JPH02199035A - Molding of optical part - Google Patents

Abstract

PURPOSE:To suppress reaction between a material to be processed and a molding face of mold for molding and to prevent change of color and surface roughness of molded optical parts in molding glass and plastic by direct press molding, by adopting specific constitution in material of mold for molding and atmosphere during molding process. CONSTITUTION:In molding optical parts by placing a material to be processed made of glass or plastic on a molding face of mold for precision molding having the molding face and press molding the material, the following constitution is adopted. Namely, at least the molding face of the mold for precision molding is made of a hard layer or hard substance consisting essentially of a compound containing chromium and oxygen and at least press molding process among molding process is carried out in an oxidizing atmosphere.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention is applicable to optical measuring instruments such as cameras, microscopes, and telescopes;
Video equipment such as video cameras, video movies, video discs, FS 'ff I such as compact discs, etc.
The present invention relates to a method of molding optical parts such as glass lenses and plastic lenses used as L in optical equipment such as office equipment such as A-type machines, facsimile machines, laser beam printers, and copying machines.

(Prior art) Recently, glass lenses and plastic lenses for optical equipment can be made with no aberration at 1it-.Therefore, there is a tendency for aspherical lenses to have an L power (L power).When manufacturing this aspherical lens, conventional The 9'-polishing method, which is a manufacturing method for optical lenses, is performed using a direct press molding method due to its additivity and difficulty in mass production.

When molding a 9'7 part using the 11゛1-contact press molding method, the workpiece material made of glass or plastic is placed on the molding surface of a precision mold mold and pressure molded while being heated at an elevated temperature, or In this method, a heated workpiece material is placed on a molding surface and pressure-molded, thereby molding an optical component with an area that is a copy of the molding surface. In this case, the molding surface of the precision molded mold, which initially has an excellent surface F + 1 degree, becomes rough due to the influence of the atmosphere during pressure molding or reaction with the material to be added, especially when the material to be processed is glass. There is a problem that the temperature during pressure molding is high and it becomes impossible to put it into practical use in a short period of time. Representative examples of attempts to solve these problems include JP-A-62-3030 and JP-A-61-5.
There is a publication No. 0334.

(Problems to be Solved by the Invention) Japanese Patent Application Laid-Open No. 62-3030 discloses that a precision molding tool route in which a coating film of silicon carbide is formed on the surface of a cemented carbide is used in an inert gas atmosphere. Alternatively, a method for forming an optical glass element is disclosed in which the glass to be formed is heated to a temperature below its softening temperature in a vacuum and then pressure formed. This publication states that the thermal expansion coefficients of the cemented carbide, which is subject to a high f+"1 degree shape load, and the coating film of silicon carbide formed on the surface of this cemented carbide are well matched, and as a result, the The adhesion between the cemented carbide and the film is excellent even when the mold is heated, press-formed, and cooled during the press-molding process of glass, which is a processing material. ?Formation of Glass ElementsAlthough it is disclosed that 117 people are involved in the process, a reaction occurs between the heat-softened glass and the silicon carbide film, and the reaction is significant especially in an oxidizing atmosphere, resulting in a rough film. There are also problems such as discoloration of the pressure-molded glass and generation of bubbles in the glass.

JP-A No. 62-50334 discloses a method of forming a metal nitride layer on the surface of a cemented carbide. A mold for forming glass elements is disclosed. The invention disclosed in the same publication does not have direct contact between the cemented carbide and the glass, so compared to the conventional molding route made of steel or cemented carbide, there is less reactivity with the glass that has been softened by heating. Although there is little damage to the drying route, there are problems such as discoloration of the pressure-formed glass and the formation of air bubbles in the glass.

The present invention solves the above-mentioned problems, and specifically, uses a precision molding tool route that has extremely low reactivity with plastics and glass at high temperatures, and in an atmosphere with the lowest reactivity. The object of the present invention is to provide a method for molding optical components by pressure molding.

(Pth stage for solving the problem) The present inventors 1. When molding lenses for optical equipment, especially glass lenses that need to be pressure molded at high temperatures, by direct press molding, conventional precision molding In response to the problem that it cannot be put into practical use due to the high reactivity between the child root and glass,
This problem was proposed and solved in Japanese Patent Application No. 176535/1983. Based on the precision molding mold proposed in Japanese Patent Application No. 63-176535, the present invention was completed by studying the optimum conditions for practical use.

In other words, the light of the present invention'? The method for forming parts is to place a workpiece material made of glass or plastic into the mold of a precision molding mold, and then through a pressure molding process, to form a part from the applied material. A method,
At least the molding surface of the precision molding mold is made of a hard layer or hard body containing a compound containing chromium and oxygen.

The method is characterized in that at least the pressure molding step of the molding step is performed in an oxidizing atmosphere.

The light of the present invention'? Specifically, precision molding molds used in parts molding methods are those with a small molding element route (both molding surfaces are chromium The first composite mold consists of a hard layer consisting of a FrI film or a thermal sprayed layer containing a compound containing chromium and oxygen as one component, or at least the molding surface of the molding element route made of the above base material is made of chromium and acid. The second composite mold is made up of a hard body made of a sintered body whose L component is a compound containing chromium and oxygen, or the entire molded mold is composed of a sintered body whose L component is a compound containing chromium and oxygen. I can mention the Koshi route.

Among these fI11 dense molding drying routes, the first composite molding is made of the following base material, at least the molding surface of which is formed by the conventional chemical vapor deposition method (CVD method),
A compound containing at least one chromium and oxygen selected from chromium oxide, l'il chromium carbide, chromium oxynitride, or oxidized chromium nitride formed by physical vapor deposition (PVD) or thermal spraying, or this compound It consists of a hard layer consisting of a coating film or a welding layer containing 50% by volume or more.

In addition, the second composite mold is a base material described in 1 above, in which at least the molding surface of the molding element root contains at least l rare chromium and oxygen among chromium oxide, chromium oxide, chromium oxynitride, or chromium oxynitride. A hard body made of a sintered body of a compound,
or oxides and carbides of metals of groups 4a, 5a, and 6a of the periodic table excluding Cr in addition to 50% by volume of this compound;
Nitride, boride, Sl.

8 oxides, nitrides, carbides, Ail oxides, nitrides, alkaline earth metals ([1B, ldg, Ca
, Sr, Bal oxides, rare-L metals (Sc, Y
, La, Ce, Pr, Nd.

Ss, Eu, Gd, Tb, 01.1-1o,
oxides of Er, Tn+, Yb, Lu) and their phase solid solutions, or N6. Ta.

Cr Ill, Ru, Rh, Pd,
Re, Ir, pt, Lu, Fe,
Ni.

It is made of a hard body made of a sintered body containing at least IN in Co. The molding surface of this second composite mold is, for example, a molding surface portion formed by molding with a thickness of several III, and its outer peripheral portion and lower surface portion are formed by molding with a thickness of, for example, several III. It can be produced using the base material described in ゛. At this time, if the base material is steel or copper alloy, the forming surface and the base material can be combined using the conventional shrink fitting method, brazing method, or metallization method. When the base material is made of a sintered body such as cemented carbide or ceramics, a composite mold can be obtained by brazing or metallizing.

The molding surface described here is the mold surface where the 1° material to be applied and the precision molding element root come into direct contact during pressure molding when the material to be applied is molded into the desired shape. be.

In the molding method for 9'r parts of Kippatsu 1!1, at least the pressure forming stage is in an oxidizing atmosphere, which means that the material to be applied is heated and softened, and the molding surface of the precision molding element route is heated and softened.
1. Pressure forming process or this pressure forming process. This means that the first stage of production, including the second stage and the other stage 1, is in an oxidizing atmosphere. Among these, oxidizing atmosphere is
Specifically, 1. For example, in the atmosphere, reduced pressure in the presence of oxygen gas,
A gas atmosphere consisting of a mixed gas of N2 or an inert gas and oxygen gas, or a mixture of compounds containing oxygen elements such as Co, Co2, etc. in place of oxygen gas.

In particular, an oxidizing atmosphere is a gas atmosphere in which at least one of oxygen or a compound containing an oxygen element is present. This is preferable because the reactivity between the processing material and the molding surface of the precision mold mold is significantly reduced.The conversion to oxygen partial pressure described here is as follows: 191.For example, in 1110 steam of I Torr, the oxygen partial pressure is 0.5To
rr and CO of l Torr.

In this case, the oxygen partial pressure is assumed to be I Torr.

(Function) In the optical component molding method of the present invention, the molding surface of the precision molding tool route that directly contacts the material to be molded into the optical component contains a compound containing chromium and oxygen. Since it is made of a hard layer or a hard body, it has the effect of severely suppressing the reactivity between the material to be applied and the molding surface. In addition, the method for molding an optical component of the present invention uses a precision mold mold having a molding surface whose L component is a compound containing chromium and oxygen, from the material to be added. During the oxidizing atmosphere during the t1 forming step for producing parts, the oxygen in the atmosphere acts to further suppress the reaction between the heated workpiece material and the molding surface. be.

(Example) Example 1 90wL%CrJx I Ow1%ZrL sintered body.
13x l:3x with mirror polished surface 4. fl++
Molded to m size and polished to this mirror surface 6Jl 7φX3mm
A commercially available lead glass of the same size was installed and held at 650°C for 15 minutes in various atmospheres as shown in Table 1, and the specular state of the sintered body and discoloration of the lead glass were examined and are also listed in Table 1. did.

For comparison, commercially available A°C 203-based sintered bodies, SiC-based sintered bodies, and IC-Co-based sintered bodies were used in the same manner as the F2 method to determine the mirror state of each sintered body and the discolored state of lead glass. were investigated and listed in Table 1.

Example 2: Using die steel as material, precision molding molds with molding surfaces made of the sintered body used in Example 1 were prepared, and lead glass molds were made using each precision molding mold under the following conditions. A convex lens was molded, and the results are shown in Table 2.

Molding conditions Mold shape 10φ Margin (Effect of the Invention) The method for molding an optical component of the present invention is 1 Comparative molding method that deviates from the method of the present invention (Comparative method 1 of Example 1, 2.3.4)
and Comparative Method 20 of Example 2), compared to conventional molding methods (Comparative Methods 5 to 19 of Example 1 and Comparative Methods 21 to 29 of Example 2), the relationship between the molding surface and the workpiece material is It has the following effects: very little reaction, very little adhesion of the pressurized material to the molding surface, and almost no discoloration or surface roughness of the applied material after molding.

Patent applicant: Toshiba Tungaloy Corporation

Claims (2)

[Claims] (1) In a method of molding an optical component from the workpiece material by placing a workpiece material made of glass or plastic on the molding surface of a precision molding mold having a molding surface and performing a pressure molding process, the precision molding An optical device characterized in that at least the molding surface of the mold is made of a hard layer or hard body mainly composed of a compound containing chromium and oxygen, and at least the pressure molding step of the molding process is performed in an oxidizing atmosphere. How to form parts. (2) The oxidizing atmosphere is a gas atmosphere in which at least one of oxygen or a compound containing an oxidizing element is present, and the vapor pressure of the gas atmosphere is 10^- in terms of oxygen partial pressure. 2. The method for molding an optical component according to claim 1, wherein the pressure is ^2 Torr or more.