JPH0578135A - Method for forming optical element - Google Patents

Abstract

PURPOSE:To form an optical element having good surface condition in high accuracy. CONSTITUTION:A first heating furnace 4, first forming chamber 5, feeding table 6, second heating furnace 7 and second forming chamber 8 are successively arranged along a carrying rail 3 of a carrying dish 10. A plate-like glass forming raw material 11 is retained by the carrying dish 10 and heated and softened by the first heating furnace 4 and then a recessed part 11a is formed in the plate-like glass forming raw material 11 by a mold member 12 of the first forming chamber 5. A globular glass forming raw material 15 from a chute 20 is dropped on the feeding table 6 and positioned and fixed on the recessed part of the plate-like glass forming raw material 11. The plate-like glass forming raw material 11 and globular glass forming raw material 15 are simultaneously heated and softened by the second heating furnace 7 and then subjected to press forming by the upper mold 16 and lower mold 17 of the second forming chamber 8 to provide the optical element 19. Since the globular glass forming raw material 15 is fed to the plate-like glass forming raw material 11 without heating, foreign matters are not attached to the globular glass forming raw material 15 in feeding and can be kept in good surface condition. The globular glass forming raw material 15 can be formed in high accuracy, because the glass forming raw material 15 is positioned by the recessed part 11a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molding method for pressing a glass molding material into an optical element, and more particularly to an optical element molding method suitable for press molding an aspherical lens.

[0002]

2. Description of the Related Art As a method for accurately molding an optical element such as an aspherical lens, a method is known in which a heat-softened glass molding material is set between a pair of molds and pressed.
JP-A-60-186423 describes a conventional method for performing such press molding. In this press-molding method, a spherical pre-molded material is used as a glass molding material, and the spherical glass molding material is heated and softened and then spontaneously dropped by a chute into a lower mold for press molding.

[0003]

However, in the above-mentioned conventional method, when the softened spherical glass molding material rolls on the chute, the mold release agent or foreign matter of the chute easily adheres. The surface condition of the molding material is significantly impaired. Therefore, it is possible to clean the chute surface, but in this case, there is a disadvantage that the glass molding material adheres to the chute due to its viscosity and does not roll. The present invention has been made in consideration of the above circumstances, and there is no surface contamination of spherical glass molding material, and molding of an optical element that can be reliably supplied into the mold to perform high-precision press molding. The purpose is to provide a method.

[0004]

To achieve the above object, the present invention provides a step of heating and softening a plate-shaped glass forming material while holding the outer peripheral portion of the glass-shaped material on a carrying tray, and a plate-shaped glass after heating and softening. First to press the upper surface of the molding material to form a recess
Forming step, a step of supplying a spherical glass forming material to the concave portion of the glass forming material, a step of heating and softening the plate-shaped glass forming material and the spherical glass forming material at the same time, A second molding step of simultaneously press-molding both glass molding materials into a lens shape is provided.

[0005]

In the above structure, since the spherical glass molding material is supplied to the recess of the plate-shaped glass molding material in an unsoftened state that is not softened by heating, the surface of the glass molding material is free from mold release material and foreign matter, and is excellent. It is placed in the concave portion of the plate-shaped glass material while keeping the surface state. Then, after heating and softening these plate-shaped glass molding material and spherical glass molding material,
Since it is press-molded in the mold, it can be molded with high accuracy even if it is an aspherical surface.

[0006]

Embodiment 1 FIG. 1 shows a molding apparatus used in an embodiment of the molding method of the present invention. In this molding apparatus, a transport tray 2 is arranged on the upstream side (left end side) and a storage tray 9 is disposed on the downstream side (right end side) of a base 1 having a nickname, and a transport tray 2 is conveyed between these trays 2 and 9. The rail 3 is constructed so as to extend around it. Then, along the longitudinal direction of the transport rail 3, the first heating furnace 4, the first molding chamber 5, the supply table 6, the second
The heating furnace 7 and the second molding chamber 8 are arranged in this order on the base 1. Each of the first and second heating furnaces 4 and 7 is for heating and softening the glass molding material, and is provided with a heater inside. The first molding chamber 5 has a plate-shaped glass molding material 11 as described later.
A concave portion 11a is formed in the inner surface of which a mold member 12 having a convex lower surface is hung. A lift cylinder 14 is provided in the base 1 located below the mold member 12.
A push-up pin 13 is attached to No. 4. The push-up pin 13 moves up and down to convey the glass molding material 1
It raises and lowers 0.

The supply table 6 is provided on the downstream side of the first molding chamber 5, stops the carrier tray 10 for a while, and supplies the spherical glass molding material 15 to the carrier tray 10 in this stopped state. Is.

In order to carry out such supply, a chute 20 for dropping the spherical glass molding material 15 is provided above the chute 20. The second molding chamber 8 is for molding an optical element of a predetermined shape by pressing, and inside thereof, an upper mold 16 and a lower mold 17 having molding surfaces on their facing surfaces are arranged opposite to each other. In the present embodiment, the upper mold 16 is fixedly provided in the molding chamber 8, but the lower mold 17 is attached to the press cylinder 18, and the press molding is performed by the upward movement of the lower mold 17. ..

Next, a molding method using the above molding apparatus will be described. In this method, a plate-shaped glass molding material 1
1 and a spherical glass forming material 15 are used as glass forming materials, and these glass forming materials 11 and 15 are conveyed by a conveying tray 10 that moves along the conveying race 3. The transport tray 10 is supplied onto the transport tray 2 while holding the outer peripheral portion of the plate-shaped glass molding material 11. Then, the transfer tray 10 is transferred into the first heating furnace 4 and stopped, and heating by the heating furnace 4 is performed. The plate-shaped glass molding material 1 held on the transport tray 10 by this heating
1 is heat-softened, and after this heat-softening, the transport tray 10 is
It is conveyed into the molding chamber 5 of. In the first molding chamber 5, the lifting cylinder 14 operates to raise the push-up pin 13,
Lift the carrier tray 10. As the carrier tray 10 rises, the plate-shaped glass molding material 11 in a heat-softened state is transferred to the mold member 12.
Since it comes into contact with, the concave portion 11a is formed in the substantially central portion thereof. After the formation of the recessed portion 11a, the push-up pin 13 descends, the transport tray 10 returns to the transport rail 3, and the transport rail 3 moves the transport tray 10 onto the supply table 6 and then stops. After this stop, the spherical glass molding material 15 rolls on the chute 20 and falls into the concave portion 11a of the plate-shaped glass molding material 11 to be positioned and fixed. In this case, since the spherical glass molding material 15 supplied is not heated and has not been softened,
Roll the chute 20 smoothly. Further, since it is not necessary to apply a release agent or the like to the chute 20 and the chute surface can be cleaned, the spherical glass molding material 15 can be supplied with the surface being in a good state.

In this way, the spherical glass molding material 15
After being positioned and fixed in the concave portion 11 of the plate-shaped glass forming material 11, the transfer tray 10 moves on the transfer race 3 to move to the second position.
It is conveyed to the heating furnace 7 and stopped. In the second heating furnace 7, the plate-shaped glass forming material 11 and the spherical glass forming material 15 are simultaneously heated and softened by heating. After this heating and softening, the transport tray 10 moves into the second molding chamber 8 and stops. After this stop, the press cylinder 18 operates, and the lower die 17 enters the transport tray 10 to integrally raise the plate-shaped glass forming material 11 and the spherical glass forming material 15. Then, press molding is performed by the lower mold 17 and the upper mold 16 to mold the optical element 19 having a predetermined shape in which the plate-shaped glass molding material 11 and the spherical glass molding material 15 are integrated. In molding the optical element 19, the spherical glass molding material 15 is accurately positioned by the concave portion 11a of the plate-shaped glass molding material 11, so that the molding can be performed with high accuracy. Also, the optical element 1
Since the diameter of the spherical glass molding material 15 is irrelevant to the volume of 9 and only its thickness is changed, molding can be easily performed. After the molding is completed as described above, the optical element 19 is held by the carrying tray 10, transferred to the storage tray 9, and stored.

[0011]

As described above, according to the present invention, a plate-shaped glass molding material is heated and softened to form a concave portion, and a spherical glass molding material is supplied to the concave portion to position and fix it, and these are simultaneously heated. Since it is softened and press-molded into an optical element having a predetermined shape, the spherical glass molding material can be molded while the surface condition is good, and high-precision molding is possible.

[Brief description of drawings]

FIG. 1 is a side view of a molding apparatus applied to an embodiment of the present invention.

[Explanation of symbols]

 4 First Heating Furnace 5 First Forming Chamber 6 Supply Stand 7 Second Heating Furnace 8 Second Forming Chamber 10 Conveyor Dish 11 Plate-shaped Glass Forming Material 11a Recess 15 Spherical Glass Forming Material

Claims (1)

[Claims] 1. A step of heating and softening a plate-shaped glass molding material while holding an outer peripheral portion thereof on a carrying tray, and a step of pressing a top surface of the plate-shaped glass molding material after the heating and softening to form a recess. Forming step, a step of supplying a spherical glass forming material to the concave portion of the glass forming material, a step of heating and softening the plate-shaped glass forming material and the spherical glass forming material at the same time, And a second molding step in which both glass molding materials are simultaneously press-molded to form a lens shape.