JPH11147725A - Mold for press forming and glass formed product by the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a mold having extremely smooth surface nature, high- precision accurate shape and slight deterioration, by forming a thin film-like protecting film on a press forming face of a mold parent material composed of an oxide through a substrate layer comprising one or more metals of Ti, V, Cr, Zr, Nb, Mo, Hf, Ta and W or an alloy. SOLUTION: A parent material composed of glass or single crystal alumina having a smooth surface, a parent material composed of glass or single crystal alumina having formed a fine pattern corresponding to a glass product, a parent material composed of glass or single crystal alumina having a formed shape corresponding to an optical glass element, etc., are preferable instead of a mold parent material made of an oxide. The smoothness of the press forming face of each parent material is properly <=5 nm, preferably <=2 nm, more preferably <=1 nm for a magnetic disc and is obtained by polishing using fine particles of cerium oxide.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a press molding die for producing a glass substrate for a magnetic disk most suitable for a recording medium such as a magnetic disk in a large amount at low cost, a method for manufacturing the same, and a method for manufacturing a glass substrate for a magnetic disk. Also, the present invention relates to a press-molding die for producing high-precision optical glass elements such as optical lenses in large quantities at low cost, a method for producing the same, and a method for producing an optical glass element.

[0002]

2. Description of the Related Art In recent years, in the field of magnetic recording, in particular, in magnetic disks, high performance such as miniaturization, thinning, and high capacity has been advanced. Glass substrates with high rigidity, high hardness and easy smoothing have been actively studied because they are extremely advantageous for high density and high reliability.

Conventionally, a glass substrate for a magnetic disk has been cut out to a predetermined size and then cut out to obtain a smooth surface.
It has been manufactured by a polishing method of polishing a glass substrate one by one. However, there are drawbacks that high precision is required for the polishing step and that the number of steps is large.

[0004] On the other hand, a number of studies have been made on a press molding method capable of high quality and high productivity in the field of optical glass element production, and practical use has already been achieved.

By the way, a mold used for press molding requires a special mold which does not deteriorate even if glass is repeatedly molded, and various studies have been made.

[0006] As a press-forming mold base material, a cemented carbide (tungsten carbide), cermet, zirconia, silicon carbide or other ceramics is used. The mold protects the base material and prevents adhesion of glass at the time of mold release. For this reason, a coating with a protective film having good releasability, oxidation resistance, and reaction resistance has been developed.

For example, Japanese Patent Application Laid-Open No. 2-137914 proposes a molding die in which a noble metal alloy thin film is provided on the surface of a cemented carbide and a fine pattern is formed on the surface of the alloy. However, cemented carbide (tungsten carbide) and cermet used as a base material have poor workability, and have sufficient smoothness (nm) as a mold for a magnetic disk substrate.
It is difficult to obtain a smoothness on the order), and there is a problem that defects are easily generated on the surface during processing.

Further, the noble metal alloy thin film has defects that it is very difficult to perform fine processing, it is difficult to obtain a desired pattern, and the quality of the obtained magnetic disk substrate is inferior.

Further, in optical elements such as optical lenses and prisms, minute irregularities on the surface of the mold lead to an increase in scattered light, and a lens having better surface smoothness is required. Then we were at the limit.

Japanese Patent Application Laid-Open No. 1-148714 discloses a technique for using a glass material, which can easily obtain sufficient smoothness as a magnetic disk substrate, as a molding base material. Attempts have been made to produce and use a protective film made of ceramics or a noble metal material as a material, and according to JP-A-64-33022, a fluoride such as MgF ₂ or an oxide such as SiO ₂ is released from the mold. It has been proposed as an optical element molding die used as a coating. Also, in the description of Japanese Patent Application Laid-Open No. 2-51434, glass is used as a base material for press molding, has a thin film in which a fine pattern is formed on the surface by fine processing, and is formed through an intermediate film made of silicon carbide and silicon nitride. A molding die on which a carbon film is formed as a protective film has been proposed as an optical disk molding die.

[0011]

However, none of them have sufficient durability against repeated use under severe high temperature and pressure in press molding, and roughened press surfaces due to repeated use for a long period of time. In some cases, the surface roughness may be increased, and the micro-protective film may be peeled off. The quality of the product, such as the deformation of fine patterns, may be degraded. There was a problem that there is no.

Conventionally, a die has been processed by a grinding method in which a disk-shaped diamond grindstone is rotated to perform processing. However, a disk-shaped diamond grindstone having a diameter of 2 mm or less is currently manufactured. Therefore, it was not possible to process a mold having a concave shape having a diameter less than this diameter, and there was a limit to the production of an optical glass element by a press molding method.

Accordingly, an object of the present invention is to solve the above-mentioned drawbacks of the prior art, and to provide an ultra-smooth surface and a high-precision precise shape corresponding to a magnetic disk substrate and an optical glass element to be manufactured. It is possible to manufacture a glass substrate for a magnetic disk and an optical glass element in which the shape of a mold is precisely and highly accurately transferred in press molding, and a magnetic disk substrate with less mold deterioration even when used repeatedly for a long time. The present invention also provides a mold for pressing an optical glass element and a method for manufacturing the same, and a glass substrate for a magnetic disk and an optical glass element manufactured using the same.

Another object of the present invention is to provide a press die for an optical glass element having a convex shape having a diameter of 2 mm or less, which cannot be produced by the conventional press molding method, a method for producing the same, and an optical glass element. .

[0015]

According to a first aspect of the present invention, there is provided a precious metal-based material formed on a press-formed surface of a metal mold base material via an underlayer made of a heat-resistant metal or alloy. This is a press-molding die on which a thin-film protective film made of the above metal or alloy is formed.

According to a second aspect of the present invention, a precious metal-based metal or alloy is formed on a pressed surface of a press-forming base material made of glass or single-crystal alumina with a smooth surface through an underlayer made of a heat-resistant metal or alloy. This is a press molding die on which a thin protective film is formed.

According to a third aspect of the present invention, a press-formed surface of a base material of a molding die made of glass or single-crystal alumina formed with a fine pattern corresponding to a glass product is provided via a base layer made of a heat-resistant metal or alloy. And a press-forming die on which a thin protective film made of a noble metal-based metal or an alloy thereof is formed.

According to a fourth aspect of the present invention, a press-formed surface of a base material of a molding die made of glass or single-crystal alumina having a shape corresponding to an optical glass element is provided via an underlayer made of a heat-resistant metal or alloy. And a press-forming mold on which a thin protective film made of a noble metal or an alloy thereof is formed.

According to a fifth aspect of the present invention, a base layer made of a heat-resistant metal or an alloy is formed on at least a press-formed surface of a base material of a forming die formed by dry etching glass or single-crystal alumina having a smooth surface. And a dry-etching of the surface of the underlayer, followed by forming a thin protective film made of a noble metal or alloy by a sputtering method.

According to a sixth aspect of the present invention, there is provided a method for forming a fine pattern corresponding to a glass product on a glass or a single crystal alumina having a smooth surface by dry etching. After forming a base layer made of a conductive metal or alloy by a sputtering method and dry-etching the surface of the base layer, a thin-film protective film made of a noble metal-based metal or alloy is formed by press-forming metal formed by a sputtering method. Type.

According to a seventh aspect of the present invention, a heat-resistant metal or alloy is formed on a press-formed surface of a base material of a molding die formed by dry-etching a surface of glass press-formed by a molding die having a glass product shape. A press-forming mold in which a base layer made of a metal is formed by sputtering and a surface of the base layer is dry-etched, and then a thin protective film made of a noble metal or alloy is formed by sputtering.

An eighth invention is a glass substrate for a magnetic disk or an optical glass element which is press-formed using the press-molding die according to the second, third, fourth, fifth or sixth invention.

A ninth aspect of the present invention is a glass substrate for a magnetic disk or an optical glass element which is press-formed by the press-forming die of the seventh aspect.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below.
This will be described with reference to the drawings.

(Embodiment 1) FIG. 1 is an enlarged sectional view showing the structure of a press-molding die for a magnetic disk substrate used in the present invention.

Reference numeral 1 denotes a base material of a press forming die made of glass having a glass transition temperature higher than the glass forming temperature. The kind of glass used for the base material 1 is not particularly limited. To prevent deformation due to repeated use,
It is preferable that the material has excellent mechanical strength at the highest possible temperature and that the coefficient of thermal expansion is small.

For example, quartz glass has a high glass transition temperature and is suitable as a base material for press molding.

Also, a material containing silicon dioxide as a main component and containing components such as aluminum oxide, magnesium oxide, zinc oxide, alkali metal oxide, and alkaline earth metal oxide is used as the base material 1 if necessary. be able to. In this case, it is necessary to use a glass material having a higher transition temperature than the molding temperature of the glass material to be molded, and desirably use glass whose components are adjusted to be 50 ° C. or more higher than the molding temperature. .

Further, the smoothness of the press-formed surface of the base material 1 is as follows:
For a magnetic disk, the thickness is suitably 5 nm or less, preferably 2 nm or less, more preferably 1 nm or less. Such a smooth surface can be obtained by polishing using cerium oxide fine particles.

Further, single-crystal alumina can also be used as a base material of a press molding die. It has a heat resistance exceeding 2000 ° C., and after lapping using diamond abrasive grains, by precision polishing using spherical fine particles of SiO 2, as in the case of glass, 5 nm or less necessary for magnetic disks, preferably Can obtain a smooth surface of 2 nm or less, more preferably 1 nm or less.

2 is titanium (Ti), vanadium (V),
Chromium (Cr), zirconium (Zr), niobium (N
b), a target made of a material containing at least one component among heat-resistant metals such as molybdenum (Mo), hafnium (Hf), tantalum (Ta), and tungsten (W) is sputtered to form a base material 1 The underlayer 2 formed on the surface of the substrate 1 has an underlayer 2 which increases the adhesive strength between the base material 1 and a protective film 3 described later, and is used repeatedly by a press molding die under high temperature and high pressure. To prevent the protective film 3 from peeling off.

This underlayer 2 is formed by a DC sputtering method, a high frequency sputtering method, a magnetron sputtering method, or an ion beam method at a gas pressure of 1 × 10 ^{−2 to} 1 × 10 ⁻⁴ Torr and a power density of 1 to 10 W / cm ² . It is appropriate that the film thickness is set to 0.05 to 3 μm by sputtering under the conditions. If the film thickness is less than this, sufficient adhesion strength cannot be obtained as the underlayer 2. The surface of the underlayer 2 is roughened, and the surface smoothness of the base material 1 is impaired.

3 is platinum (Pt), palladium (P
d), rhodium (Rh), ruthenium (Ru), iridium (Ir), osmium (Os), rhenium (R
e), a thin film-like protective film formed on the surface of the underlayer 2 by sputtering a target made of a noble metal-based metal or alloy material containing at least one kind of tantalum (Ta) element. The glass is prevented from adhering to the press surface of the base material 1 due to repeated press forming of the glass under high temperature and high pressure, and the surface smoothness of the press formed surface of the base material 1 is prevented from lowering due to surface roughness.

The protective film 3 is formed by a DC sputtering method, a high frequency sputtering method, a magnetron sputtering method or an ion beam method, at a gas pressure of 1 × 10 ^{−2 to} 1 × 10 ⁻⁴ Torr and a power density of 1 to 10 W / cm ² . It is appropriate that the film thickness is set to 0.1 to 5 μm by sputtering under the conditions, and a target made of a corresponding material can be formed by sputtering. As the sputtering method, a DC sputtering method, a high-frequency sputtering method, a magnetron sputtering method, or an ion beam sputtering method can be applied. If the film thickness is less than this, a sufficient adhesion strength cannot be obtained as the protective film 3. As with the underlayer 2, the surface of the protective film 3 is roughened, and the surface smoothness of the base material 1 is impaired.

The underlayer 2 and the protective film 3 are formed on the surface of the base material 1.
Before forming the substrate, if the surface of the base material 1 is dry-etched by high-frequency plasma such as argon,
The adhesion strength between the base material 1, the base layer 2, and the protective film 3 can be increased, but in this case, it is necessary to optimize the conditions so that the surface of the base material 1 is not roughened by dry etching.

FIG. 2 is a basic configuration diagram of a press molding machine using the press molding die of the present invention.

Reference numeral 4 denotes a glass material serving as a glass substrate for a magnetic disk, 5 denotes a barrel die for regulating the outer diameter and thickness of the glass substrate for a magnetic disk, and 6 denotes a press molding disposed below the inner side of the drum die 5. The lower die of the die, 7 is an upper die inserted into the upper inside of the trunk die 5 so as to be movable in the vertical direction in the figure, 8 is a heater for the die for heating the trunk die 5, and 11 is an upper die 7 , A piston cylinder for pressing the glass material 4 placed on the lower mold 6, a chamber 12 for covering a main body of the press molding machine,
Reference numeral 13 denotes a nitrogen inlet for introducing nitrogen gas into the chamber 12.

In the press molding machine having the above-described structure, the body mold 5, the lower mold 6, and the upper mold 7 are heated by the body heater 8, the lower mold heater 9, and the upper mold heater 10, respectively. In addition, nitrogen gas is introduced into the chamber 12 from the nitrogen gas inlet 13, and the glass material 4 placed on the lower mold 6 is pressurized by the upper mold 7 pushed down by the piston cylinder 11, and the magnetic disk is For manufacturing glass substrates.

Since the press forming of the glass substrate for a magnetic disk is performed in a low oxygen concentration atmosphere, oxidation of the die due to the high temperature of the press forming is prevented, and the durability of the die is improved.

Example 1 Next, a method for manufacturing a magnetic disk substrate having a smooth surface and a method for manufacturing a press mold for a glass substrate for a magnetic disk according to the present invention will be described in detail with reference to FIGS. explain.

First, the press-formed surfaces of the base material 1 of a pair of press-molding dies made of a cylindrical quartz glass having a diameter of 48 mm and a thickness of 15 mm were mirror-polished with fine diamond abrasive grains having a particle diameter of 0.1 μm. Then, polishing is performed using cerium oxide until the surface roughness becomes 0.5 nm. Then, the polished press-formed surface of the base material 1 is etched by high frequency plasma of argon gas under the conditions of argon gas pressure of 8 × 10 ⁻³ Torr and power density of 2 W / cm ² .

Next, polishing, magnetron high frequency sputtering
Method, argon gas pressure 5 × 10 ^-3Torr, power
Density 5W / cm^TwoTarget various materials under the conditions
To form an underlayer 2 having a thickness of 0.2 μm,
The surface of the layer 2 is coated with high-frequency plasma of argon gas.
Argon gas pressure 8x10^-3Torr, power density 2W /
cm^TwoEtching is performed under the following conditions.

Finally, a thin protective film 3 made of a noble metal alloy is formed on the etched surface of the underlayer 2 by magnetron high-frequency sputtering using various noble metals as targets. The press-molding dies of Samples 1 to 8 shown are manufactured. In addition, samples 1 to
Underlayer 2 and protective film 3 formed in press molding die of No. 8
Is shown in "Table 1".

As a comparative example, a press-forming mold without the underlayer 2 (sample 9 in Table 1) was used.
A press molding die (Sample 10 in Table 1) in which a protective film 3 is formed on the surface of a cemented carbide that has been mirror-polished with fine diamond abrasive grains of m is manufactured.

Then, the press-forming molds of Samples 1, 2,..., 9 or 10 were attached to the press-forming machine of FIG. 2, and a cylindrical glass material 4 made of soda lime glass and having a diameter of 35 mm. At a temperature of 700 ° C. and a pressing pressure of 60 kg / cm ^{2 in} a nitrogen atmosphere having an oxygen concentration of 0.1% or less.
Press molding for 2 minutes under the condition of
Continue to press-mold until cooled down, take out from the press-forming machine, a disk-shaped glass substrate is manufactured,
By subjecting this disc-shaped glass substrate to inner diameter processing, a glass substrate for a magnetic disk can be obtained.

Therefore, such press molding is performed for 3000 times.
After performing the rounding, the surfaces of the molding die and the glass substrate for the press-formed magnetic disk were measured at five points within a range of 34 μm square by AFM (atomic force microscope), and the average of the surface roughness (SRa) was measured. Calculated and evaluated, and when the surface of the glass substrate for a press-formed magnetic disk was measured with a three-dimensional surface roughness meter of an optical interference method and the number of coarse protrusions having a height of 50 nm or more was measured, Table 1 was obtained. The result is as follows.

[0047]

[Table 1]

As is clear from Table 1, the glass substrate for a magnetic disk manufactured by the press-molding die of the present invention (samples 1 to 8) is the same as the initial molded product even in the 3000th press-molded product. In comparison, there was almost no change in the surface roughness, and no formation of coarse projections was observed.

On the other hand, in the press-molding mold without the base layer 2 (sample 9), the surface
The occurrence of coarse protrusions of 0 nm or more is observed.

In the press-molding die (sample 10) in which the protective film 3 was formed on the surface of the cemented carbide base material, the surface roughness was rough from the initial molded product, and coarse projections were formed. The surface of this press molding die was magnified by an optical microscope at a magnification of 4.
When the mold surface was observed at a magnification of × 00, it was found that microscopic film peeling had partially occurred.

In this embodiment, a method of manufacturing a glass substrate for a magnetic disk by press molding using glass as a mold base material and a method of manufacturing a die for press-molding a glass substrate for a magnetic disk have been described. Similar results are obtained for glass elements.

Further, the same result can be obtained in the production of a glass substrate for a magnetic disk and an optical glass element also in a press molding die using single crystal alumina as a die base material.

(Embodiment 2) Next, a method of manufacturing a glass substrate for a magnetic disk having a fine pattern according to the present invention and a method of manufacturing a mold for press-molding the glass substrate for a magnetic disk will be described with reference to FIGS. This will be specifically described.

As a method for forming a fine pattern on the surface of the base material 1 of the press molding die, a resist is spin-coated, prebaked, and then subjected to conventional ultraviolet exposure or laser beam drawing with a laser beam. A resist pattern is formed by exposure and electron beam exposure for drawing with an electron beam. When dry etching is performed using the patterned resist as a mask, a pattern is formed on the surface of the base material 1.

For dry etching, argon gas, C
An etching method with good directivity, such as ion beam etching or electron cyclotron (ECR) resonance ion etching, in which a fluorine-based gas such as F ₄ or a mixed gas of a fluorine-based gas and oxygen can be used, is suitable.

Embodiment 2 Hereinafter, a method for manufacturing a glass substrate for a magnetic disk having a fine pattern and a method for manufacturing a die for press-molding the glass substrate for a magnetic disk will be specifically described.

As in Example 1, the diameter was 48 mm and the thickness was 15
The base material of a pair of press-molding molds made of quartz glass having a columnar shape of 1 mm and the press-formed surface of 1 are mirror-polished using fine diamond abrasive grains, and the surface roughness is adjusted to 0.5 nm with cerium oxide. Polish until it is. Then, a positive-type electron beam resist PMM is formed on the press-formed surface of the polished base material 1.
A was applied by a spin coating method, and prebaked at 70 ° C.
A resist pattern is formed by drawing and developing a fine pattern having concentric circles alternately with the above groove shape by an electron beam exposure method.

Next, the polished press-formed surface of the base material 1 is connected to an electron cyclotron (EC) using argon gas.
R) Degree of vacuum 6 × 10 ^-4 by resonance ion etching
Dry etching is performed under the conditions of Torr and power of 1000 W to form a fine pattern having a depth of 200 nm on the press-formed surface of the base material 1. As in the case of the first embodiment, the press-formed surface of the polished base material 1 on which a fine pattern is formed is etched with high-frequency plasma of argon gas, and then the base layer 2 is formed by magnetron high-frequency sputtering using various materials as targets. After the formation, the surface of the underlayer 2 is etched by high frequency plasma of argon gas.

Finally, a thin protective film 3 made of a noble metal alloy is formed on the etched surface of the underlayer 2 by magnetron high-frequency sputtering using various noble metals as targets. The press-molding dies of Samples 11 to 19 shown are manufactured. The specific compositions of the underlayer 2 and the protective film 3 formed on the press-molding dies of Samples 11 to 19 are shown in Table 2.

[0060] As the comparative example, the press molding surface of a cylindrical quartz glass is mirror-polished, to form a sputtered film of silicon oxide, on which is patterned by electron beam lithography, dry with CF ₄ gas Etching is performed to form a fine pattern. Then, a sputtered film of silicon carbide is formed on the press-formed surface of the base material 1 on which the polished and fine pattern is formed, and a protective film 3 made of carbon is formed by a plasma CVD method using a mixed gas of methane and hydrogen. The press mold (sample 20 in “Table 2”) is manufactured.

Then, samples 11, 12,..., 1
Attach the 9 or 20 press mold to the press machine of FIG. 2 and make a soda lime glass 35 mm in diameter.
In a nitrogen atmosphere having an oxygen concentration of 0.1% or less, a columnar glass material 4 of a
/ Cm 2 minutes after having pressed at ² conditions, the temperature is 4
Further press molding is continued until the temperature is cooled to 50 ° C., and if the glass substrate is taken out of the press molding machine, a disk-shaped glass substrate is manufactured. it can.

The surface and cross section of the glass substrate for a magnetic disk were evaluated using a scanning electron microscope. As a result, the accuracy of the land shape and groove shape of the press-formed surface of the press-molding die was determined. Has a clear transfer within a dimensional error range of 10%, and the surface roughness (SRa) of the land-shaped portion is 0.8 nm, which is the same level as the surface roughness of the press-formed surface of the press-molding die. Was.

Therefore, such press molding is performed for 3000 times.
After that, the surface of the groove-shaped portion of the fine pattern of the molding die and the press-molded surface and the surface of the land portion of the glass substrate for the press-formed magnetic disk were subjected to AFM (atomic force microscopy) in a range of 34 μm square. After measuring 5 places,
The average of the surface roughness (SRa) is calculated and evaluated, and the surface of the glass substrate for a press-formed magnetic disk is measured with a three-dimensional surface roughness meter of an optical interference method. Is measured, the result is as shown in Table 2.

[0064]

[Table 2]

As is clear from Table 2, the glass substrate for a magnetic disk manufactured by the press-molding die of the present invention (samples 11 to 19) is the same as that of the 3000th press-molded product. In comparison with the surface roughness, there was no change in the surface roughness, and no formation of coarse projections was observed.

On the other hand, in the comparative example (sample 20) in which the protective film 3 made of a carbon film was formed on the press-formed surface of the base material 1, the surface of this press-molding die was magnified by an optical microscope at a magnification of 8.
When observed at a magnification of × 00, a defect was thought to occur at the edge portion of the fine pattern, which was considered to be peeling of the protective film 3, and deformation of the fine pattern was also observed.

In this embodiment, a method for producing a glass substrate for a magnetic disk by press molding using glass as a mold base material and a method for press-molding a glass substrate for a magnetic disk having a land-shaped and groove-shaped fine pattern are described. Although the method for manufacturing the mold has been described, similar results can be obtained for an optical glass element having a fine pattern.

Further, the same results can be obtained in the production of a glass substrate for a magnetic disk and an optical glass element in a press molding die using single crystal alumina as a base material.

(Embodiment 3) Further, a method of manufacturing a convex optical glass element having a diameter of 2 mm or less and a method of manufacturing a press mold for the optical glass element, which could not be manufactured by the press molding method. This will be described more specifically with reference to FIG.

FIG. 3 shows the concept of the manufacturing process of the press molding die for the optical glass element of the present invention.

Reference numeral 14 denotes a lens sample to be manufactured (hereinafter, referred to as “lens sample”). Reference numeral 15 denotes an upper or lower surface of the lens sample 14 shown in FIG. The base material of the molding die 16 having the same shape as the curved surface or the flat surface, and the curved surface or the flat surface having the same smoothness. The base material 16 is formed by sequentially forming the base layer 17 and the protective film 18 on the surface of the base material 15. It is a mold for molding.

Reference numeral 19 denotes a press-formed surface of the molding mother die 16 pressed against one plane of the heated cylindrical glass so as to have the same shape as the curved surface or the flat surface of the upper or lower surface of the lens sample 14, and an equivalent smoothness. The base material 19 is a base material of a molding die having a surface having properties. The base material 19 is made of glass having a transition temperature of 50 ° C. or lower than the molding temperature of the glass used for the base material 15 of the molding base. Become. Reference numeral 20 denotes an underlayer 21 on the surface of the base material 19.
And a protective film 22 are sequentially formed.

In order to manufacture the molding die 20, first, a cylindrical glass press-molded surface is formed so as to have the same shape as the curved surface or the flat surface of one surface of the lens sample 14 and the same smoothness. After processing by a grinding method and polishing to form a base material 15 of a molding die, a base layer 1 is formed on the surface of the base material 15.
7 and the protective film 18 are sequentially formed to manufacture the molding master 16.

Next, the press-formed surface of the heated cylindrical glass is pressed by the press-formed surface of the molding die 16 to have the same shape as the curved surface or the flat surface of one surface of the lens sample 14, or an equivalent shape. By forming a concave or flat surface having smoothness to form a base material 19 of a molding die, and forming a base layer 21 and a protective film 22 on the surface of the base material 19 sequentially, the molding die is formed. 20 is manufactured.

The molding die 20 having the same shape as the other surface of the lens sample 14 or a flat surface or a concave surface having the same smoothness as the curved surface is also manufactured by the manufacturing method as described above. A pair of molding dies 20 is completed.

As a result, it is possible to produce a small-diameter convex or concave lens having a smooth surface property equivalent to that of a polished surface of glass that could not be produced conventionally.

Embodiment 3 Hereinafter, a method for manufacturing a convex optical glass element having a diameter of 2 mm or less and a method for manufacturing a press mold for the optical glass element will be described more specifically with reference to FIG.

First, two columnar quartz glasses each having a diameter of 1.8 mm and a length of 5 mm are ground, respectively, to have a radius of curvature of 0.4 mm.
After forming a preform 15 of a microlens forming base having a 9 mm convex press forming surface and a preforming base 15 of a microlens press forming base having a planar press forming surface, The press-formed surfaces of these base materials 15 are polished with cerium oxide abrasive grains until the surface roughness becomes 1 nm.

Then, the polished press surfaces of these base materials 15 are etched with high-frequency plasma of argon gas in the same manner as in Example 1, and then silicon carbide-platinum (SiC-Pt, An underlayer 17 made of Pt (50 wt%), and
The surface of the underlayer 17 is etched by high frequency plasma of argon gas. Further, a protective matrix 18 made of a platinum-rhodium (Pt-Rh, Rh content 20 wt%) alloy thin film is formed on the surface of the underlayer 17 by a magnetron high-frequency sputtering method, thereby manufacturing the molding master 16.

Next, the molding master 16 is attached to the press molding machine shown in FIG. 2 to produce a microlens molding die 20. That is, a cylindrical Pyrex glass material having a diameter of 6 mm and a thickness of 6 mm is placed between the molding die 16 and a die having a flat press-formed surface, and the temperature is 750 ° C. and the pressing pressure is 50 kg / cm ^2. After press-molding for 5 minutes under the conditions described above, after further pressing until the temperature is cooled to 500 ° C., when the glass material is taken out from the press-forming machine, the concave-shaped press-formed surface having a radius of curvature of 0.9 mm is formed. A base material 19 of a molding die having the same is formed.

Further, one surface of a cylindrical Pyrex glass material having a diameter of 6 mm and a thickness of 6 mm is polished to form a base material 19 of a molding die having a planar shape on a press molding surface.

Thus, the press-formed surfaces of the base materials 19 of the two molding dies are each etched with high-frequency plasma of argon gas in the same manner as in Example 1, and then subjected to magnetron high-frequency sputtering using various materials as targets. An underlayer 21 is formed. Then, the surface of the base layer 21 is etched with high-frequency plasma of argon gas, and the protective film 22 is formed by a magnetron high-frequency sputtering method using various noble metals as targets, thereby obtaining samples 21 to 29 shown in Table 3 below. A pair of molding dies 20 serving as an upper mold or a lower mold is manufactured. The specific compositions of the underlayer 21 and the protective film 22 formed on the molding dies 20 of the samples 21 to 29 are shown in Table 3.

As a comparative example, a molding die in which magnesium fluoride was vapor-deposited on the press molding surface (Sample 3 in Table 3)
0) is manufactured.

Then, samples 21, 22,..., 2
A press molding die of 9 or 30 was attached to the press molding machine of FIG. 2, and a lead oxide optical glass having a PbO content of 70 wt%, a SiO ₂ content of 27 wt%, and a balance of trace components was prepared. Glass material processed into a spherical shape of 0.7 mm,
In a nitrogen atmosphere with an oxygen concentration of 0.1% or less, press molding is performed for 2 minutes at a temperature of 520 ° C. and a pressing pressure of 40 kg / cm ² , and further press molding is continued until the temperature is cooled to 300 ° C. Then, by taking it out of the press molding machine, a microlens is manufactured.

Therefore, such press molding is performed for 3000 times.
After performing the rounding, the surface of the molding die 20 and the surface of the microlens molded by the molding die 20 were measured at five places by a three-dimensional surface roughness meter of an optical interference method, and the surface roughness (RMS Value) is calculated and evaluated. The results and the observation of the surface condition of the molding die 20 are shown in "Table 3".

[0086]

[Table 3]

As is apparent from Table 3, the microlenses manufactured by the press molds (samples 21 to 29) of the present invention were compared with the initial molded products even in the 3000th press molded product. While the surface roughness (RSM value) did not change, in the comparative example (sample 30) in which the protective film made of magnesium fluoride was formed, the film was peeled off and the glass material was removed until the press molding reached 3000 times. Welding occurred.

[0088]

As described above, according to the present invention,
There is an effect that a press mold having an ultra-smooth surface property and a high-precision fine pattern or a precise shape corresponding to a glass substrate for a magnetic disk or an optical glass element to be manufactured can be easily manufactured.

According to the present invention, when press molding is performed using the press molding die of the present invention, a glass substrate for a magnetic disk or an optical glass element on which the shape of the die is transferred with high precision and high precision. Can be easily manufactured. Further, according to the present invention, there is an effect that a metal mold for press molding of a microlens, which cannot be produced by the conventional press molding method, can be produced inexpensively and in large quantities by the press molding method.

Further, according to the present invention, even if the press molding die is used repeatedly over a long period of time, there is an effect that the deterioration of the die is prevented and the life of the die is extended.

Further, according to the present invention, from the aforementioned effects,
There is an effect that high-quality glass substrates for magnetic disks or optical glass elements can be manufactured inexpensively and in large quantities.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a mold for press-molding a glass substrate for a magnetic disk of the present invention.

FIG. 2 is a basic configuration diagram of a press forming machine using the press forming die of the present invention.

FIG. 3 is a conceptual diagram of a manufacturing process of a mold for press-molding an optical glass element of the present invention.

[Explanation of symbols]

 Reference Signs List 1,19 Base material of molding die 2,17,21 Base layer 3,18,22 Protective film 4 Glass material 5 Body mold 6 Lower mold 7 Upper mold 8 Body heater section 9 Lower mold heater section 10 Upper Mold heater section 11 Piston cylinder 12 Chamber 13 Nitrogen gas inlet 14 Lens sample 15 Mold base material 16 Mold matrix 20 Mold mold

Claims (9)

[Claims] 1. A press-formed surface of a mold base material made of an oxide, which is provided with a tungsten (W), a platinum (Pt), a palladium (Pd), a rhodium (Rh), a ruthenium (Ru), an iridium (A) through an underlayer. Ir), osmium (Os),
In a press-molding mold in which a thin protective film made of at least one kind of metal or alloy of rhenium (Re) and tantalum (Ta) is formed, the underlayer is made of titanium (Ti), vanadium (V ), Chromium (Cr), zirconium (Zr), niobium (N
b) a press-molding die comprising at least one metal or alloy of molybdenum (Mo), hafnium (Hf), tantalum (Ta), and tungsten (W). 2. A press forming surface of a base material of a forming die made of glass or single crystal alumina having a smooth surface has tungsten (W), platinum (Pt), palladium (Pd), rhodium (Rh), A thin protective film made of at least one metal or alloy of ruthenium (Ru), iridium (Ir), osmium (Os), rhenium (Re), and thallium (Ta) is made of titanium (Ti), vanadium ( V), chromium (Cr), zirconium (Z
r), niobium (Nb), molybdenum (Mo), hafnium (Hf), tantalum (Ta), and tungsten (W) via an underlayer made of at least one metal or alloy. A mold for press molding characterized by the following. 3. A press-formed surface of a base material of a molding die made of glass or single-crystal alumina formed with a fine pattern corresponding to a glass product includes tungsten (W), platinum (Pt), and palladium (Pd). , Rhodium (Rh), ruthenium (Ru), iridium (Ir), osmium (Os), rhenium (Re), and thallium (Ta). ), Vanadium (V), chromium (C
r), zirconium (Zr), niobium (Nb), molybdenum (Mo), hafnium (Hf), tantalum (T
a) A press-molding die formed through an underlayer made of at least one kind of metal or alloy of tungsten (W). 4. A press-formed surface of a base material of a molding die made of glass or single-crystal alumina having a shape corresponding to an optical glass element is provided with tungsten (W) and platinum (P).
t), palladium (Pd), rhodium (Rh), ruthenium (Ru), iridium (Ir), osmium (O
s), rhenium (Re), tantalum (Ta), and at least one kind of metal or alloy is formed of a thin protective film made of titanium (Ti), vanadium (V), chromium (Cr), zirconium (Zr). , Niobium (Nb), molybdenum (Mo), hafnium (Hf), tantalum (T
a) A press-molding die formed through an underlayer made of at least one kind of metal or alloy of tungsten (W). 5. At least a press-formed surface of a base material of a molding die obtained by dry-etching glass or single-crystal alumina having a smooth surface has tungsten (W), platinum (P)
t), palladium (Pd), rhodium (Rh), ruthenium (Ru), iridium (Ir), osmium (O
s), rhenium (Re), tantalum (Ta), and at least one kind of metal or alloy is formed of a thin protective film made of titanium (Ti), vanadium (V), chromium (Cr), zirconium (Zr). , Niobium (Nb), molybdenum (Mo), hafnium (Hf), tantalum (T
a) a press formed by forming a base layer made of at least one kind of metal or alloy of tungsten (W) by a sputtering method, dry-etching the base layer, and then forming the base layer by a sputtering method; Mold for molding. 6. A press-formed surface of a base material of a molding die obtained by forming a fine pattern corresponding to a glass product on glass or single-crystal alumina having a smooth surface by dry etching. , Platinum (Pt), palladium (Pd), rhodium (Rh), ruthenium (Ru),
A thin protective film made of at least one metal or alloy of at least one of iridium (Ir), osmium (Os), rhenium (Re), and tantalum (Ta) is made of titanium (Ti), vanadium (V), chromium ( Cr), zirconium (Zr), niobium (Nb), molybdenum (M
o), an underlayer made of at least one metal or alloy of hafnium (Hf), tantalum (Ta), and tungsten (W) is formed by sputtering, and the underlayer is dry-etched, and then sputtered. A mold for press molding characterized by being formed by: 7. A press-formed surface of a base metal of a molding die obtained by dry-etching a surface of glass press-formed by a molding die having a glass product shape has tungsten (W), platinum (Pt). ), Palladium (Pd), rhodium (Rh), ruthenium (Ru), iridium (I
r), osmium (Os), rhenium (Re), tantalum (Ta), and a thin protective film made of at least one metal or alloy made of titanium (Ti), vanadium (V), chromium (Cr) , Zirconium (Zr),
Niobium (Nb), molybdenum (Mo), hafnium (H
f), tantalum (Ta) and tungsten (W)
A press molding die, wherein a base layer made of at least one kind of metal or alloy is formed by a sputtering method, and the base layer is dry-etched and then formed by a sputtering method. 8. A glass substrate for a magnetic disk or an optical glass element which is press-formed using the press-molding die according to claim 2, 3, 4, 5 or 6. 9. A glass substrate for a magnetic disk or an optical glass element, which is press-formed by the press-molding die according to claim 7.