JP2002201033A - Mold for forming optical element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mold for press forming capable of repeatedly press forming an optical glass element having various kinds of shape which could not be attained by conventional grinding/polishing process, and to provide a glass element obtained by press forming using the mold for press forming. SOLUTION: This mold for press forming an optical glass element is characterized in that the forming surface comprises a ground processed layer 2 comprising an electroless nickel-phosphorus alloy (Ni-P) plated film which is obtained by dispersed co-deposition of fine particles of at least a kind selected from nitrides, carbides, borides and oxides on the base material of the mold 1. This glass element is obtained by press forming using the mold.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a press mold for an optical glass element, and more particularly to a press mold for an optical glass element used for press molding a high precision optical glass element. The present invention relates to a glass element press-formed using the press-forming mold.

[0002]

2. Description of the Related Art In order to repeatedly mold a high-precision optical glass element by press molding, the mold material is stable at the molding temperature of the glass, has excellent oxidation resistance, is inert to the glass, It is necessary to have something with excellent mechanical strength so that the shape accuracy does not collapse when it is done, but on the other hand,
It must be easy to process and easy to machine.

As a mold material which satisfies the above-mentioned conditions necessary for the press molding mold of an optical glass element to some extent, a mixed material of titanium carbide (TiC) and a metal (for example, JP-A-59-121126) or a super hard Noble metal thin film formed on an alloy base material (for example, Japanese Patent Application Laid-Open No. 62-9633)
No. 1) has been studied.

[0004]

However, conventional mold materials cannot satisfy all of the above conditions. For example,
When a mixed material of titanium carbide (TiC) and a metal is used as a mold material, although it is very hard and has excellent mechanical strength, it is inferior in workability and difficult to perform high-precision work. Further, lead (P) which is a constituent component of the optical glass element
It has the disadvantage that it easily reacts with b) and alkali elements.

[0005] In a mold in which a noble metal thin film is formed on a cemented carbide base material, if the cemented carbide is machined using a diamond grindstone, the diamond grindstone is severely worn, and precise shape machining is difficult. Special processing equipment is required. Further, there is a problem that the processing time is long and the die cost is very high.

As a remedy, a thin film having good adhesion to the base material is formed on a cemented carbide base material, and an electroless Ni-P plating film, for example, is formed on the thin film as a film which can be easily processed precisely. A method of forming an alloy thin film as a protective film (for example, Japanese Patent Application Laid-Open No. 3-23230) has been studied.

However, in this method, electroless Ni-P
There was a problem that the heat resistance and strength of the plating film were low and the film was peeled off during molding. Therefore, there is a problem that the glass that can be formed by this mold is limited to a part of glass having a special composition having a very low melting point.

[0008] As described above, the conventional mold material has not yet satisfied all of the requirements for the mold material described above.

The present invention solves such a conventional problem,
Provide a press-molding die that can repeatedly press-mold optical glass elements having various shapes that could not be realized by conventional grinding and polishing, and a glass element that is press-formed using the press-forming die. The purpose is to do.

[0010]

In order to achieve the above object, a first invention according to the present invention is directed to an optical element molding die used for press molding of an optical element made of glass. A formed layer made of an electroless nickel-phosphorus alloy plating (Ni-P) film in which at least one kind of fine particles selected from nitrides, carbides, borides and oxides are dispersed and codeposited; It is characterized by the following.

It has been found that when a substance having a higher hardness and strength than nickel and phosphorus (P) is dispersed and co-deposited in electroless nickel-phosphorus alloy plating, the hardness and strength of the plating film are remarkably improved.

Therefore, in the above configuration, electroless nickel-phosphorus alloy plating (Ni-
P) The coating has sufficient strength, hardness and heat resistance as a glass element molding die, and is excellent in workability (cutting is possible). The mechanical strength required for the mold is mainly attributable to the mold base material. Therefore, necessary for the high melting point optical glass element molding die, excellent in oxidation resistance, inert to glass, excellent in mechanical strength that does not lose shape accuracy when pressed, and excellent in workability, Completely satisfies the condition that precision machining must be easy. In the present invention, the term “fine particles” refers to particles having a diameter of 1 μm.
The following particles are shown.

The substance to be dispersed and eutectoid may not necessarily be a nitride, carbide, boride or oxide as long as it is higher in hardness and strength than nickel and phosphorus (P). If a material that meets hardness and strength standards and is thermally stable is selected, nitrides, carbides,
Either boride or oxide.

According to a second aspect of the present invention, the molding surface is processed into a desired shape by cutting, and a diamond film, a diamond-like carbon film, a hydrogenated amorphous carbon film (iC film) is formed on the molding surface. ) And hard carbon films
It is characterized in that the seed film is coated.

In the above configuration, the electroless nickel-phosphorus alloy plating (Ni-P) film in which fine particles are dispersed and eutectoid has sufficient strength and hardness and can be cut, so that precision processing is easy. Can be. Furthermore, no special equipment is required for processing. Processing time is also short. Therefore, the mold cost can be extremely reduced. Furthermore, it has become possible to produce a surface that can only be made by cutting. In addition, since this coating has excellent heat resistance, it can be used for molding high melting point glass. Further, in the above configuration, by using a coating of one kind of film selected from a diamond film, a diamond-like carbon film, a hydrogenated amorphous carbon film (iC film) and a hard carbon film on the molding surface, In addition to preventing fusion of the glass with the mold and obtaining good mold releasability between the mold and the glass. Therefore, the mold of the present invention satisfies all the necessary conditions required as the mold material described above.
This makes it possible to repeatedly press-mold optical glass having various shapes, which could not be realized by conventional grinding and polishing.

According to a third aspect of the present invention, the nitride contained in the electroless nickel-phosphorus alloy plating (Ni-P) coating on the mold base material is titanium nitride (TiN), tantalum nitride (TaN), Zirconium nitride (ZrN), vanadium nitride (VN), silicon nitride (Si ₃ N ₄ ), chromium nitride (C
r ₂ N, CrN), aluminum nitride (AlN), boron nitride (BN), hafnium nitride (HfN), nickel nitride (NiN), iron nitride (FeN), and cobalt nitride (CoN). It is characterized by the following.

The nitride has higher hardness and strength than nickel and phosphorus (P), and is thermally stable. Therefore, the hardness, strength, and heat resistance of the electroless nickel-phosphorus alloy plating (Ni-P) film are remarkably improved by dispersing and eutecting these fine particles, and the film can be favorably used.

According to a fourth aspect of the present invention, the carbide contained in the electroless nickel-phosphorus alloy plating (Ni-P) coating on the mold base material is titanium carbide (TiC), tantalum carbide (TaC), Zirconium (ZrC), vanadium carbide (VC), silicon carbide (SiC), chromium carbide (Cr
₂ C ₃ ), boron carbide (B ₄ C), hafnium carbide (Hf
C), niobium carbide (NbC), tungsten carbide (W
C), nickel carbide (NiC), iron carbide (Fe ₃ C), and cobalt carbide (CoC).

The above carbides have higher hardness and strength than nickel and phosphorus (P), and are thermally stable. Therefore, the hardness, strength, and heat resistance of the electroless nickel-phosphorus alloy plating (Ni-P) film are remarkably improved by dispersing and eutecting these fine particles, and the film can be favorably used.

According to a fifth aspect of the present invention, the boride contained in the electroless nickel-phosphorus alloy plating (Ni-P) coating on the mold base is titanium boride (TiB ₂ ), tantalum boride ( TaB ₂ ), zirconium boride (Zr
B ₂ ), vanadium boride (VB ₂ ), chromium boride (C
rB ₂ ), hafnium boride (HfB ₂ ), niobium boride (NbB ₂ ), manganese boride (MnB ₂ ), nickel boride (NiB), iron boride (FeB) and cobalt boride (CoB). Characterized in that it is at least one kind.

The above boride has higher hardness and strength than nickel and phosphorus (P), and is thermally stable. Therefore,
By dispersing and eutecting these fine particles, the hardness, strength, and heat resistance of the electroless nickel-phosphorus alloy plating (Ni-P) coating are dramatically increased, and it can be used favorably.

According to a sixth aspect of the present invention, the oxide contained in the electroless nickel-phosphorus alloy plating (Ni-P) coating on the mold base is titanium oxide (TiO ₂ ) or tantalum oxide (Ta ₂ ). O ₅ ), zirconium oxide (ZrO ₂ ), silicon oxide (SiO ₂ ), chromium oxide (Cr ₂ O ₃ ), alumina (Al ₂ O ₃ ), yttrium oxide (Y ₂ O ₃ ), and tungsten oxide (WO ₃ ) At least one selected from the group consisting of:

The above oxide has higher hardness and strength than nickel and phosphorus (P), and is thermally stable. Therefore, the hardness, strength, and heat resistance of the electroless nickel-phosphorus alloy plating (Ni-P) film are remarkably improved by dispersing and eutecting these fine particles, and the film can be favorably used.

A seventh invention according to the present application is characterized in that the desired shape is a shape that cannot be processed by grinding and polishing.

An eighth invention according to the present application is a glass element press-formed using a mold that cannot be manufactured by grinding and polishing. Conventionally, such glass elements could not be produced because mold processing was not possible.

With the above configuration, it is possible to mass-produce an optical element having a shape which has not been realized conventionally.

[0027]

Embodiments of the present invention will be described below with reference to the drawings.

Examples 1 to 15 An electroless nickel-phosphorus alloy plating (Ni-P) film in which fine particles were dispersed and codeposited to a thickness of 10 mm was coated on a hard metal having a diameter of 16 mm, and the radius of curvature was 10 mm. A pair of optical glass lenses having upper and lower molds having concave molding surfaces were formed into a press-molding mold shape by grinding using a cemented carbide tool.

Next, the molding surface was finished to a very high precision by cutting with a diamond cutting tool. As described above, by cutting the electroless nickel-phosphorus alloy plating (Ni-P) film in which fine particles are dispersed and eutectoid, a high-precision surface conventionally obtained only by polishing is obtained. . In addition, it has become possible to produce surfaces that can only be made by cutting. Table 1 shows the types of nitrides, carbides, borides, and oxides used for the dispersion-eutectoid. FIG.
In the figure, 1 is a mold base material (a cemented carbide), and 2 is an electroless nickel-phosphorus alloy plating (Ni-P) film in which fine particles processed by cutting are dispersed and eutectoid.

In this example, a cemented carbide was used as the base material. However, if the material had excellent strength and heat resistance, it was acceptable. Examples of the test include cermet, silicon nitride, and the like containing titanium carbide or titanium nitride as a main component.

In order to disperse and eutect fine particles, Ni is used.
The plating may be performed in a state where the added fine particles are uniformly distributed in the -P solution.

Next, a diamond film, a diamond-like carbon film, a hydrogenated amorphous carbon film (i-C
Film) and a hard carbon film.

The diamond thin film is formed by a microwave plasma CVD method, a hot filament CVD method, a plasma jet method, an electron cyclotron resonance plasma CVD method, or the like, and a diamond-like carbon film, a hydrogenated amorphous carbon film (iC film), Hard carbon film is plasma CVD
Method, ion beam sputtering method, ion beam evaporation method,
It is formed by a plasma sputtering method or the like. The gases used for forming the film include methane, ethane, and carbon-containing gases.
Hydrocarbons such as propane, ethylene, benzene, and acetylene; halogenated hydrocarbons such as methylene chloride, carbon tetrachloride, chloroform, and trichloroethane; alcohols such as methyl alcohol and ethyl alcohol; (CH ₃ ) ₂ C
Ketones such as O and (C ₆ H ₅ ) ₂ CO; gases such as CO and CO ₂ and mixtures of these gases with gases such as N ₂ , H ₂ , O ₂ , H ₂ O and Ar Is mentioned.

Next, an optical element was formed by an electroless nickel-phosphorus alloy plating (Ni-P) coating type in which the fine particles shown in Table 1 obtained as described above were dispersed and codeposited.

The glass is SK12 (produced by OHARA CORPORATION, n
d1.58313, vd59.4, Tg550 ° C, At
588 ° C., see Table 2 for composition) and S-TIH6 (Ohara Co., Ltd., lead-free SF6 equivalent glass, nd 1.
80518, vd 25.4, Tg 604 ° C, At63
It was processed into a ball lens using 0 ° C. and the composition shown in Table 3).

FIG. 2 schematically shows the apparatus used for the molding test. In FIG. 2, 24 is a chamber, 25 is an upper shaft, 26
Is a lower shaft, 27 is a block with a built-in heater (heater block), 28 is a heater block, 29 is an upper mold,
0 is a lower mold, 31 is glass, and 32 is a hydraulic cylinder.

After the chamber 24 was evacuated by a vacuum pump (not shown), N ₂ gas was introduced,
After the inside of the heater 4 is set to the N ₂ atmosphere, the heater blocks 27, 2
8, the upper mold 29 and the lower mold 30 are heated to a temperature (SK1) corresponding to 10 ⁹ d · Pa · s in the viscosity of the glass to be formed.
2: 640 ° C, S-TIH6: 665 ° C)
The upper shaft 25 was pulled up by the hydraulic cylinder 32, and a molding material (ball lens) was placed on the lower die 30 by an auto hand (not shown). After holding at the mold temperature as it is for 1 minute, the upper shaft 25 is lowered by the hydraulic cylinder 32, and the ball lens is moved to the upper mold 29 and the lower mold 30 by 3,000.
Pressed with N force for 3 minutes. Thereafter, cooling is performed at 70 ° C./min.
Was raised, and the molded product 31 on the lower die 30 was taken out by an automatic hand (not shown). Subsequently, the molded product 31 was taken out of the chamber 24 through a replacement device (not shown). The upper and lower molds were heated again, and the above operation was repeated to form 5,000 shots.

As a result of molding at 5,000 shots, good moldability was obtained in all the molds of the examples shown in Table 1. On the other hand, in Comparative Example 1 in which no dispersion eutectoid was used, several sh
The plating layer was peeled off by the molding of ot.

Example 16 After the step-like mold shown in FIG. 3 was machined by cutting with a carbide tool, the molding surface was finished with very high precision by cutting with a diamond tool. As described above, electroless nickel-phosphorus alloy plating (Ni-P) in which fine particles provided on a base material (hard metal) are dispersed and eutectoid.
By cutting the coating film, it is possible to process a surface that cannot be obtained by conventional grinding and polishing.

The same test as described above was conducted for this mold, but exactly the same results were obtained. This molded product is a kind of diffraction grating, and is an example of a so-called fine optical element.

The shapes that cannot be processed by grinding and polishing here include elements having a free-form surface (so-called free-form surface elements), elements having a fine pattern (so-called fine optical elements), various shapes (spherical, aspherical, flat, etc.). ) Are combined with each other to form a mold having a complicated shape that cannot be manufactured by polishing or are bonded together, and a combination of these shapes.

[0042]

[Table 1]

[0043]

[Table 2]

[0044]

[Table 3]

[0045]

As described above, according to the first aspect of the present invention, in producing a press molding die for an optical glass element, electroless nickel-phosphorus alloy plating in which fine particles are dispersed and codeposited on a base material. By using the cutting layer composed of the (Ni-P) coating on the molding surface, all the conditions required for the glass molding die material are satisfied. According to the second aspect of the present invention, the molding surface is formed by cutting. And formed on the molding surface with a film selected from a diamond film, a diamond-like carbon film, a hydrogenated amorphous carbon film (i-C film), and a hard carbon film. This is to provide a press molding die capable of optical glass press molding of various shapes.By repeatedly press molding optical glass using this mold, it is possible to obtain a shape that could not be obtained by conventional press molding. Low cost of Manabu glass element, and it has become possible to mass production.

According to the third aspect of the present invention, the nitride dispersed and eutectoidally deposited on the electroless nickel-phosphorus alloy plating (Ni-P) film is titanium nitride (TiN) or tantalum nitride (Ta).
N), zirconium nitride (ZrN), vanadium nitride (VN), silicon nitride (Si ₃ N ₄ ), chromium nitride (Cr ₂
N, CrN), aluminum nitride (AlN), boron nitride (BN), hafnium nitride (HfN), nickel nitride (NiN), iron nitride (FeN), and cobalt nitride (Co
By using at least one type selected from N), mirror-finish processing is possible while being able to withstand the temperature at which the high-melting glass is formed, and cutting can be performed. It is now possible to produce shapes that were difficult to process.

According to the fourth aspect of the present invention, the carbides dispersed and eutectoidally deposited in the electroless nickel-phosphorus alloy plating (Ni-P) film are titanium carbide (TiC) and tantalum carbide (Ta).
C), zirconium carbide (ZrC), vanadium carbide (VC), silicon carbide (SiC), chromium carbide (Cr
₂ C ₃ ), boron carbide (B ₄ C), hafnium carbide (Hf
C), niobium carbide (NbC), tungsten carbide (W
C), nickel carbide (NiC), iron carbide (Fe ₃ C), and cobalt carbide (CoC) make it at least one type, so that it can withstand the temperature at which high-melting glass is formed and can be cut. However, mirror processing is possible, and the time and cost for processing the mold are reduced, and a shape that has been difficult to process can be manufactured.

According to the fifth aspect of the present invention, there is provided an electroless
Kel-phosphorus alloy plating (Ni-P)
The boride is titanium boride (TiB_Two), Tantalum boride
(TaB_Two), Zirconium boride (ZrB_Two)
Vanadium (VB)_Two), Chromium boride (CrB_Two)
Hafnium borohydride (HfB_Two), Niobium boride (Nb
B _Two), Manganese boride (MnB)_Two), Nickel boride
(NiB), iron boride (FeB) and cobalt boride
(CoB) by at least one kind selected from
And withstands the temperature at which high-melting-point glass is formed.
Mirroring can be performed while machining is possible,
Less time and cost to process and difficult to process
Can be manufactured.

According to the sixth aspect of the present invention, there is provided an electroless
Kel-phosphorus alloy plating (Ni-P)
Oxide is titanium oxide (TiO 2)_Two), Tantalum oxide (T
a_TwoO _Five), Zirconium oxide (ZrO)_Two), Silicon oxide
(SiO_Two), Chromium oxide (Cr_TwoO_Three), Alumina (A
l_TwoO_Three), Yttrium oxide (Y_TwoO_Three) And oxidized tongue
Stainless (WO_ThreeAt least one selected from
Withstands the temperature at which high melting glass is formed, and
Mirror finishing is possible while cutting is possible,
The time and cost of processing the mold are reduced, and
It has become possible to produce shapes that were difficult to perform.

According to the seventh and eighth aspects of the present invention, it is possible to produce a mold having a shape which cannot be produced by the conventional grinding and polishing method, and thus to obtain a glass element having a shape which cannot be obtained by conventional press molding. Is now available.

Accordingly, it has become possible to produce optical glass elements having shapes which could not be obtained by conventional press molding at low cost and in large quantities.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a first embodiment of the present invention.

FIG. 2 is a schematic sectional view of a press forming apparatus for an optical element.

FIG. 3 is a schematic sectional view of a press mold for an optical element.

[Explanation of symbols]

Reference Signs List 1 mold base material 2 electroless nickel-phosphorus alloy plating (Ni-P) coating (fine formed surface processed by cutting) in which fine particles are dispersed and eutectoidally 24 chamber 25 upper shaft 26 lower shaft 27 heater block 28 heater block 29 Upper mold 30 Lower mold 31 Glass 32 Hydraulic cylinder

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Shigeru Hashimoto 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Keiji Hirabayashi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Co., Ltd. F-term (reference) 4G015 HA01

Claims (8)

[Claims] 1. An optical element molding die used for press molding of an optical element made of glass, wherein a nitride,
At least one selected from carbides, borides and oxides
A press-molding die for an optical glass element, characterized in that the molding surface has a cutting layer made of an electroless nickel-phosphorus alloy plating (Ni-P) film in which more than one kind of fine particles are dispersed and eutectoid. 2. The molding surface is processed into a desired shape by cutting, and a diamond film, a diamond-like carbon film, a hydrogenated amorphous carbon film (i-C
And a hard carbon film. 4. A mold for press-molding an optical glass element, comprising a film selected from the group consisting of a film and a hard carbon film. 3. The nitride contained in the electroless nickel-phosphorus alloy plating (Ni-P) coating on the mold base material is titanium nitride (TiN), tantalum nitride (TaN), zirconium nitride (ZrN), vanadium nitride. (VN), silicon nitride (Si ₃ N ₄ ), chromium nitride (Cr ₂ N, CrN), aluminum nitride (AlN), boron nitride (BN), hafnium nitride (HfN), nickel nitride (NiN), iron nitride ( A press mold for an optical glass element, wherein the mold is at least one selected from FeN) and cobalt nitride (CoN). 4. The carbide contained in the electroless nickel-phosphorus alloy plating (Ni-P) coating on the mold base material is titanium carbide (TiC), tantalum carbide (TaC), zirconium carbide (ZrC), vanadium carbide ( VC), silicon carbide (SiC), chromium carbide (Cr ₂ C ₃ ), boron carbide (B
₄ C), hafnium carbide (HfC), niobium carbide (Nb
C), tungsten carbide (WC), nickel carbide (Ni
C), iron carbide (Fe ₃ C) and cobalt carbide (CoC)
A mold for press-molding an optical glass element, wherein the mold is at least one member selected from the group consisting of: 5. The boride contained in the electroless nickel-phosphorus alloy plating (Ni-P) coating on the mold base material is titanium boride (TiB ₂ ), tantalum boride (TaB ₂ ), zirconium boride (TaB ₂ ). ZrB ₂ ), vanadium boride (V
B ₂ ), chromium boride (CrB ₂ ), hafnium boride (HfB ₂ ), niobium boride (NbB ₂ ), manganese boride (MnB ₂ ), nickel boride (NiB), iron boride (FeB) and A press-molding die for an optical glass element, which is at least one selected from cobalt boride (CoB). 6. The oxide contained in the electroless nickel-phosphorus alloy plating (Ni-P) coating on the mold base material is titanium oxide (TiO ₂ ), tantalum oxide (Ta ₂ O ₅ ), zirconium oxide (ZrO). ₂ ) at least one selected from silicon oxide (SiO ₂ ), chromium oxide (Cr ₂ O ₃ ), alumina (Al ₂ O ₃ ), yttrium oxide (Y ₂ O ₃ ) and tungsten oxide (WO ₃ ) A press molding die for an optical glass element, characterized in that: 7. A press-molding die for an optical glass element, wherein the desired shape is a shape that cannot be processed by grinding and polishing. 8. A glass element press-formed using the press-molding die according to claim 7.