JP2002348130A - Glass mold manufacturing method and mold used for it - Google Patents

Abstract

(57) [Summary] [Problem] It does not require prior processing of conventional crystallized glass,
Provided is a method of manufacturing a glass mold that can reduce time and cost even in the production of a replica mold for a concave lens, and a mold used therefor. A method for manufacturing a mold having a convex molding surface with a radius of curvature R used for molding a glass element or a plastic element having a concave surface by press molding, wherein at least the molding surface of the mold is covered. It is made of glass or crystallized glass having a softening point higher than that of the molded glass. The molded surface is formed into a convex surface having a radius of curvature r (where r <R), and the molded surface is formed into a convex surface having a radius of curvature R. . An air hole 5 is provided at the center of the concave surface, and the concave surface having the radius of curvature r and the air hole are connected by a smooth curved surface having a radius of curvature of 0.2 mm or more.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process for producing a glass mold for press-molding glass or plastic and a mold used therefor.

[0002]

2. Description of the Related Art In general, in molding an element such as a glass lens by press molding, a glass to be molded is placed in a molding die having a surface layer finished to a predetermined surface shape and then heated and softened, or heated and softened. The formed glass to be molded is put in, and a predetermined pressure is applied to the molding die, whereby the shape of the molding die is transferred to the glass to be molded to obtain a glass molded body. Therefore, the shape of the surface layer of the molding die is directly transferred as the surface shape of the glass molded body.

Conventionally, cemented carbides, ceramics, cermets, steels, and the like have been used as the base material used for the molds. However, it takes time and cost to precisely process them, and a large number of molds are required. Was difficult to manufacture in a short period of time.

[0004] In order to solve this problem, a glass before crystallization is crystallized after molding by a molding master using crystallized glass or the like for a molding die, and the glass mold (hereinafter, referred to as a glass mold) is used.
It is proposed to manufacture a replica mold).

[0005]

Problems to be solved by a conventional replica mold will be described with reference to FIGS. 3 (a) and 3 (b). FIG.
(A) and (b) are outlines of the steps of manufacturing a replica mold conventionally proposed. FIG. 3A is a schematic view of a state at the time of molding of a replica mold for convex lens molding that has been mainly proposed so far. A columnar crystallized glass (before crystallization) 2 is placed on a substrate 1 and heated, molded and crystallized while pressing a convex lens matrix 11 from above. At this time, the substrate 1 and the crystallized glass 2 are bonded by forming a film of Cr or the like on the contact surface of the substrate 1 with the crystallized glass 2. Through the above steps, the convex lens replica mold 12 is finished into a mold having a concave surface.

FIG. 3B is a schematic view showing a case where a replica mold for a concave lens is manufactured in the same process. Since the concave lens matrix 13 has a concave surface, when the columnar crystallized glass 2 is formed, an air pocket 15 is generated between the concave lens matrix 13 and the crystallized glass 2, and thus the concave lens matrix 13 is manufactured. A flat portion 16 is formed on the upper surface of the crystallized glass 2 in the concave lens replica mold 14, and the shape of the concave lens matrix 13 is not transferred to this portion.

In order to solve this problem, it is necessary to process the crystallized glass (before crystallization) into a spherical shape or a rocket shape. However, by imposing such a process, it is difficult to quickly and inexpensively produce the original replica mold.

According to the present invention, there is provided a method of manufacturing a glass mold which does not require the prior processing of the above-mentioned conventional crystallized glass and which can reduce time and cost even in the production of a replica mold for a concave lens, and a mold used therefor. The purpose is to provide.

[0009]

In order to achieve the above object, a method of manufacturing a glass mold according to the present invention is directed to a method of manufacturing a glass element or a plastic element having a concave surface by using a convex surface having a radius of curvature R used for press molding. A method for producing a mold having a molding surface, wherein at least the molding surface of the mold is made of glass or crystallized glass having a softening point higher than the glass to be molded, and the molding surface has a radius of curvature r.
(Where r <R), and the molding surface is formed into a convex surface having a radius of curvature R.

In the method of manufacturing a glass mold, it is preferable that the crystallized glass is formed into a convex surface having a radius of curvature R and then crystallized.

Next, the mold for manufacturing a glass mold according to the present invention comprises:
A mold for performing glass molding, at least a molding surface is made of glass or crystallized glass having a higher softening point than the glass to be molded, and to produce a mold having a convex molding surface with a radius of curvature R, Prior to this, a mold having a concave surface with a radius of curvature r for forming a molding surface into a convex surface with a radius of curvature r (where r <R), having an air hole at the center of the concave surface, The concave surface and the air hole are connected by a smooth curved surface having a radius of curvature of 0.2 mm or more.

In the mold for manufacturing a glass mold according to the present invention, it is preferable that an alloy containing Pt is formed as a protective film on the molding surface.

[0013]

According to a preferred embodiment of the present invention, in order to manufacture a replica mold for a concave lens having a desired radius of curvature R, the crystallized glass is first subjected to a radius of curvature r (r
<R), and as a second step, the radius of curvature R
And then crystallized. As a result, the replica mold for a concave lens can stably produce a large number of replica molds in a short time at low cost.

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2 (a) to 2 (d). FIG. 1 is a schematic view of a cross section of a molding die 10 according to the present invention. The substrate 20 is made of a cemented carbide, and the radius of curvature r of the molding surface 4 is smaller than the radius of curvature R of the target concave lens. An air hole 5 having a diameter of 0.7 mm is formed from the center of the molding surface 4.
The molding surface 4 and the air hole 5 are connected at a smooth surface having a radius of curvature C (C ≧ 0.2 mm). Further, a Pt-Ir alloy (2 μm
Thickness) is deposited. The composition ratio is Pt: Ir = 60:
40 (atomic%).

[0015] The mold used as Example 1 was R = 4 mm.
R = 3.5mm, C = 0.4m to make a concave lens
m.

Next, this step (shown in a schematic sectional view)
Will be described with reference to FIGS. All moldings were performed in a nitrogen flow. SK of high speed steel as base material 1
H4 was used. On the contact surface of the base material 1 with the crystallized glass 2, Cr was deposited in advance to a thickness of 0.1 μm.

First, as shown in FIG. 2 (a), a guide die 3 is set on a base material 1, a columnar crystallized glass 2 (before crystallization) is put therein, and further, a forming die 10 is put therein. Was. The crystallized glass used here is D150 manufactured by Matsunami Glass Industry Co., Ltd. The whole was heated to 550 ° C., the mold 10 was pressurized from above, held for 10 minutes, and then cooled.

Next, as shown in FIG. 2 (b), after cooling, the molding die 10 is removed, and as shown in FIG. 2 (c), a concave lens matrix 13 (R = 4 mm) is placed instead, and Pressurized. Here, the glass was crystallized by holding it at 550 ° C. for 10 minutes in a pressurized state, then heating it to 750 ° C. and holding it for 30 minutes. Then, after cooling gradually, the concave lens mother die 13 and the guide die 3 were removed as shown in FIG. As a result, a replica mold for a concave lens having a smooth curved surface with a radius of curvature of 4 mm was manufactured.

Next, as a comparative example, all of the molds 10 had a concave surface with a radius of curvature r = 3.5 mm and had no air holes.
A concave lens replica mold 17 was produced using the same mold as in FIG. This will be described with reference to FIGS. As shown in FIG.
Is set, and a columnar crystallized glass 2 is placed inside (before crystallization).
And a molding die 17 having no air hole. The whole was heated to 550 ° C., the mold 10 was pressurized from above, held for 10 minutes, and then cooled. Next, as shown in FIG. 4 (b), after cooling, the molding die 10 was removed and the shape was confirmed.
6 was confirmed. Next, as shown in FIG. 4 (c), a concave lens matrix 13 (R = 4 mm) was placed, and heating and pressurization were performed.
Here, the glass was crystallized by holding it at 550 ° C. for 10 minutes under pressure and then heating to 750 ° C. and holding it for 30 minutes.

Thereafter, after gradually cooling, as shown in FIG. 4D, the concave lens matrix 13 and the guide mold 3 were removed, and a concave lens replica mold 18 was manufactured. This replica mold 18
Was used as a comparative example.

In the replica mold 18 of the comparative example, a minute flat portion 19 was still left, although a little. FIG.
The part corresponding to the outer peripheral part of the flat part 16 confirmed in (b) is
Also in the final replica mold 18, the minute projections 22 that inhibit the smoothness of the curved surface were formed.

As described above, when the mold having no air hole 5 is used, the shape of the concave lens matrix 13 is not completely transferred while leaving the flat portion 19 to the end although it is minute. 4 (b), the outer periphery of the flat portion 16 remained as the projection defect 22.

Here, a cemented carbide as the base material 20 and a steel speed steel as the base material 1 may be used, even if cermet, ceramics, crystallized glass, glass having a softening point higher than the glass to be formed, or the like is used. Good.

Although crystallized glass is used for the replica mold, a glass material having a higher softening point than the glass to be molded may be used.

In the molding die 10 shown in FIG. 1, C is set to 0.4 mm in the embodiment.
It is known that if the value of C is less than 0.2 mm, the constriction at the tip of the crystallized glass 2 in FIG. 2B becomes sharp and remains as a defect even after being molded by the concave lens matrix 13.

In this embodiment, the air holes are formed from the molding surface.
Although it penetrated to the back of the mold, as long as it does not adversely affect the shape of the crystallized glass, it may be closed halfway without penetrating.

[0027]

As is apparent from the above description, if the glass mold is manufactured according to the process of the present invention using the mold for manufacturing the glass mold of the present invention, it is necessary to process the crystallized glass in advance. Thus, a large number of glass molds can be easily produced advantageously both in terms of time and cost.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a mold according to one embodiment of the present invention.

FIGS. 2A to 2D are schematic cross-sectional views illustrating a molding process of a glass mold according to one embodiment of the present invention.

FIG. 3 is a schematic cross-sectional view of a state during molding of a conventional glass mold.

FIGS. 4A to 4D are schematic cross-sectional views illustrating a molding process of a glass mold of a comparative example.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 base material 2 crystallized glass 3 guide mold 4 molding surface 5 air hole 10 molding die 11 master mold for convex lens 12 replica mold for convex lens 13 mother mold for concave lens 14 replica mold for concave lens 15 air pocket 16 flat part 17 air hole Mold without mold 18 Replica mold for concave lens 19 Micro flat part 20 Base material (high-speed steel) 21 Protective film 22 Micro protrusion defect

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // B29L 31:00 B29L 31:00 (72) Inventor Miyoko Toi 1006 Kazuma, Kazuma, Kadoma, Osaka Matsushita Electric Within Sangyo Co., Ltd. (72) Inventor Shoji Nakamura 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. F term (reference) 4F202 AF16 AJ06 CA09 CB01

Claims (4)

[Claims] 1. A method for producing a mold having a convex molding surface with a radius of curvature R used for molding a glass element or a plastic element having a concave surface by press molding, wherein at least the molding surface of the mold is formed. It is made of glass or crystallized glass having a higher softening point than the glass to be formed, and the forming surface is formed into a convex surface having a radius of curvature r (where r <R), and the forming surface is further formed into a convex surface having a radius of curvature R. A method for manufacturing a glass mold. 2. A molding surface of the crystallized glass is defined by a radius of curvature R.
The method for producing a glass mold according to claim 1, wherein the glass mold is crystallized after being formed into a convex surface. 3. A mold for glass molding, wherein at least the molding surface is made of glass or crystallized glass having a softening point higher than that of the glass to be molded, and has a convex molding surface with a radius of curvature R. A mold having a concave surface with a radius of curvature r for forming a molding surface into a convex surface with a radius of curvature r (where r <R) prior to manufacturing, comprising an air hole at the center of the concave surface; A mold for manufacturing a glass mold, wherein the concave surface having the radius of curvature r and the air hole are connected by a smooth curved surface having a radius of curvature of 0.2 mm or more. 4. The mold for manufacturing a glass mold according to claim 3, wherein an alloy containing Pt is formed as a protective film on the molding surface.