JPH0712944B2 - Optical lens press molding equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a press molding apparatus for an optical lens by an induction heating method, and in particular, molding by uniformly heating a mold and a molding material. The present invention relates to a press molding device that is designed to improve accuracy.

(Prior Art) In recent years, as a method of molding an optical lens, a method of polishing finishing, which requires complicated steps, is applied, and a glass lump that has been weighed in advance by an induction heating method such as a high frequency wave is heated to be plasticized and precision pressed. The method of processing by is getting attention.

Conventionally, in this type of optical lens press molding apparatus, as illustrated in FIG. 3, an intermediate housing 3 is provided between the upper and lower housings 1 and 2, and inside the intermediate housing 3, the upper part is provided. A first hydraulic cylinder 6 extending from a first drive unit 5 in the housing 1 allows an upper press shaft 7 to freely move up and down to face an upper press shaft 7, and the upper press shaft 7 forms one mold. 8 is attached, while a second hydraulic cylinder 10 extending from a second drive unit 9 in the lower housing 2 faces a lower press shaft 11 which can be vertically moved up and down, and the lower press shaft 11 is attached to the other The lower mold 12 constituting the mold is attached, and a molding material (not shown) made of a pre-measured glass lump is placed between the upper and lower molds 8 and 12 to enable the mold to be clamped, and the molding chamber 4 To form a lifting mechanism around the upper and lower molds 8 and 12.
A glass tube 14 which can be raised and lowered by 13 is provided, and an induction heating coil 15 is wound around and fixed to the outside of the glass tube 14, whereby the upper and lower molds 8 and 12 are heated by induction.

However, in such a conventional structure, as shown in FIG. 4, the upper and lower molds 8 and 12 having the cavity portions 81 and 121 usually have a disc-shaped outer peripheral portion with a reference surface for centering. The present situation is to have four flat surface portions 8a and 12a including them, and to wind and fix a circular induction heating coil 15 around these outer peripheral portions with a gap.

(Problems to be solved by the invention) Therefore, in the above-mentioned conventional apparatus, the induction heating is performed between the flat surface portions 8a, 12a and the arc-shaped portions 8b, 12b of the outer peripheral portions of the upper and lower molds 8, 12. Since the distance to the inner circumference of the coil 15 is different, the temperature due to induction heating on the line passing through the centers of the molds 8 and 12 is 5th as shown in lines AA and BB in FIG.
As shown in the figure, the arc-shaped portion 8b near the induction heating coil 15,
The vicinity of 12b is high, while the flat parts 8a and 12a far from the induction heating coil 15 are low, and the temperature distribution of the molds 8 and 12 becomes non-uniform, which results in high temperature during lens molding. There is a problem in that the lens molding material tends to drip on the side of the arcuate portions 8b and 12b, which adversely affects the molding accuracy of an optical lens that requires precision processing.

The present invention has been made under the above circumstances, and an object thereof is to provide a press molding apparatus for an optical lens, which is capable of uniformly heating a mold and a lens molding material. It is in.

[Structure of the Invention] (Means for Solving Problems) In order to solve the problems described above, the present invention provides an induction heating coil on the outer periphery of a mold having a non-circular outer peripheral shape disposed in a molding chamber. In a press molding apparatus for an optical lens that is wound and heats and heats the mold by an induction heating means, a non-circular shape so that the gap between the inner circumference of the induction heating coil and the outer circumference of the mold is always constant. It is configured to be wound.

(Operation) That is, according to the present invention, with the above configuration,
Since the induction heating coil wound around the outer periphery of the mold is arranged so that there is always a certain distance according to the outer peripheral shape of the mold, the temperature distribution of the mold by induction heating is made uniform. This makes it possible to prevent uneven sagging of the lens molding material at the time of molding, so that a precise optical lens can be molded.

(Example) Hereinafter, the present invention will be described in detail with reference to an example shown in FIG. 1 and FIG. In the illustrated embodiment according to the present invention, the same parts as those of the conventional device shown in FIGS. 3 and 4 are designated by the same reference numerals, and the description thereof will be omitted.

That is, as shown in FIG. 1, the optical lens pressing device according to the present invention has four flat surface portions 8a, 12a and arc-shaped portions 8b, 12b including the centering reference surface on the disk-shaped outer peripheral portion. The induction heating coil 15 is wound and fixed according to the outer peripheral shapes of the upper and lower molds 8 and 12, and the space between the inner periphery of the induction heating coil 15 and the outer peripheries of the upper and lower molds 8 and 12 is constantly maintained. Constant gap L
With this configuration, the second
As shown in the figure, it is possible to heat and raise the temperature so that the temperature distributions of the upper and lower molds 8 and 12 are uniform by induction heating.

In addition, in the above-mentioned embodiment, the case where the cavity portions 81 and 121 formed in the upper and lower molds 8 and 12 are one is described as an example, but a plurality of cavity parts 81 and 121 are provided in one upper and lower molds 8 and 12. Even with a configuration in which the individual cavity portions 81 and 121 are array-molded to mold a plurality of lenses at one time, the operation and effect of the present invention can be sufficiently achieved.

In addition, it goes without saying that the present invention can be variously modified and implemented within the scope of the present invention.

[Effects of the Invention] As is apparent from the above description, according to the present invention, an induction heating coil is wound around the outer periphery of a mold having a non-circular outer peripheral shape disposed in a molding chamber, and the mold is induction-heated. In a press molding apparatus for an optical lens that heats and raises temperature by means, since the non-circular winding is performed so that the gap between the inner circumference of the induction heating coil and the outer circumference of the mold is always constant, Even if the outer peripheral shape of the mold is non-circular, the temperature distribution of the mold due to induction heating can be made uniform.
An optical lens having an excellent effect that a highly accurate optical lens can be molded because it is possible to surely prevent the uneven sagging of the lens molding material at the time of molding that occurs when a mold having a special shape is used. It is possible to provide the press molding apparatus of.

[Brief description of drawings]

FIG. 1 is a schematic plan view showing an embodiment of a state in which an induction heating coil is wound around a mold of a press molding apparatus for an optical lens according to the present invention, and FIG. FIG. 3 is an explanatory view showing a temperature state, FIG. 3 is a schematic explanatory view of a conventional optical lens press molding apparatus, and FIG. 4 is a schematic plan view showing a winding state of an induction heating coil around a mold, and FIG. Similarly, the figure is an explanatory view showing a heating temperature rising state by induction heating of the mold. 8, 12 ... Mold, 15 ... Induction heating coil, L ... Gap.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Koichi Iwata 3-2068 Ooka, Numazu City, Shizuoka Prefecture, Toshiba Machine Co., Ltd. Numazu Plant (72) Inventor Hisataka Sugiyama 3-2068 Ooka, Numazu City, Shizuoka Toshiba Machine Co., Ltd. Numazu Plant (72) Inventor Yoshizo Komiyama 2068 Ooka, Numazu City, Shizuoka Prefecture Numazu Plant, Toshiba Machine Co., Ltd. (72) Inventor Toshio Kaburagi 2-7-5 Nakaochiai, Shinjuku-ku, Tokyo Hoya Co., Ltd. (72) Inventor Shinji Hata 2-7-5 Nakaochiai, Shinjuku-ku, Tokyo Hoya Co., Ltd. (72) Inventor Hideki Komiya 2-7-5 Nakaochiai, Shinjuku-ku, Tokyo Hoya Co., Ltd.

Claims (1)

[Claims] 1. A press molding apparatus for an optical lens, wherein an induction heating coil is wound around an outer circumference of a mold having a non-circular outer shape arranged in a molding chamber, and the mold is heated and heated by an induction heating means. A press molding device for an optical lens, which is wound in a non-circular shape so that the gap between the inner circumference of the induction heating coil and the outer circumference of the mold is always constant.