showing an example of application of the device shown in Fig. 1, and Figs. 2 is a sectional view of a main part of the apparatus shown in FIG. 2, and shows the operating state of the apparatus in the order of steps. 1...Nozzle 2...Glass fluid 3...Reflection means 4...Cutting blade 5...First mold member 6...Second mold member agent Patent attorney Yama Ju Minoru Taira Figure 1 (b) Figure 1 (C) Figure 2 Figure 3 Figure 4 Figure 5 Figure 6

Claims (2)

[Claims] (1) In an optical element manufacturing apparatus in which a glass fluid is press-molded using a mold, a reflection means is provided near an outlet through which the glass fluid flows out, and the reflection means directs heat emitted from the glass fluid to the glass fluid. A method for manufacturing an optical element characterized by reflecting light toward. (2) The reflecting means is constituted by a multi-focal point forming plate, one focal point generated by the reflective surface of the focal point forming plate is formed near the outlet of the glass fluid, and the other focal point is formed in the press of the glass fluid. 2. The method of manufacturing an optical element according to claim 1, wherein the optical element is formed in a portion to be molded.