JPH03218931A - Device for producing formed optical glass - Google Patents

Abstract

PURPOSE:To produce a high-precision formed optical glass at a low cost by combining a means for supplying molten glass, a means for heating and holding a hot working jig, a means for pressing, reversing and heating a glass gob and a means for recovering the formed product to cause a specified action. CONSTITUTION:The second hot working jig 10 on a positioning member is sucked by the suction part 13a of a reverse arm 13 and held, and then the first hot working jig 9 is lifted by a lifting member 23 until a glass gob 25 is brought into contact with the forming surface of the second jig 10. The gob 25 is conveyed to the heating furnace 12 of a slow cooling chamber 3 with the contact surface with the first jig 9 turned upward and out of contact with the second jig 10. The initial section of the furnace 12 is used for initial slow cooling and kept at high temp., and consequently the gob 25 is heated and held at high temp. in this section. The contact surface of the gob 25 with the jig 9 is deformed into a specular surface by surface tension while passed through the section. The gob 25 is then passed through the slow cooling chamber 3 and sufficiently cooled, and a formed optical glass 26 having a good specular surface is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an apparatus for producing an optical glass molded body for reheat press molding, which is used to produce high-precision optical glass elements such as lenses and prisms.

2. Description of the Related Art In recent years, optical glass lenses have been trending toward aspheric surfaces that can simultaneously simplify the lens structure of optical instruments and reduce the weight of the lens portion. Manufacturing such an aspherical lens using only a polishing device would be difficult to process and mass-produce, so a manufacturing device using a mold is seen as promising.

The manufacturing equipment for optical glass molded bodies using molds is as follows.
The structure is such that a lump of optical glass is heated and molded with a mold release material such as aluminum hydroxide, magnesium carbide, or carbon applied or coated onto a mold that has been finished to the desired surface quality and precision in advance ( For example,
No. 160312).

Problems to be solved by the invention In the case of optical glass elements such as aspheric lenses and prisms,
The surface must be free from defects or adhesion of mold release agent, and must have the required surface roughness and surface precision, but the high temperature molten glass supplied to the thermal processing jig is in an extremely chemically active state. Therefore, in the conventional example described above, there is a problem in that it tends to react with or fuse with the heat processing jig.

To prevent this, it is effective to use the thermal processing jig without heating it, but the problem is that large wrinkle-like defects occur on the contact surface of the glass gop that comes into contact with the thermal processing jig due to heat shrinkage. There is.

That is, in order to obtain an optical glass molded body with no defects on the surface (for example, a mirror-like state with a surface roughness RMS of 0.1 μm or less) using conventional manufacturing equipment, it is necessary to perform further polishing or etching treatment. Therefore, it is not possible to sufficiently reduce manufacturing costs.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, an object of the present invention is to provide an apparatus for producing an optical glass molded body that can produce a high-precision optical glass molded body at low cost.

Means for Solving the Problems In order to solve the above problems, the first invention provides a supply means for supplying molten glass to a first thermal processing jig to create a glass gob, and a supply means for supplying molten glass to a first thermal processing jig to create a glass gob, and a supply means for supplying molten glass to a desired optical glass element and an approximate shape. a first heating means for heating a second thermal processing jig having a forming surface;
a holding means for holding a second thermal processing jig heated by the first heating means in a position with the molding surface facing downward; and a holding means for holding the second thermal processing jig heated by the first heating means; a pressing means for pressing and adhering the glass gob to the molding surface; a reversing means for reversing the second thermal processing jig on which the glass gob is pressed to a position in which the molding surface faces upward; the pressing means and the reversing means a second heating means for heating the glass gob placed on the second thermal processing jig and thermally deforming it into a desired shape; and a recovery means for recovering the optical glass molded body created on the second thermal processing jig. It is characterized by comprising means.

A second aspect of the invention is, in the above configuration, a first heating path conveying means for conveying the second thermal processing jig along the first heating means, and a second thermal processing jig supplied with a glass gob. a second heating path conveying means for conveying the heat along the second heating means, and between an exit side of the first heating path conveying means and an inlet side of the second heating path conveying means, A reversing means is provided for reversing the thermal processing jig and transferring it between both paths, and a second A collecting means for collecting the optical glass molded body from the thermal processing jig, and a reversing means for reversing the second heat processing jig from which the optical glass molded body has been collected and transferring it between both paths. It is characterized by

Further, in the second invention, the first heating path conveying means and the second heating path conveying means are arranged in parallel so as to support the second thermal processing jig from both sides, and are provided with heat resistance. It can be configured by a rod-shaped fixing member and a heat-resistant feeding member disposed between these rod-shaped fixing members and for intermittently feeding the second thermal processing jig on the rod-shaped fixing member. Further, the holding means is for holding the second thermal processing jig by vacuum suction, and can be integrally provided with the reversing means. Furthermore, the second thermal processing jig can have two molding surfaces that approximate the shape of the desired optical glass element.

A large wrinkle-like defect occurs on the contact surface of the glass gob that is in contact with an unheated thermal processing jig due to heat shrinkage, but the surface of the glass gob that is not in contact with the thermal processing jig is extremely smooth. It is a surface. The present invention has been made with attention to this point.

According to the first invention, after the molten glass supplied from the supply means is received by the first thermal processing jig, it is heated by the first heating means to form a molding surface having a shape approximate to the desired optical glass molded object. The forming surface of the second thermal processing jig held by the holding means in a downward position is brought into contact with the smooth surface of the glass gob to attach the glass gob to the second thermal processing jig. In this state, the second thermal processing jig is reversed by the reversing means, and the glass gob is replaced from the first thermal processing jig to the second thermal processing jig.

In the second thermal processing jig, the wrinkled surface of the glass gob faces upward, and by heating this with the second heating means, the wrinkled surface is transformed into a smooth surface by surface tension. Thereby, wrinkle-like defects on the surface of the glass gob in contact with the first thermal processing jig can be removed. On the other hand, the smooth surface of the glass gob is molded into a shape approximate to the desired optical glass molded body by the molding surface of the second thermal processing jig. The optical glass molded body is recovered from the second thermal processing jig by a recovery means.

According to the second invention, the first heating path conveyed along the first heating means and the second heating path conveyed along the second heating means are connected by two reversing means. As a result, the second thermal processing jig can be moved in a circular manner, so the number of second thermal processing jigs used can be minimized.

Furthermore, in the second invention, the heating path conveying means having the above-mentioned configuration allows the second thermal processing jig to be conveyed at a certain pinch interval, compared to moving the second thermal processing jig in a state in which they are in contact with each other. The number of second heat processing jigs used can be reduced, and since less friction occurs when transporting the second heat processing jigs, frictional deterioration of the second heat processing jigs can be reduced. Not only this, but also it is possible to avoid a situation in which dust, dust, etc. generated by the friction are attached to or mixed into the glass molded body. Further, the holding means having the above-mentioned structure allows the second thermal processing jig to be quickly held by suction, so that the glass gop can be replaced before the second thermal processing jig cools down.

Furthermore, by using the second thermal processing jig with the above configuration,
Even if the surface precision of one molding surface deteriorates due to adhesion of glass gobs, the other molding surface can be used, so the second heat processing jig can be used effectively without increasing the number of tools used. be able to.

EXAMPLE Hereinafter, an apparatus for manufacturing an optical glass molded body according to an example of the present invention will be described with reference to the drawings.

FIG. 1 shows the basic configuration of the manufacturing apparatus. In the figure, 1 is a heating chamber for heating the second thermal processing jig 10 (see FIG. 5(a)), 2 is a supply chamber for supplying the glass gob 25 to the thermal processing jig 10, 3, the thermally softened glass gob 25 on the thermal processing jig 10 is cooled without heating, that is, slowly cooled, and its free surface is made into a mirror surface by the action of surface tension, thereby forming an optical glass molded body 26. A slow cooling chamber 4 is a recovery chamber for recovering the slowly cooled optical glass molded body 26, and 5 is a transfer path for the thermal processing jig 10. In this embodiment, a heating chamber 1 and an annealing chamber 3 are provided in parallel, and a supply chamber 2 and a recovery chamber 4 are provided at both ends thereof, so that the second thermal processing jig 10 can be transferred in an annular manner.

The specific structure and operation of the apparatus for manufacturing an optical glass molded body having such a basic configuration will be explained with reference to FIGS. 2 to 4.

First, the means for transporting the second thermal processing jig 10 within the heating chamber 1 and the slow cooling chamber 3 will be explained using the heating chamber 1 shown in FIG. 2 as an example. In the same figure, 6 is a heating furnace (first heating means) l
This is the core tube inside the furnace.

The furnace core tube 6 is made of quartz with excellent heat resistance and corrosion resistance, and keeps the conveyance path of the thermal processing jig 10 in a clean state. Furnace tube 6
In order to convey the second thermal processing jig 10 at a certain pitch interval, two fixing rods (rod-shaped fixing members) 8 made of quartz square bars longer than the length of the furnace core tube 6 and one feeder are used. A rod (feeding member) 7 is arranged in the conveying direction. The two fixing rods 8 are held parallel to each other by a fixing jig (not shown) placed outside the furnace tube 9, and the distance between the two fixing rods 8 is set to be smaller than the diameter of the second heat processing jig 10. Fixed to short dimensions. These fixed rods 8 support the second thermal processing jig 10 from below on both sides.

The feeding operation of the feed rod 7 that moves the thermal processing jig 10 initially waits with the origin at a position below the second thermal processing jig 10 where it does not touch, and when the transport timing comes, it rises and moves the second heat processing jig 10. Lift up the processing jig 10 until it is separated from the fixed rod 8. Next, it moves by a predetermined pitch in the conveyance direction and descends to its original height. At this time, the second thermal processing jig 1
0 means that the fixed rod 8 has been moved in the transport direction by a predetermined distance of 7. The descending feed rod 7 moves in the opposite direction of transport and returns to the origin, completing one cycle of transporting the thermal processing jig. By repeating such operations, the second thermal processing jig IO is transported within the heating chamber 1 and the slow cooling chamber 3. Note that the second thermal processing jig 10 has its forming surface 10a in the heating chamber 1.
It is transported in a position with the side facing downward.

FIG. 3 shows the reversing means of the second thermal processing jig 10 and the glass gob supply means in the supply chamber 2. As shown, the reversing means is provided between the outlet side of the first heating path conveying means and the inlet side of the second heating path conveying means. The first heating path refers to the path indicated by a broken line in the heating chamber 1 shown in FIG. Similarly, the second heating path is a path along the heating furnace 12, which is the second heating means, and refers to the path shown by the broken line in the annealing chamber 3 in FIG.

In the figure, 9 is a first thermal processing jig, 12 is a heating furnace for heating and cooling the glass gob 25, that is, a heating furnace for slow cooling, and 13 is a second thermal processing jig 10, which is heated under vacuum. A reversing arm (reversing means) equipped with an adsorbing part (holding means) 13a for adsorbing and holding; 14 is a second thermal processing on the adsorbing part 13a (imaginary line in the figure) at the entrance of the slow cooling chamber 3; A feeding member that sends the jig 10 onto the fixed rod 8 in the heating furnace 12, 20 a molten glass supply furnace (supply means) that supplies molten glass 24 to the first thermal processing jig 9, 21 a nozzle thereof,
Reference numeral 22 denotes a transfer arm that moves the first thermal processing jig 9 between the position where the molten glass 24 is supplied (imaginary line in the figure) and the position above the push-up member (pressing means) 23 (solid line in the figure). be. The distal end portion of the transport arm 22 that holds the first thermal processing jig 9 has a shape that allows the upper end portion of the push-up member 23 to be inserted in the vertical direction. The second thermal processing jig 10 heated to a predetermined temperature by the heating furnace l1 in the heating chamber 1 is transferred onto a positioning member (not shown) by the feed rod 7 in the heating furnace 11. At approximately the same time as this operation, a certain amount of molten glass 24 from the molten glass supply furnace 20 is dropped from the nozzle 21 onto the first thermal processing jig 9 to form a glass gob 25, and the transfer arm 22 is rotated to form a glass gob 25. The first thermal processing jig 9 is positioned directly below where the second thermal processing jig 10 is positioned.

After the second thermal processing jig 10 on the positioning member is sucked and held by the suction part 13a of the reversing arm l3, the first thermal processing jig 9 is moved so that the glass gob 25 is moved to the second thermal processing jig by the push-up member 23. It is pushed up until it contacts the molding surface 10a of the tool 10. The surface of the second thermal processing jig 10 is coated with a chemically stable thin film that has good wettability to the glass gob 25.

Therefore, the glass gop 25 adheres to the second thermal processing jig 10 and is replaced from the first thermal processing jig 9, which has poor wettability. In this state, the reversing arm 13 is moved to the second thermal processing jig 1.
0 to a position where it can be immediately moved to the heating furnace 12, and the feeding member 14 feeds the second thermal processing jig 10 into the heating furnace 12 of the slow cooling chamber 3.

Thereby, the glass gob 25 can be quickly supplied to the heated second thermal processing jig 10, and the second thermal processing jig IO can be transferred from the heating furnace 11 to the heating furnace 12 in a short time. Therefore, the manufacturing tact time for the glass molded body 26 can be shortened. Further, the glass gob 25 is transported to the heating furnace 12 of the annealing chamber 3 in such a state that the contact surface with the first heat processing jig 9 faces upward and does not contact the second heat processing jig 1O.

Since the initial section of the heating furnace 12 is the initial section of the slow cooling process, it is naturally maintained at a high temperature, and the glass gob 25 is maintained at a high temperature in this section. That is, the heating furnace 12 in this section functions as a second heating means for the glass gob 25. While passing through this section, the contact surface of the glass gob 25 with the first thermal processing jig 9 is deformed into a mirror-like state due to the effect of surface tension. After that, at the stage of passing through the slow cooling chamber 3, that is, the final stage of the cooling process,
The glass gob 25 is sufficiently cooled to obtain an optical glass molded body 26 having a good mirror surface.

FIG. 4 shows a means for transporting the second thermal processing jig 10 and a means for recovering the glass molded body 26 in the recovery chamber 4. In the figure, reference numeral 15 denotes a suction member that holds the optical glass molded body 26 on the second thermal processing jig 10 by vacuum suction, and 16 denotes the optical glass molded body 26 transferred by this suction member 15. This is a collection member to be collected. The means for reversing the thermal processing jig IO in the recovery chamber 4 is the glass gob supply chamber 2.
The second thermal processing jig 10 carried out from the heating furnace 12 is attached to the adsorption part 13a of the reversing arm 13.
After being adsorbed and held by
It is sent to.

On the other hand, the glass molded body 26 cooled to the mold release temperature by the heating furnace 12 is held by suction by the suction member 15, and is carried out of the apparatus by the collection member 16.

5(a) to 5(C) show the second thermal processing jig 10. FIG. Figure 5 (a)
) and a molding surface 10 having an approximate spherical shape.
A is provided. The spherical accuracy of the molding surface 10a is RMS
By creating a mirror surface state of 0.1 μm or less, a highly precise optical glass molded body 26 can be manufactured. Fifth
By providing a spherical surface with the same radius on both the upper and lower surfaces as in the second thermal processing jig 10 shown in FIG. The other molding surface 10a has high surface accuracy.
can be used effectively without increasing the number of expensive heat-resistant and wear-resistant thermal processing jigs 10. Furthermore, as shown in FIG. 5(C), by providing molding surfaces 10a with different radius sizes on both sides, two glass molded bodies 26 with different shapes can be produced using one type of heat processing jig 10. This makes it possible to perform high-mix low-volume production without increasing the types of thermal processing jigs 10.

According to the apparatus for manufacturing a glass molded body having the above-described structure, it is possible to continuously manufacture the optical glass molded body 26 as a raw material for reheat press molding of a highly accurate optical glass element.

Effects of the Invention Since the present invention has the above-described structure and operation, it is possible to mass-produce glass molded bodies as raw materials for reheat press molding of optical glass elements with few defects on the surface without polishing as in conventional examples. This makes it possible to improve productivity and reduce manufacturing costs.

[Brief explanation of drawings]

FIG. 1 is a plan view showing the basic configuration of an apparatus for manufacturing an optical glass molded article according to an embodiment of the present invention, and FIG. 2 is a diagram showing the transportation of the second thermal processing jig in the heating chamber and slow cooling chamber of the same apparatus. 3 is a sectional view showing the means, FIG. 3 is a perspective view showing the reversing means of the thermal processing jig and the glass gob supply means in the glass gob supply chamber of the same apparatus, and FIG. A perspective view showing a device reversing means and an optical glass molded body recovery means, and FIGS. 5(a) to 5(C) are sectional views of a second thermal processing jig used in the same apparatus. 9 First thermal processing jig Second thermal processing jig Molding surface First heating means Second heating means Reversing means Holding means Supply means Pressing means Molten glass Glass gob Optical glass molded object

Claims (5)

[Claims] (1) A supply means for supplying molten glass to a first thermal processing jig to create a glass gob, and a second thermal processing jig for heating a second thermal processing jig provided with a molding surface having a shape approximating the desired optical glass element. a second heating means; a holding means for holding a second thermal processing jig heated by the first heating means in a position with the molding surface facing downward; and a second heating means held by the holding means. a pressing means for pressing the glass gob on a processing jig and adhering it to the molding surface; a reversing means for reversing the second thermal processing jig onto which the glass gob is pressed into a position with the molding surface facing upward; a second heating means for heating the glass gob placed on the second thermal processing jig by the pressing means and the reversing means and thermally deforming it into a desired shape; and an optical system formed on the second thermal processing jig. 1. An apparatus for producing an optical glass molded body, comprising a recovery means for recovering a glass molded body. (2) A first heating path conveying means for conveying the second thermal processing jig along the first heating means; and a first heating path conveying means for conveying the second thermal processing jig along the first heating means; A second heating path conveying means is provided, and a second thermal processing jig is inverted between the exit side of the first heating path conveying means and the inlet side of the second heating path conveying means. A reversing means is provided for transferring between the two paths, and between the exit side of the second heating path transport means and the entrance side of the first heating path transport means,
A collecting means is provided for collecting the optical glass molded body from the second thermal processing jig, and a reversing means is provided for reversing the second thermal processing jig from which the optical glass molded body has been collected and transferring it between both paths. 2. The apparatus for manufacturing an optical glass molded article according to claim 1. (3) The first heating path conveyance means and the second heating path conveyance means are arranged in parallel so as to support the second thermal processing jig from both sides, and are made of two heat-resistant rod-shaped fixing members. , disposed between these rod-shaped fixing members, and a second portion on the rod-shaped fixing member
Claim 2, characterized in that the heat processing jig is constituted by a heat-resistant feeding member that feeds the heat processing jig intermittently.
A manufacturing apparatus for the optical glass molded article described above. (4) Production of an optical glass molded article according to claim 2, wherein the holding means holds the second thermal processing jig by vacuum suction and is integrally provided with the reversing means. Device. (5) The apparatus for manufacturing an optical glass molded body according to claim 1, wherein the second thermal processing jig has two molding surfaces that approximate the shape of the desired optical glass element.