JP2820728B2 - Composite mold for optical parts molding - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention relates to optical measuring instruments such as cameras, microscopes, and telescopes, video equipment such as video cameras, video movies, and video discs, audio equipment, facsimile machines, and laser beam printers. Used as parts of optical equipment such as office equipment such as copiers, mainly lenses, prisms,
The present invention relates to a composite mold for molding an optical component, which is suitable for molding a compact disk or a magneto-optical disk.

(Prior Art) Conventionally, materials such as die steel, stainless steel, and cemented carbide have been used as molds for forming optical parts having a desired shape by heating and softening glass or plastic and then applying pressure. I have. However, these molds have a problem in that they have a short life due to the mold releasability or the surface accuracy of the molded optical component in the case of a mold and a work material that has been softened by heating, particularly, a glass that softens at a high temperature. Many molds for molding optical parts for solving this problem have been proposed, representative of which are JP-A-60-118638, JP-A-63-123822 and JP-A-63-297223. There is an official gazette.

(Problems to be solved by the invention) JP-A-60-118638 discloses that the surface of a substrate is 0.5 to 10 μm.
A mold for forming glass formed with a coating layer made of TiC, TiN or Ti (C, N) having a thickness of m is disclosed. JP-A-63-123822 discloses a mold for molding an optical glass element having at least a molding surface formed by a coating layer containing chromium and carbon as main components. Further, JP-A-63-
Japanese Patent No. 297223 discloses a molten glass forming tool in which a boride, carbide, nitride, silicide, or oxide is coated on a surface of a base material in a thickness of 1 to 10 μm in a single layer or a plurality of layers. Discloses a molten glass forming tool including a coating layer of TiB ₂ , TiC, TaC, TiN, TaN, Al ₂ O ₃ , and ZrO ₂ .

Compared to conventional stainless steel and chromium steel, these glass forming tools or molds form various coating layers to prevent reaction with glass, control roughening of the surface of the mold, and separate glass. Although excellent in moldability, it is easy to color the molded glass when it is repeatedly molded, especially the surface accuracy of the mirror-polished molded surface is transferred to the molded glass surface And the glass surface is easily roughened, and the releasability of the glass after the molding process is reduced.

The present invention has solved the above-mentioned problems, and specifically includes ceramic sintered bodies, cermets, cemented carbides, alloys having a high melting point metal as a main component, heat-resistant steel, and super-heat-resistant alloys. It is an object of the present invention to provide a composite mold for molding optical components, in which a coating layer composed of a single layer or a plurality of layers containing chromium oxide as a main component is formed on the surface of a substrate.

(Means for Solving the Problems) One of the present inventors is concerned with glass used in various applications as an optical component, particularly from the viewpoints of wettability, foamability, corrosiveness, and colorability with respect to molten glass. After examining molding molds and obtaining the knowledge that sintered bodies containing a chromium compound containing chromium and oxygen as a main component are excellent as glass molding mold materials, Japanese Patent Application No. 63-176535 (Patent No. No. 1783120, Tokuhei 4-74292
No.). By further developing the viewpoint of Japanese Patent Application No. 63-176535 and examining the practical strength, workability, surface accuracy, and industrial productivity, etc., at least the molding surface of a substrate with high surface accuracy was oxidized. The formation of a coating layer containing chromium as the main component facilitates practical application and has been found to significantly improve the life, and has completed the present invention.

That is, the composite mold for optical component molding of the present invention is:
A composite mold having a coating layer formed on a surface of a base material, wherein at least a molding surface of the composite mold on which a material to be processed is formed is a coating layer having a thickness of 0.1 μm or more and less than 100 μm. It is characterized in that the layer is a single layer or a multilayer containing chromium oxide as a main component.

The base material of the composite mold for molding optical parts of the present invention is made of a material that withstands temperature, pressure, thermal shock, deformation due to repetition of heating and cooling during molding of optical parts, such as Al
₂ O ₃ ceramics, ZrO ₂ ceramics, Cr ₂ O ₃ ceramics, SiC ceramics, Si ₃ N ₄ ceramics, Sialon ceramics, TiC cermet, TiC-TiN cermet, Cr ₃ C ₂ cermet, Al ₂ O ₃ cermet, WC-C
o-based cemented carbide, WC-TiC-Ni-based cemented carbide, high melting point metals such as Cr, Mo, W, Ta, Nb, platinum group metals and alloys containing these as main components, heat-resistant steel, Inconel and Waspaloy, etc. Of super heat-resistant alloys. Among them, Al ₂ O ₃ ceramics or Cr ₂ O ₃ ceramics, in addition to various properties such as heat resistance and strength, can be joined by mutual diffusion with the coating layer and have a similar thermal expansion coefficient. This is particularly preferable since the coating layer and the substrate hardly peel off due to a difference in thermal expansion and have excellent adhesion. In addition, since a cemented carbide is relatively easy to process and easy to finish with high surface accuracy, a thin coating layer is formed by chemical vapor deposition (CVD) or physical vapor deposition (PVD). Is preferred as a base material.

The coating layer to be formed on the surface of these substrates is, for example, specifically composed of chromium oxide of CrO, (mainly Cr ₂ O ₃ ), or mainly composed of chromium oxide, and Cr (C ,
O), Cr (C, N), Cr (C, N, O), which is a single layer or a multilayer containing at least one chromium compound.
This coating layer may have a non-stoichiometric composition or a stoichiometric composition, but is particularly preferably chromium oxide, and when containing other chromium compounds, contains at least 10% by mole of oxygen in the coating layer in a molar ratio. Preferably, the content is at least 50%. Also,
The coating layer contains at least 50 vol% of the above chromium oxide,
Group 4a, 5a, 6a metals (Ti, Zr, Hf, V, Nb, Ta, Cr, M
o, W) oxides, carbides, nitrides, borides, Si, B oxides, nitrides, carbides, Al oxides, nitrides, alkaline earth metals (Be, Mg, Ca, Sr, Ba) ), Rare earth metals (Sc, Y, La, C
e, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) and at least one first substance in a mutual solid solution thereof. This is preferable because a coating layer made of high hardness, dense and fine crystals can be obtained. further,
The coating layer contains at least 50 vol% of the above chromium oxide,
When the balance is composed of the remaining Fe, Co, Ni, Cr, Mn, Mo, Ta, W, Ru, Rh, Pd, Re, Ir, Pt, Au, and at least one of the second materials among these alloys This is preferable because the surface accuracy of the coating layer is improved, the adhesion between the substrate and the coating layer is improved depending on the type of the material of the substrate, and the thermal shock resistance is excellent. This coating layer comprises chromium oxide, the first substance and the second substance.
Chromium oxide may be at least
It is preferable to contain 50 vol%.

Among these coating layers, in the case of the coating layer containing the first substance and / or the second substance, the so-called gradient in which the Cr element in the coating layer gradually decreases from the surface of the coating layer toward the substrate. The use of a coating layer is preferable because the peeling resistance of the coating layer from the base material is improved and the strength of the coating layer is improved.

When the thickness of these coating layers is less than 0.1 μm, the surface of the glass after forming tends to be roughened and the life is shortened. Conversely, when the thickness of the coating layer is 100 μm or more, the particles on the surface of the coating layer are reduced. The growth becomes remarkable, and as a result, the surface accuracy of the coating layer is reduced, and defects such as cracks and pits are increased in the coating layer, so that it becomes difficult to practically use as a molding mold for optical parts. For this reason, the thickness of the coating layer is 0.1 μm or more to 100 μm.
m. In particular, when formed by CVD or PVD, the thickness of the coating layer is preferably from 0.1 to 20 μm, more preferably from 0.5 to 100 μm.

Depending on the combination of the type of the material of the substrate and the type of the material of the coating layer, the adhesion or the adhesion strength between the substrate and the coating layer may be reduced. In this case, an intermediate layer can be interposed between the base material and the coating layer. As the intermediate layer, for example, a metal such as Ni, Co, Cr, Ti, Cu, Ti-Al, Ni-P, N
Alloys such as i-Al, Ti-Ni-Al, Ni-Si, etc., Periodic Table 4a, 5a,
Compounds such as carbides, nitrides, oxides, and mutual solid solutions of Group 6a metals can be given. Among these intermediate layers, it is preferable that the intermediate layer be made of at least one of Cr, Ti, titanium carbide, titanium carbonitride, titanium carbonate, and titanium carbonitride. Particularly, in the case of a cemented carbide substrate, Cr, Ti,
It is preferable that the intermediate layer be made of an intermediate layer of titanium carbide. This intermediate layer is for increasing the adhesive strength between the base material and the coating layer, and is particularly preferably 0.05 to 10 μm in thickness.

In order to produce the composite mold for optical component molding of the present invention, a coating layer can be formed on the above-mentioned base material used conventionally by applying various methods conventionally used. For example, when the coating layer is a thin layer having a thickness of about 0.1 to 30 μm, it is preferable to form the coating layer by a PVD method or a CVD method. The powder can be formed by a method of placing and heating under pressure and a method of thermal spraying or the like.

(Operation) In the composite mold for molding optical parts of the present invention, the coating layer acts to prevent reaction, wetting, and welding with the work material, particularly glass, and as a result, discoloration and surface roughness of the work material are prevented. The base material holds the coating layer and acts to cover the strength of the coating layer.

In the case where an intermediate layer is interposed in the composite mold for molding an optical component of the present invention, the intermediate layer functions to enhance the welding property and adhesion strength between the coating layer and the substrate.

Example A commercially available cemented carbide, 1 μm or less fine alumina-based sintered body was used as a base material, and these base materials were formed into a columnar shape (10φ ×
One end face was ground and polished into a concave spherical surface (radius 15 mm) having a surface roughness of Rmax 0.01 μm or less.

Of these substrates, a cemented carbide substrate was placed in a sputtering apparatus, and a mixed powder or a sintered body having the composition of the coating layer was targeted, and an argon gas pressure of 5 × 10 ⁻³ Torr, RF5
A coating layer was formed on the surface of the substrate by sputtering under the condition of 00 W, to thereby obtain products 1, 2, 3, and 4 of the present invention.

In addition, a cemented carbide substrate was placed in a plasma CVD device,
Chromium carbonyl [Cr (CO) ₆ ] heated to 5 ° C. is introduced into the reaction vessel with a carrier gas of H ₂ gas, and plasma is generated in the reaction vessel by a high-frequency power source, and the pressure is 1.0 T
A coating layer was formed on the surface of the substrate under the conditions of orr, substrate temperature of 350 ° C. and holding for 2 hours, to thereby obtain a product 5 of the present invention.

Next, the base material of the alumina-based sintered body was set in a CVD device,
Zirconium tetrachloride (ZrCl ₄ ) heated to about 200 ° C and 40 ° C
In a reactor in which chromyl chloride (CrO ₂ Cl ₂ ) heated to room temperature was introduced with a carrier gas of Ar-1 vol% H ₂ O, a furnace pressure of 20
A coating layer was formed on the surface of the substrate under the conditions of 0 Torr, a substrate temperature of 850 ° C., and a holding time of 3 hours to obtain a product 6 of the present invention.

In addition, a cemented carbide base material is installed in a CVD system, and Cr (O ₂ C
₅ H ₇₎ 3 _(Kiyariagasu N ₂ -1vol% H ₂ O) in the furnace atmosphere pressure 780 torr, a substrate temperature of 350 ° C., to form a coating layer on the substrate surface under the conditions of 3 hours holding the present invention product 7 I got

Next, the substrate of the alumina-based sintered body was placed in a high-temperature furnace, and Ar gas bubbled in a chromium chloride solution at 40 ° C was introduced into the furnace and held at 1300 ° C for 1 hour to coat the substrate surface. A layer was formed to obtain a product 8 of the present invention.

In addition to the inventive products 1 to 8 thus obtained, a comparative product 1, Al ₂ having a TiC coating layer formed on the substrate surface by a CVD method using a cemented carbide substrate as a comparison. O ₃ coating layer comparative product 2 was formed on the substrate surface, thereby forming an ion plating method with with with TiN coating layer formed comparative product 3 was the coating layer of Pt with at sputtering on the substrate surface Comparative product 4 was obtained.

X-ray diffraction, XMA analysis, and SEM observation of the coating layers of each of the present invention products 1 to 8 and comparative products 1 to 4 show that the component composition and thickness of the coating layer and the presence of the intermediate layer are as follows. , And the components and thicknesses are shown in Table 1.

Using the thus obtained inventive products 1 to 8 and comparative products 1 to 4, a practical test corresponding to the molding of the following glass lens was performed, and the number of moldings determined to be the life at that time was obtained. It was also described in.

Practical test conditions Glass material: Lead glass (equivalent to SF10) Heating temperature: 500 ° C Pressing force: 40 kg Pressing time: 20 seconds Operating atmosphere: N ₂ -1 vol% O ₂ Evaluation: Continuous molding 250 times per cycle Judgment is made based on the surface roughness and releasability of the glass after molding, and if the life is shorter than one cycle, the number of moldings is displayed.

(Effects of the Invention) As described above, the composite mold for molding an optical component of the present invention is less likely to react with glass, adheres to glass, and has excellent releasability, as compared with a composite mold having a conventional coating layer. In addition, the precision of the molding surface of the mold and the precision of the glass surface after the molding process are not easily reduced, and as a result, the service life in practical use is improved by 2 to 100 times. In addition, the composite mold for molding an optical component of the present invention has an effect that it can be practically used even in the air, particularly when it is made of a coating layer of chromium oxide.

Continuation of the front page (56) References JP-A-63-123822 (JP, A) JP-A-2-97431 (JP, A) JP-A-60-118638 (JP, A) JP-A-63-297223 (JP) , A) JP-A-2-26841 (JP, A)

Claims (9)

(57) [Claims] In a composite mold having a coating layer formed on the surface of a base material, at least a molding surface of the composite mold on which a material to be processed is formed of a coating layer having a thickness of 0.1 μm or more and less than 100 μm. And a composite mold for molding optical parts, wherein the coating layer is a single layer or a multilayer containing chromium oxide as a main component. 2. The coating layer according to claim 1, wherein said chromium oxide comprises at least 50 vol%, and oxides, carbides, nitrides, borides, oxides of Si, B of metals belonging to groups 4a, 5a, and 6a of the periodic table. Nitrides, carbides, oxides of Al, nitrides, alkaline earth metals,
The composite mold for optical component molding according to claim 1, comprising an oxide of a rare earth metal and at least one first substance in a mutual solid solution thereof. 3. The coating layer according to claim 1, wherein the chromium oxide contains at least 50 vol% and the remaining Fe, Co, Ni, Cr, Mn, Mo, Ta, W, Ru, Rh, Pd, R
The composite mold for molding an optical component according to claim 1, wherein the composite mold is made of at least one second material selected from e, Ir, Pt, Au and their mutual alloys. 4. The coating layer contains at least 50 vol% of the chromium oxide and oxides, carbides, nitrides, borides, oxides of Si, B of metals belonging to groups 4a, 5a and 6a of the periodic table. Nitrides, carbides, oxides of Al, nitrides, alkaline earth metals,
Rare earth metal oxides and at least one first substance in their mutual solid solution with Fe, Co, Ni, Cr, Mn, Mo, Ta, W, Ru, R
2. The composite mold for molding optical parts according to claim 1, wherein the composite mold comprises at least one second substance selected from the group consisting of h, Pd, Re, Ir, Pt, and Au and their mutual alloys. 5. The composite mold for molding optical parts according to claim 1, wherein said coating layer has a thickness of 0.5 to 10 μm. 6. The coating layer according to claim 1, wherein the Cr element in the coating layer decreases from the surface of the coating layer toward the substrate. Item 7. The composite mold for molding optical parts according to Item 1. 7. A composite mold having a coating layer formed on the surface of a substrate, wherein at least the molding surface of the composite mold on which a workpiece is formed is a coating layer having a thickness of 0.1 μm or more and less than 100 μm. The coating layer comprises a single layer or a plurality of layers mainly containing at least one chromium compound among chromium oxide, chromium oxycarbide, chromium oxynitride, and chromium oxycarbonitride; A composite mold for molding optical components, characterized by having an intermediate layer interposed between the composite mold and the composite mold. 8. The optical component according to claim 7, wherein the intermediate layer is made of at least one of Cr, Ti, titanium carbide, titanium carbonitride, titanium carbonate, and titanium carbonitride. Composite mold for molding. 9. The composite mold for molding optical parts according to claim 7, wherein said intermediate layer has a thickness of 0.05 to 10 μm.