JP3162178B2 - Method for molding optical glass element - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming an optical glass element such as a lens and a prism.

[0002]

2. Description of the Related Art As a molding method of an optical glass element, for example, a technique disclosed in Japanese Patent Application Laid-Open No. Hei 3-60435 is known. That is, while holding the molten glass in a non-oxidizing atmosphere, it is coated with a chemically stable thin film and supplied to a thermal processing jig having a desired shape and optical surface,
The optical glass molded body that is thermally deformed on the optical surface of the thermal processing jig and the thermally deformed optical glass molded body is press-molded. Each of these steps is performed in the same apparatus maintained in a non-oxidizing atmosphere. It is.

[0003]

However, the above prior art has the following problems. In other words, molten glass is supplied to a thermal processing jig in a non-oxidizing atmosphere, and is thermally deformed and molded. The molten glass is exposed to the surface of the molten glass by contact with the thermal processing jig. However, there is a problem that cloud is generated on the contact surface because the gas expands as a gas.

[0004] The present invention has been made in view of the above-mentioned problems of the prior art, and has as its object to provide a molding method for obtaining a good optical glass element free from clouding.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention is to supply molten glass flowing out of a nozzle tip by a predetermined amount into a conveying member from above the conveying member, A step of cooling and solidifying the lower side of the glass, a step of heating and softening the glass material in the conveying member after the supply, and a step of press-molding the heat-softened glass element material with a pair of upper and lower forming dies, An optical glass element was formed. Further, the present invention provides a step of supplying a predetermined amount of molten glass flowing out from the nozzle tip into the transport member from above the transport member, cooling and solidifying a lower side of the supplied molten glass, A desired optical glass element is formed by a step of heating and softening the glass material in the member and a step of press-forming the heated and softened glass material in the conveying member using a pair of upper and lower molds. Further, the present invention provides a step of supplying molten glass flowing out of the nozzle tip by a predetermined amount from above the conveying member into the conveying member, cooling and solidifying a lower side of the supplied molten glass, The steps of heating and softening the glass material in the member and deforming the glass material under its own weight to form a convex portion on the lower surface, and pressing the heat-softened glass material with a pair of upper and lower forming dies in the conveying member are desired. Was formed.

[0006]

According to the above-described molding method, the molten glass flowing out of the nozzle is supplied into the conveying member and the lower side is cooled, so that the glass material can be held in the conveying member. The side can be cooled below the transition point, and the moisture adsorbed on the molten glass surface can be evaporated by heating by holding the part other than the molding surface inside the transport member so that the molding surface is not in contact. Thereafter, press molding is performed using a pair of upper and lower molding dies, so that a good glass element free from defects such as clouding can be obtained.

[0007]

Embodiment 1 FIG. 1 is a sectional view of a main part of a molding apparatus 100 for carrying out an optical glass element molding method of the present embodiment. In the figure, reference numeral 1 denotes a glass melting furnace for melting a glass material, which is provided with a nozzle 3 for supplying a molten glass 5 into a conveying member 6 below, and a heater 2 and a nozzle heater 4 around the periphery. . A movable conveyor 13 on which a plurality of transport members 6 are placed is provided in the molding apparatus 100. Further, in the forming apparatus 100, preheating heaters 16 and 17 for performing a preheating process and heaters 18, 19, 20, and 21 for performing a thermal deformation process are provided. A cooling nozzle 7 for supplying cooling air is provided at a position corresponding to the nozzle 3 of the melting furnace 1 and below the conveying member 6. Reference numerals 10 and 11 denote a pair of upper and lower molding dies, which are provided with heaters 22 and 23 around the periphery thereof. The glass material 8 in the conveying member 6 is press-molded and cooled in the annealing furnace 15 to cool the desired optical glass element 14 Is what you get. The conveying member 6 has a ring shape, and the pair of upper and lower molding dies 1
The upper and lower sides are open so that 0 and 11 enter, a flange 6a extending outward is provided at the upper part of the outer peripheral surface, and the molten glass 5 or the glass material 8 is provided at the intermediate part of the inner peripheral surface. A ring-shaped step portion 6b for holding the inside of the inside 6 is formed.

Next, a description will be given of a molding method using the molding apparatus in the above-described embodiment in the case where a glass type BAL41 is used as the molten glass 5.

The nozzle 3 is held in the molding apparatus 100 and melted at 1000 ° C. in the glass melting furnace 1, and the molten glass 5 is transferred from the nozzle 3 maintained at the nozzle temperature of 740 ° C. to the transfer member 6 serving as a copper mold. To supply. The conveying member 6 is preheated to 630 ° C. by the preheaters 16 and 17. When the molten glass 5 is supplied into the conveying member 6, cooling air is blown from the cooling nozzle 7 while being supplied, the lower surface of the conveying member 6 is cooled to a glass transition point or lower, cut into a predetermined amount, and solidified. .
The glass material 8 in the conveying member 6 held in the solidified conveying member 6 is heated at 740 ° C. for 5 minutes from above and below by heaters 18, 19, 20, and 21 to form a shape by heating and softening. 13, a pair of molding dies 10, 11
The glass material 8 is press-formed by a pair of forming dies 10 and 11 which have been conveyed between the upper and lower openings of the conveying member 6. The mold temperature of press molding was performed near the transition point temperature (535 ° C.) of glass type BAL41. After the press molding, the optical glass element 14 is conveyed to an annealing furnace 15 to be gradually cooled and taken out.
I got

In the optical glass element formed by such a process, no defect was observed on the press-formed surface, and an optical glass element having extremely excellent optical performance could be obtained.

[0011]

Example 2 This example was used as a molten glass 5 with glass type BAH.
30 will be described.

The nozzle 3 is held in the molding apparatus 100 and melted at 1200 ° C. in the glass melting furnace 1, and the molten glass 5 is transferred from the nozzle 3 maintained at the nozzle temperature of 850 ° C. to the transfer member 6 serving as a barrel. To supply. The conveying member 6 is preheated to 630 ° C. by the preheaters 16 and 17. When the molten glass 5 is supplied into the conveying member 6, cooling air is blown from the cooling nozzle 7 while being supplied, the lower surface of the conveying member 6 is cooled to a glass transition point or lower, cut into a predetermined amount, and solidified. .
The solidified glass material 8 in the conveying member 6 is heated by the heater 1
After heating at 740 ° C. for 5 minutes from above and below by 8, 19, 20, 21 to form a shape by heat softening, the conveyor 1
At 3, the material is conveyed between the pair of molds 10 and 11 and press-molded. The mold temperature of press molding was performed near the transition point temperature (492 ° C.) of glass type BAH30. After press molding, the optical glass element 14 was conveyed to the annealing furnace 15 and gradually cooled and taken out to obtain the optical glass element 14.

The optical glass element molded by such a process did not show any defect on the press molded surface, and was able to obtain an optical glass element having extremely excellent optical performance.

[0014]

Embodiment 3 This embodiment uses glass type BAH as molten glass 5.
The case where the meniscus lens 30 is used and a meniscus lens is formed will be described with reference to FIG.

The nozzle 3 is held in the molding apparatus 100 and melted at 1200 ° C. in the glass melting furnace 1, and the molten glass 5 is transferred from the nozzle 3 maintained at the nozzle temperature of 850 ° C. to the transfer member 6 serving as a barrel. To supply. The conveying member 6 is preheated to 630 ° C. by the preheaters 16 and 17. When the molten glass 5 is supplied into the conveying member 6, cooling air is blown from the cooling nozzle 7 while being supplied, the lower surface of the conveying member 6 is cooled to a glass transition point or lower, cut into a predetermined amount, and solidified. .
The solidified glass material 8 in the conveying member 6 is heated by the heater 1
Heat at 760 ° C. from above and below for 8, 19, 20, 21 for 5 minutes. As shown in FIG. 2, the glass material 8 is deformed by its own weight due to heat softening, so that a concave portion is formed on the upper surface and a convex portion is formed on the lower surface. Then, it is conveyed between the pair of molds 10 and 11 by the conveyor 13 and press-formed. The mold temperature of press molding is the transition temperature of glass type BAH30 (492 ° C)
I went nearby. After press molding, the optical glass element 14 was obtained by being conveyed to an annealing furnace 15 and gradually cooled and taken out.

In the optical glass element formed by such a process, no defect was observed on the press-formed surface, and an extremely excellent optical performance could be obtained.

In the method for molding an optical glass element of the present invention, the conditions such as the composition of the optical glass, the conveying member, the temperature and time of the thermal deformation, and the shape of the optical glass molded body are the same as those of the above-described embodiments. However, the present invention is not limited to this.

[0018]

As described above, according to the method for molding an optical glass element of the present invention, the optical glass element can be molded in a non-contact manner by cooling and supplying the molten glass into the conveying member. It is possible to obtain a molded product free from defects due to clouding or the like, and it is possible to improve productivity and reduce costs.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a main part of a molding apparatus that performs a molding method according to embodiments 1, 2, and 3 of the present invention.

FIG. 2 is a diagram showing a state of self-weight deformation of a glass material in a forming step of a forming method according to a third embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 3 Nozzle 5 Molten glass 6 Inside transfer member 10 Mold 11 Mold 14 Optical glass element

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-5-254850 (JP, A) JP-A-5-170456 (JP, A) JP-A-4-357122 (JP, A) 60435 (JP, A) JP-A-3-12328 (JP, A) JP-A-4-280822 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C03B 11/00

Claims (3)

(57) [Claims] A step of supplying a predetermined amount of molten glass flowing out of a nozzle tip into the transport member from above the transport member and cooling and solidifying a lower side of the supplied molten glass; A method for molding an optical glass element, comprising: a step of heat-softening the glass material; and a step of press-molding the heat-softened glass material using a pair of upper and lower molds. A step of supplying a predetermined amount of the molten glass flowing out of the nozzle tip into the conveying member from above the conveying member, and cooling and solidifying a lower side of the supplied molten glass; An optical glass, wherein a desired optical glass element is formed by a step of heating and softening the glass material in the inside, and a step of press-forming the heated and softened glass material in a pair of upper and lower forming dies in a conveying member. Element forming method. 3. A step of supplying a predetermined amount of the molten glass flowing out of the nozzle tip into the conveying member from above the conveying member, and cooling and solidifying a lower side of the supplied molten glass; A step of forming a convex portion on the lower surface by heating and softening the glass material inside and deforming the glass material by its own weight, and a step of press-forming the heated and softened glass material with a pair of upper and lower forming dies in the conveying member, A method for forming an optical glass element, comprising forming an optical glass element.