JPH03284716A - Plastic-made progressive multi-focus spectacle lens and its production - Google Patents

Abstract

PURPOSE:To attain the massproduction of lenses having the same shape by forming each progressive multi-focus spectacle lenses consisting of transparent plastic by the injection molding or injection compression molding of plastic in an electroforming mold. CONSTITUTION:A master model having the same shape as spectacle lenses to be manufactured is formed at first. The model is formed by cutting and grinding a material such as a ceramic material containing glass, thermosetting plastic and precipitation hardening steel and finally polishing the product by expert's manual work. Then, conductive coating is applied to the surface of the master model 2, electrodes are connected to the model 2 and electroforming is executed by known method to form an electroforming layer 3 on the surface of the model 2. After demolding the layer 3 from the model 2, an electroforming layer is similarly formed also on the opposide side of the model 2. Consequently, the electroforming molds 4 for the shape of the model 2 are obtained, a thermoplastic plastic material is injected from an injection port 6 into the molding room 5 of the molds 4 by injection molding or injection compression molding and a molded product is taken outfrom the molds 4 to form the progressive multi-focus spectacle lens 1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a plastic progressive multifocal eyeglass lens and a method for manufacturing the same.

[Prior art and problems to be solved by the invention] Plastic lenses have become widely used as eyeglass lenses because they are lighter and more difficult to break than glass lenses, and are easier to mass produce than glass lenses. Particularly in recent years, plastic lenses have come to be used as special eyeglass lenses such as progressive multifocal lenses.

Conventionally, plastic progressive multifocal lenses have been manufactured by a casting method using thermosetting resin. In this method, thermosetting resin is injected between two molds made of glass plates that have the same curved surface shape as the surface of the lens to be manufactured, and after being heat-treated to polymerize and harden the thermosetting resin, Lenses are obtained by releasing the mold, but due to the shape, outer diameter, thickness, etc., it takes a long time of 7 to 36 hours for the thermosetting resin to harden, so it is not suitable for mass production and is expensive. There was also a problem. Furthermore, the molds made of glass plates used in the conventional casting method have the problem of being time-consuming to manufacture. Moreover, the surface precision of lenses obtained by casting using a mold made of glass plate is not very high (and for this reason, in some cases, the lens is manually polished after being released from the mold, but it is difficult to polish the lens by hand. In addition, in the case of lenses with complex shapes such as progressive multifocal lenses, it is extremely difficult to mass-produce lenses of the same shape by manual polishing.

The present invention has been made in view of the above-mentioned points, and an object of the present invention is to provide a plastic progressive multifocal eyeglass lens that solves the drawbacks of the above-mentioned prior art and a method for manufacturing the same.

[Means to solve the problem]

As a result of intensive research, the present inventor found that injection molding is particularly preferable because it causes less distortion of the lens, and by injection molding, he discovered a progressive multifocal lens and a method for manufacturing the same that can overcome the drawbacks of the above-mentioned prior art.

That is, the plastic progressive multifocal eyeglass lens of the present invention is
A progressive multifocal eyeglass lens made of transparent thermoplastic plastic, characterized in that the lens is formed by injection molding or injection compression molding the thermoplastic plastic in an electroforming mold. Further, the method for manufacturing a plastic progressive multifocal eyeglass lens of the present invention includes electroforming a master model for manufacturing a progressive multifocal eyeglass lens to form an electroformed layer on the surface of the master model, and then releasing the mold from the master model. A transparent thermoplastic is injection molded or injection compression molded into the molding chamber of an electroforming mold formed based on an electroformed layer.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 1 shows a schematic diagram (connecting parts of equal power with lines) of the power distribution of the cumulative multifocal eyeglass lens 1 of the present invention. Reference numeral 1 denotes a lens having a plurality of focal points depending on the distance from distance to near.

The spectacle lens 1 of the present invention is made of thermoplastic, and the raw thermoplastic is preferably transparent and has good optical properties. Examples of such thermoplastic include polymethyl methacrylate, polycarbonate, polystyrene, and polystyrene. Methylpentene and the like are preferred. Among these, polycarbonate is preferred because it has a high refractive index (and is difficult to break, making it easy to manufacture thin and large eyeglass lenses. Polycarbonate can also be colored by dyeing, making it easy to manufacture colored lenses such as sunglasses). In addition, polycarbonate lenses are preferable because they absorb ultraviolet rays and therefore serve to protect the eyes by blocking ultraviolet rays that are harmful to the eyes.

The spectacle lens 1- of the present invention is manufactured by injection molding or injection compression molding the thermoplastic plastic described above using an electroforming mold. The manufacturing method of the present invention will be explained below.

First, as shown in FIG. 2, a master model 2 having the same shape as the eyeglass lens to be manufactured is manufactured.

This master model 2 is made of ceramic materials including glass,
We perform cutting, grinding, and polishing using materials such as thermosetting plastics, precipitation hardening steel, which is generally used as mold material for injection molding of optical systems, stainless steel corrosion-resistant steel, and non-ferrous metals such as copper and brass. Finally, it can be manufactured by a method in which a skilled person performs manual polishing, or by using a dedicated machine such as a CNC aspheric surface processing machine.

Next, after applying a conductive paint to the surface of the master model 2, electrodes are connected and electroforming is performed based on a known method to form an electroformed layer 3 on the surface of the master model 2. FIG. 2 shows a case where the electroformed layer 3 is first formed only on one side of the master model 3. In this way, the electroformed layer 3 is formed only on one side of the master model 2. A method in which conductive paint is applied only to the areas where the electroformed layer is to be formed, a method in which only the areas where the electroformed layer is to be formed are immersed in the electroforming solution, and areas where the electroformed layer is not to be formed are covered with a sealant, etc. There are several methods, and electroforming may be performed using any of these methods or a suitable combination of these methods. After releasing the electroformed layer 3 from the master model 2, electroforming is performed on the opposite side of the master model 2 in the same manner. From the electroformed layer thus obtained, an electroformed mold 4 corresponding to the shape of the master model 2 is formed. can get(
Figure 3).

Note that the master model 2 is not limited to the case where electroforming is performed on each side of the master model 2 as shown in FIG. Although it is also possible to release the electroformed layer from the mold, it is preferable to obtain an electroformed layer on each side of the master model 2 because the electroformed layer can be easily released from the mold.

Further, the electroforming mold 4 can be manufactured by directly using the electroformed layer obtained by electroforming the master model 2, but it is also possible to manufacture the electroforming mold 4 by using the electroformed layer that has been released as a mold to create an electroforming master model and An electroformed mold may be manufactured using an electroformed layer obtained after repeating the steps once or about 2 to 10 times. Furthermore, the master model 2 does not have to be of the same shape as the lens to be manufactured as shown in the above example, but it is also possible to manufacture the electroforming mold 4 by using one of the opposite shape to the lens to be manufactured. You can also do it.

The progressive multifocal eyeglass lens of the present invention is formed by injection molding or injection compression molding thermoplastic plastic from the injection port 6 into the molding chamber 5 of the electroforming mold 4 obtained in this way, and then releasing the mold. 1 is obtained.

The time required for one molding cycle after injection molding or injection compression molding of thermoplastic plastics and releasing the mold after cooling is about 1 to 3 minutes.

〔Effect of the invention〕

As explained above, the progressive multifocal eyeglass lens of the present invention is manufactured by injection molding or injection compression molding thermoplastic plastic into an electroforming mold, so lenses of the same shape can be mass-produced and can be provided at low cost. It is something that Furthermore, since the mold used in the method of the present invention is manufactured using an electroformed layer formed by electroforming a master model, it is possible to easily and reliably obtain the desired shape even for complex shapes such as progressive multifocal lenses. Moreover, if one master model is made, it is easy to make molds of the same shape using that master model, so even molds with multiple molds can be manufactured easily. Since the method of the present invention is molded using thermoplastic, the molding cycle is shorter than that of thermosetting resin, and mass production can be easily achieved. Furthermore, the lenses obtained by the method of the present invention have high surface precision, and there is no need to polish the lenses after release as in the casting method, which has the effect of making it possible to manufacture excellent plastic lenses at low cost and efficiently.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a schematic diagram showing the power distribution of the progressive multifocal eyeglass lens of the present invention, and FIGS.
The figure is a schematic longitudinal cross-sectional view showing one step of the method of the invention. 1... Progressive multifocal eyeglass lens 2... Master model 3... Electroforming layer 4... Electroforming mold 5... Molding chamber 1 Progressive lens 1, eyedropper lens 2 Figure 3 Rust layer No. 3 Figure 5 Molding chamber

Claims (2)

[Claims] (1) A progressive multifocal eyeglass lens made of transparent thermoplastic, the lens being formed by injection molding or injection compression molding of the thermoplastic in an electroforming mold. focal eyeglass lenses. (2) After performing electroforming on a master model for manufacturing progressive multifocal eyeglass lenses to form an electroformed layer on the surface of the master model, molding an electroforming mold based on the electroformed layer released from the master model. A method for manufacturing a plastic progressive multifocal eyeglass lens, comprising injection molding or injection compression molding a transparent thermoplastic plastic indoors.