JP2811793B2 - Precision optical glass forming equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a precision optical glass molding apparatus for molding precision optical glass such as an optical glass lens.

[Prior Art] In recent years, in addition to the conventional grinding and polishing methods, optical glass lenses have been directly press-molded with a molten optical glass using a mold, and optical glass materials have been preliminarily approximated to the final shape. A method of press-molding a preform optical glass material using a molding die has been used.

Among the above-described methods, a method of manufacturing by press molding from the viewpoint of labor-saving production and automation is regarded as a promising method for producing an optical lens in the future. In particular, a method of press-molding a preform optical glass material is most promising because it is excellent in terms of temperature control and the like, and an apparatus for performing this method has been developed and put into practical use.

Here, as described above, as an apparatus for press-molding an optical glass lens using a preform optical glass material, an upper and lower platen, and a lower mold and an upper mold interposed between these platens are used. The optical glass material is heated to a predetermined temperature while the optical glass material to be molded is placed on the lower mold, and the molding die is inserted between the upper and lower platens. The optical glass material is press-formed by applying a pressing force using an upper mold.

[Problems to be Solved by the Invention] By the way, in the above-mentioned forming die constituting the press working apparatus according to the prior art, the upper surface of the upper mold is placed with the optical glass material to be formed placed on the lower die. Is in contact with this optical glass material, so if, for example, the mold surface of the upper mold has a convex shape, the load on the upper mold will cause dents on the surface of the optical glass molded product, or There is a disadvantage that the releasability of the upper mold after completion is poor, and the life of the mold is significantly shortened.

The present invention has been made in view of the above points, and an object of the present invention is to provide a precision optical glass molding apparatus capable of forming an optical glass molded article free from dents and the like during molding. Is to provide.

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention provides an upper die in a body die provided with a lower die so as to be movable in a direction approaching / separating from the lower die. The mold is inserted between the upper and lower platens, and the optical glass material to be molded placed on the lower mold is pressed by pressing under heat at the position between both platens. An apparatus for molding, the upper mold holding between the upper mold and the body mold for urging and holding the mold surface of the upper mold separated from the surface of the optical glass material to be molded. It is characterized by having a configuration including means.

[Operation] By adopting such a configuration, when the optical glass material to be molded is set on the lower mold of the mold composed of the body mold, the lower mold and the upper mold, the upper mold is held by the upper mold holding means. The upper mold can be kept separated from the optical glass material to be molded.In this state, the optical glass material is inserted between the upper and lower platens, the optical glass material is heated to a predetermined temperature, and then applied between the platens. Since the optical glass material is formed by applying pressure to press the optical glass material by the upper mold, press molding can be performed without causing dents or the like on the molded product. Further, after the molding is completed, the upper mold can be separated from the molded product by the upper mold holding means, so that the releasability can be improved and the life of the mold can be prolonged.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

The drawing is a cross-sectional view of an essential part showing an embodiment of a precision optical glass forming apparatus, in which 1 indicates a platen, 2 indicates a lower platen, and a mold is inserted on the lower platen 2. Has become. The molding die surrounds the lower die 3 and the lower die 3, and is provided with a cylindrical trunk die 4 extending above the upper surface 3 a of the lower die 3. The mold 5 is provided so as to be able to move up and down, and the upper mold 5 is configured to be lowered by the pressing force of the upper platen 1. Such a structure is well known in this type of molding apparatus.

However, this embodiment is characterized in that the upper die 5 is provided with a flange portion 5a, and the flange portion 5a and the upper surface of the body die 4 are provided.
4a in that a spring 6 as upper mold holding means is elastically mounted. The spring 6 is formed of a member having good heat resistance such as ceramics. When the preform optical glass material 7 is placed on the upper surface 3a of the lower mold 3 by the spring 6, the mold surface of the upper mold 5 is formed. 5b is the upper surface 7a of the glass material 7
From a predetermined distance. Here, since the upper die 5 moves up and down, it goes without saying that the spring 6 is formed so as not to obstruct the movement of the spring 6 to the stroke end of the lowering operation of the upper die 5. .

In this embodiment, the upper mold 5 is pushed upward by the action of the spring 6 and the preform optical glass material 7 is moved downward by the action of the spring 6 as shown in the drawing.
Is placed on the upper surface 3a. As a result, the upper surface 7a of the optical glass material 7 is kept separated from the mold surface 5b of the upper mold 5. This is inserted between the upper and lower platens 1 and 2, and the optical glass material 7 is heated to a predetermined temperature to be softened. In this state, a pressing force is applied to the upper die 5 by the upper platen 1 to The press molding of the optical glass material 7 is performed by lowering the mold 5 against the spring 6.

As described above, the mold surface 5a of the upper mold 5 is kept in a non-contact state with the upper surface 7a of the optical glass material 7 until the optical glass material 7 is heated and actually pressed. By doing so, there is no possibility that a dent is generated during press molding. When the optical glass material 7 is heated, the spring 6 is also heated at the same time. However, since the spring 6 is made of a member having good heat resistance, it is inconvenient to be deformed or deteriorated. Does not occur.

After the molding is completed as described above, the upper platen 1
The pressing force on the upper mold 5 by the above is released. This allows
The upper mold 5 is displaced in a direction in which the mold surface 5b is separated from the molded product by the action of the spring 6, and the release of the upper mold 5 from the molded product is promoted. If the upper mold 5 has good releasability as described above, the upper mold 5 is protected and the life thereof can be extended.

In the above-described embodiment, the lower mold 3 is formed separately from the body mold 4, but the lower mold and the body mold may be integrally formed.

[Effects of the Invention] As described above, according to the present invention, since the upper mold constituting the molding die is configured to be held away from the upper surface of the preform optical glass material by the upper mold holding means, There are various effects such as no dents formed on the optical glass at the time of press molding, good mold release properties after completion of press molding, and extension of the life of the mold.

[Brief description of the drawings]

The drawing is an explanatory diagram of a main part configuration showing one embodiment of the present invention. 1: Upper platen, 2: Lower platen, 3: Lower mold, 4: Body mold, 5: Upper mold, 6: Spring, 7: Preform optical glass material.

Claims (1)

(57) [Claims] An upper mold is provided in a body mold provided with a lower mold, and a mold is provided so as to be movable in a direction approaching / separating from the lower mold. An apparatus for press-molding an optical glass material placed on a lower mold by applying pressure under heating at a position between the two platens, wherein an apparatus is provided between the upper mold and the barrel mold. The apparatus for forming precision optical glass according to claim 1, further comprising an upper mold holding means for urging and holding a mold surface of said upper mold in a state of being separated from a surface of said optical glass material to be molded.