JPH0764568B2 - Glass gob and method and apparatus for manufacturing glass gob - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molding glass gob for molding a high precision optical glass element used in optical equipment by a glass molding method, a manufacturing method and a manufacturing apparatus therefor.

[0002]

2. Description of the Related Art A molding glass gob for molding a high precision optical glass element used in optical equipment by a glass molding method has a surface roughness as disclosed in, for example, Japanese Patent Publication No. 2-50059. There are pretty tight restrictions about. This is because even if the molding die is mirror-finished, the surface quality of the molded lens will be insufficient unless the glass gob has achieved a certain degree of surface roughness. is there.

The shape of the molding glass gob is also desired to be as close as possible to the final shape of the optical glass element. This is because the shape of the glass gob does not vary and is uniform, which is an essential condition for stabilizing the molding process and manufacturing a highly accurate optical element.

In order to obtain a glass gob having such a highly precise surface roughness and a uniform shape, the glass gob has conventionally been finished by polishing.

[0005]

As described above, conventionally, in the production of the glass gob used for forming the glass, the polishing process is required, which is a cost problem of the glass forming method.

Further, the glass gob sometimes contains an abrasive remaining in the polishing process, which may not be completely removed by normal washing. In this way, when the glass with the abrasive remaining therein is heated and pressed by a molding die to be molded, the molded lens obtained is not only a defective product,
The mold is fatally damaged, which causes the mold life to be shortened.

An object of the present invention is to provide a glass gob which can solve the above-mentioned drawbacks and which can be used for molding an ultra-precision optical element, and a method and an apparatus for manufacturing the glass gob.

[0008]

In order to solve the above problems, the present invention is to obtain a glass gob by receiving a molten glass by a glass member. Further, at this time, the glass member is moved relative to the dropped molten glass, if necessary.

[0009]

By receiving the molten glass on the glass member, the surface of the glass member is brought into close contact with the molten glass due to the amount of heat of the molten glass, and the two are integrated to form a glass gob. At this time, the surface of the molten glass that does not come into contact with the glass member is a free surface that comes into contact with air, and its shape is determined by the balance with the surface tension, but the surface roughness, defects, abrasives, etc. A good surface with no foreign matter attached.

Further, by moving the glass member relative to the molten glass to be dropped, the above free surface shape can be controlled, and a glass gob having a concave shape, a convex shape or the like can be obtained.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 is a plate-shaped glass member. Since the plate-shaped glass member 1 may have some waviness as long as it is a mirror surface, in this embodiment, it is processed into a flat plate by the stress cleaving method. Of course, it is also possible to use those processed by the conventional plane polishing method.

As shown in FIG. 1A, the plate-shaped glass member 1
The plate-shaped glass member 1 is installed below the nozzle 11 connected to the same type of glass melting furnace (not shown). When the temperature of the nozzle 11 is maintained at the optimum temperature by a heater (not shown), the molten glass 2 flows out from the nozzle 11 as shown in FIG. In this case, the weight of the molten glass 2 can be controlled to be constant by selecting the nozzle temperature and the nozzle size.

The molten glass 2 dropped on the plate-shaped glass member 1 melts the upper surface of the plate-shaped glass member 1 by the amount of heat and becomes integral with the plate-shaped glass member 1, and is free to come into contact with the air on the upper surface thereof. The surface 2a has a convex shape due to surface tension. After all, in this embodiment, the plano-convex glass gob 3 as shown in FIG.

The convex surface 2a thus obtained has a very good surface roughness. Further, the shape of the convex surface does not vary and is constant. Further, since the plate-shaped glass member 1 is formed by stress fracture, the lower surface 1a thereof also has a very good surface roughness. That is, 1a which is an optical function surface,
2a both have excellent surface roughness.

In the above embodiment, a plano-convex glass gob having a convex surface on one side was obtained. To obtain a bi-convex glass gob having a convex surface on both sides, the plano-convex glass gob 3 shown in FIG.
By doing so, a biconvex glass gob 4 as shown in FIG. 2 (c) can be obtained.

FIG. 3 showing another embodiment will be described.
By reducing the thickness of the plate-shaped glass member 1 or increasing the weight of the molten glass 2 as compared with FIG. 1, the amount of heat of the molten glass 2 is large and not only the surface of the plate-shaped glass member 1 but also the inside thereof, The lower surface is softened to obtain a biconvex glass gob 5 as shown in FIG. The convex surface thus obtained has a very good surface roughness. Further, the shape of the convex surface does not vary and is constant.

FIG. 4 showing still another embodiment will be described. The plate-shaped glass member 1 includes a plate-shaped glass member holder 21.
Placed on top. The plate-shaped glass member holder 21 is mounted on a plate-shaped glass member moving device 22 that is movable with respect to the nozzle 11 for molten glass. In this embodiment, the moving device 22 includes a shaft 23 that is separated from the nozzle 11 by a certain distance.
Is the center of rotation.

As shown in FIG. 4 (a), a plate-shaped glass member moving device 22 is installed below the nozzle 11 which communicates with a glass melting furnace (not shown) of the same kind as the plate-shaped glass member.
When the nozzle temperature is maintained at the optimum temperature by a heater (not shown), the molten glass 2 flows out from the nozzle 11. The outflow rate of the molten glass 2 can be controlled to be constant by selecting the nozzle temperature and the nozzle size.

As shown in FIG. 4B, the plate-shaped glass member moving device 22 is rotated around the shaft 23. The molten glass 2 flowing out onto the plate-shaped glass member 1 forms a convex surface, which is a free surface, on the outer peripheral portion of the plate-shaped glass member 1 due to surface tension, and the upper surface of the glass member 1 is melted by the amount of heat to melt the glass. It is integrated with the member 1. As a result, a glass gob having a convex outer peripheral portion as shown in FIG. 4C and a concave overall shape can be obtained.

As in the case of FIG. 3, by reducing the thickness of the plate-shaped glass member 1 or increasing the weight of the molten glass 2, the amount of heat of the molten glass 2 is large and only the surface of the plate-shaped glass member 1 is formed. Without softening the inside and the lower surface,
As shown in FIG. 4C, a biconcave glass gob 6 having a convex shape on the lower surface and a concave shape as a whole is obtained. Alternatively, as in the case of FIG. 2, the biconcave glass gob 6 can be obtained by reversing the plate-shaped glass member and performing the same process. The concave surface thus obtained has a very good surface roughness. Also,
The shape of the concave surface does not vary and is constant.

FIG. 5 showing another embodiment will be described.
1 to 4, the embodiments of the method for manufacturing the glass gob having the axially symmetrical shape are described. In FIG. 5, an example of a glass gob for forming an fθ lens will be described as a shape that is not axially symmetric.

Although not shown in FIG. 5, the plate-shaped glass member 1 is used as a plate-shaped glass member holder placed on a table movable with respect to the molten glass nozzle 11 as in FIG. It has been placed. The plate-shaped glass member 1 has a rectangular parallelepiped shape. As shown in FIG. 5A, a plate-shaped glass member moving device is installed below the nozzle 11 communicating with a glass melting furnace (not shown).

When the nozzle temperature is maintained at the optimum temperature by a heater (not shown), the molten glass 2 flows out from the nozzle 11. The outflow rate of the molten glass 2 can be controlled to be constant by selecting the nozzle temperature and the nozzle size. The plate-shaped glass member moving device linearly moves the plate-shaped glass member 1 in the direction of the arrow. The molten glass 2 flowing out onto the plate-shaped glass member 1 melts the surface of the upper surface of the plate-shaped glass member 1 by the amount of heat and becomes integral with the glass member 1, and the free surface of the upper surface in contact with air has surface tension. To give a convex shape.

If the speed of the linear movement of the plate-shaped glass member moving device in the direction of the arrow is controlled to be slow in the central portion of the plate-shaped glass member 1, the plate-shaped glass member 1 is made of molten glass 2.
A convex surface is formed on the top in the longitudinal direction. Figure 1
As in the case of the embodiment shown in (1), the plate-shaped glass member 1 is inverted and the molten glass is dropped on the opposite surface. In this case, if the speed of the linear movement of the plate-shaped glass member moving device in the direction of the arrow is controlled to be high in the central portion of the plate-shaped glass member 1,
A concave surface shape can be formed on the glass member 1 as shown in the drawing, and a long glass gob 7 having one convex surface and one concave surface can be obtained. Both surfaces obtained in this way have very good surface roughness. Also,
The shapes on both sides are constant without variation.

[0026]

As described above, according to the present invention, first, a plate-shaped member is made of a glass material, the member receives the same kind of molten glass, and a glass gob for molding having a smooth surface and a final shape is obtained. Since it uses a means, it does not require polishing for the production of glass gobs and is not only effective in reducing costs, but it can also finish the surface with good surface roughness free from foreign matter adhesion, and the mold due to foreign matter adhesion The life of the mold can be improved without scratching the surface.

[Brief description of drawings]

FIG. 1 (a) is a state diagram in which molten glass begins to drip from a nozzle in the first embodiment of the present invention. (B) is a state diagram in which a fixed amount of molten glass is dropped from a nozzle. (C) is the dropped molten glass and the plate-shaped glass member,
The state figure in which the plano-convex glass gob was formed.

FIG. 2 (a) is a state diagram in which molten glass begins to drip from a nozzle in the second embodiment of the present invention. (B) is a state diagram in which a fixed amount of molten glass is dropped from a nozzle. (C) is a drop of molten glass and a plano-convex glass gob,
The state figure in which the biconvex glass gob was formed.

FIG. 3 (a) is a state diagram in which molten glass has begun to be dropped from a nozzle in the third embodiment of the present invention. (B) is a state diagram in which a fixed amount of molten glass is dropped from a nozzle. (C) is the dropped molten glass and the plate-shaped glass member,
The state figure in which the biconvex glass gob was formed.

FIG. 4 (a) is a state diagram in which molten glass has begun to drip from the nozzle onto the outer peripheral portion of the plate-shaped glass member in the fourth embodiment of the present invention. (B) is a state diagram in which molten glass is continuously supplied to the outer peripheral portion of the plate-shaped glass member while rotating. (C) is the dropped molten glass and the plate-shaped glass member,
The state figure in which the biconcave glass gob was formed.

FIG. 5A is a diagram showing a state in which molten glass is supplied to one surface of a plate-shaped glass member in a longitudinal direction in a fifth embodiment of the present invention. (B) is a manufacturing state view of a glass gob which is concave in the longitudinal direction on the other surface of the plate-shaped glass member. (C) is a state diagram in which a glass gob having a convex shape on one side and a concave shape on one side and having an axially asymmetric shape is formed.

[Explanation of symbols]

 1 plate glass member 2 molten glass 3 plano-convex glass gob 4 biconvex glass gob 5 biconvex glass gob 6 biconcave glass gob 7 long glass gob 11 nozzle 21 plate glass member holder 22 plate glass member moving device

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tadataka Yonemoto 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Tadao Shioyama, 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd.

Claims (7)

[Claims] 1. A glass gob formed by supplying a glass glass member with the same kind of molten glass as that of the glass plate member. 2. A step of supplying a glass melt of the same kind as that of the glass plate member onto the glass plate member, and a step of integrating the glass plate member and the glass melt with the amount of heat of the glass melt. Glass gob manufacturing method. 3. The method for manufacturing a glass gob according to claim 2, wherein the plate-shaped glass member is manufactured by a stress cleaving method. 4. A step of supplying molten glass of the same type as that of the glass plate member onto the glass plate member, and a step of integrating the glass plate member and the glass melt with the amount of heat of the molten glass. A method for manufacturing a glass gob, which is carried out on both sides of the plate-shaped glass member. 5. The molten glass is supplied to the plate-shaped glass member while providing relative movement between the plate-shaped glass member and a nozzle for supplying the molten glass.
Method for producing the described glass gob 6. An apparatus for manufacturing a glass gob, comprising a means for holding a plate-shaped glass member and a means for supplying molten glass of the same kind as the plate-shaped glass member. 7. An apparatus for manufacturing a glass gob according to claim 6, wherein the means for holding the plate-shaped glass member is held and movable on a table movable with respect to the means for supplying molten glass of the same kind as the plate-shaped glass member.