JP4690100B2 - Mold for glass optical element and method for manufacturing glass optical element - Google Patents

Description

  The present invention relates to a mold used for precision mold pressing of glass optical elements such as optical lenses. More specifically, the present invention is excellent in releasability from molding materials and suppresses light scattering and shape defects on the surface of the molded optical element. The present invention relates to a glass optical element mold having a coating film that can be formed. In particular, the present invention relates to a mold having durability against continuous pressing and high production efficiency. Furthermore, this invention relates to the manufacturing method of the glass optical element using the said shaping | molding die.

  Optical elements such as glass lenses are widely used in optical devices such as digital cameras and camera-equipped mobile phones. In particular, an aspherical optical element is useful in order to simultaneously achieve a reduction in size and weight of a lens configuration of an optical device. In order to manufacture aspherical optical elements, the optical polishing method, which is a conventional optical element manufacturing method, is inferior in workability and mass productivity, so the direct press molding method that does not require polishing on the molding surface is mainly applied. Has been. In general, press molding of a glass optical element is performed by applying pressure at a predetermined temperature to a molding material (for example, a glass preform obtained by preforming glass into a predetermined shape) using a molding die that has been processed to a desired accuracy. Done. As a result, the surface shape of the mold is transferred to the surface of the molded body.

  Because optical elements require extremely high surface accuracy, the mold material must have low chemical action on glass at high temperatures, and the molding surface must be resistant to damage such as scratches. It is required to have high resistance to breakage due to thermal shock and to hardly cause fusion with glass. In order to improve the chemical reaction resistance and damage resistance of such a mold, a mold having a molding surface in which a surface of a high-hardness base material such as cemented carbide is coated with a noble metal release film has been proposed.

  For example, Japanese Patent Publication No. 4-16415 (Patent Document 1) discloses a coating film of a noble metal containing a cemented carbide as a base material and an alloy containing at least one of rhenium and osmium in iridium as a main component. Yes.

  Japanese Examined Patent Publication No. 4-81530 (Patent Document 2) contains a thin film mainly composed of an iridium-rhenium alloy containing 30 wt% or more of rhenium, or 40 wt% or more of osmium on the press surface of the molding die. A press mold coated with a thin film mainly composed of an iridium-osmium alloy is disclosed.

  Japanese Patent Application Laid-Open No. 2003-73134 (Patent Document 3) discloses that an amorphous hydrogenation containing one or more metals selected from iridium, rhenium, osmium, palladium, rhodium, ruthenium, gold, platinum, tungsten, and tantalum on the surface. A mold having a carbon coating film is disclosed. In addition, between the coating film and the mold body, one or more metals selected from aluminum, boron, chromium, hafnium, niobium, tantalum, titanium, vanadium, zirconium, metal nitride, metal carbide, metal boride, or It is disclosed to provide an intermediate layer formed from a metal carbonitride.

  Japanese Patent Application Laid-Open No. 2004-189565 (Patent Document 4) includes a coating layer containing any one of chromium, nickel, or an alloy of chromium and nickel as a first component and iridium as a second component, or this Further, a mold having a coating layer made of platinum and rhenium or an alloy of platinum and rhodium is disclosed as a third component.

In Japanese Patent Publication No. 6-88803 (Patent Document 5), a cemented carbide mainly composed of tungsten carbide is used as a base material, and iridium is 10 to 70 wt%, rhenium is 10 to 70 wt%, carbon is 20 to A mold for forming a coating film containing a compound composed of 50 wt% as a main component is disclosed.
Japanese Patent Publication No. 4-16415 Japanese Patent Publication No. 4-81530 JP 2003-73134 A JP 2004-189565 A Japanese Patent Publication No. 6-88803

  However, the molds described in Patent Documents 1 to 4 have the advantage that the chemical reactivity with glass is relatively low, but because of their high adhesion to glass, the purpose is to shorten the molding tact after press molding. Thus, it is difficult to release the molded body at a relatively high temperature. In addition, during the continuous pressing, there is a problem that the glass molded body firmly adheres to the molding surface of the mold and cannot be removed, or that the release film peels off when the molded body is removed. For this reason, it cannot prevent that the glass and the molding surface are fused at the time of press molding or the glass molded body is cracked from the peeled portion of the release film.

  The release film described in Patent Document 5 exhibits high oxidation resistance, heat resistance, and alkali resistance, but is an optical glass having a high softening point and an optical glass containing a highly reactive composition component (for example, phosphoric acid-based optics). Glass), when press-molding a glass material made of highly refractive and highly dispersed optical glass containing components (W, Nb, Ti, etc.) that are easily reduced, a reaction is likely to occur at the interface between the mold and the glass. As a result, there is a possibility that the glass is fused to the surface of the mold, and further, the surface of the molded body is damaged by the fused product. Therefore, the mold described in Patent Document 5 is not suitable for pressing a glass material pressed at a high temperature or a glass material made of highly reactive glass.

  Under such circumstances, the present invention was made for the purpose of providing a means for enabling high-precision glass optical elements having excellent optical performance to be manufactured with high production efficiency by a precision mold press. Is.

The above object of the present invention has been achieved by the following means.
[1] A mold for a glass optical element having a coating film on a molding surface,
The coating film is
As the first component, at least one selected from the group consisting of iridium (Ir), platinum (Pt), palladium (Pd), rhodium (Rh), ruthenium (Ru), osmium (Os), and rhenium (Re), and ,
Contains at least one selected from the group consisting of manganese (Mn), cobalt (Co), copper (Cu), titanium (Ti), vanadium (V), niobium (Nb), and zirconium (Zr) as the second component And
In the first component, iridium is an essential component contained as the most abundant component, and
A mold for glass optical elements , wherein manganese is an essential component in the second component .
[2] The mold for a glass optical element according to [1], wherein the iridium content in the coating film is in the range of 30 to 90% by mass and the manganese content is in the range of 5 to 50% by mass.
[3] The glass optical element molding according to [1] or [2], wherein the iridium content in the coating film is in the range of 40 to 70% by mass and the manganese content is in the range of 10 to 50% by mass. Type.
[ 4 ] The mold for glass optical element according to any one of [1] to [3], wherein the content of the first component in the coating film is in the range of 40 to 99% by mass.
[ 5 ] The glass optical element mold according to any one of [1] to [4], wherein the content of the second component in the coating film is in the range of 1 to 60% by mass.
[ 6 ] Between the mold base material of the mold and the coating film, chromium (Cr), manganese (Mn), nickel (Ni), cobalt (Co), copper (Cu), titanium (Ti), vanadium ( Any one of [1] to [ 5 ], comprising a first intermediate layer containing at least one selected from the group consisting of V), niobium (Nb), zirconium (Zr), and tantalum (Ta) The mold for glass optical elements as described in 2.
[ 7 ] Between the mold base of the mold and the first intermediate layer, aluminum (Al), boron (B), manganese (Mn), chromium (Cr), cobalt (Co), copper (Cu), At least one metal selected from the group consisting of nickel (Ni), hafnium (Hf), niobium (Nb), tantalum (Ta), titanium (Ti), vanadium (V), and zirconium (Zr), nitriding of the metal The glass optical element mold according to [ 6 ], comprising a second intermediate layer containing at least one selected from the group consisting of a material and / or a carbide, and nickel phosphorus (Ni-P).
[ 8 ] The second intermediate layer is at least one selected from the group consisting of titanium nitride (TiN), aluminum nitride (AlN), chromium nitride (CrN), boron nitride (BN), and nickel phosphorus (Ni-P). The glass optical element molding die according to [ 7 ], comprising:
[ 9 ] The glass optical element mold according to any one of [1] to [ 8 ], wherein the mold base material of the mold contains tungsten carbide or silicon carbide.
[ 10 ] Production of a glass optical element, wherein a glass molding material having a carbon-containing film on its surface is press-molded using the glass optical element molding die according to any one of [1] to [ 9 ]. Method.
[ 11 ] The glass molding material is an optical glass containing 20% by mass or more in total of at least one selected from the group consisting of titanium (Ti), tungsten (W), niobium (Nb), and bismuth (Bi), [ 10 ] The method for producing a glass optical element according to [ 10 ], comprising optical glass containing 20% by mass or more of phosphate or optical glass containing 5% by mass or more of fluorine.

The molding die for glass optical element of the present invention has a coating film that does not peel off and has excellent durability on its molding surface. According to the glass optical element molding die of the present invention, continuous pressing can be performed many times without causing defects such as fusion and cracking on the surface of the optical element to be molded, and the production efficiency and accuracy of the optical element can be achieved. Both (yield) can be kept high.
In addition, in order to obtain specific optical performance, it is possible to obtain high surface accuracy by suppressing fusion between the optical mold and surface flaws caused by reaction even for optical glass having a highly reactive composition. It becomes possible.

Hereinafter, the present invention will be described in more detail.

[Glass optical element mold]
The mold for glass optical element of the present invention is
A molding die for a glass optical element having a coating film on a molding surface,
The coating film is
As the first component, at least one selected from the group consisting of iridium (Ir), platinum (Pt), palladium (Pd), rhodium (Rh), ruthenium (Ru), osmium (Os), and rhenium (Re), and ,
Contains at least one selected from the group consisting of manganese (Mn), cobalt (Co), copper (Cu), titanium (Ti), vanadium (V), niobium (Nb), and zirconium (Zr) as the second component This is a glass optical element molding die.

The molding die of the present invention has a coating film containing the first component and the second component. The first component (hereinafter also referred to as a noble metal component) has extremely low reactivity with glass, and can impart high mold releasability to the mold. Further, the introduction of the second component significantly improves the adhesion between the coating film and the mold base material. Thereby, even if it press-molds many times continuously, generation | occurrence | production of the fusion | melting of glass and a mold | die by peeling of a coating film, or the crack of an optical element resulting from it can be reduced significantly.
Further, even when the coating film is press-molded with high-reactivity glass or used at a high temperature with high reactivity, reaction at the interface hardly occurs, and surface flaws due to fusion or reaction can be suppressed. That is, it has excellent oxidation resistance, which is very important in the molding of glass optical elements, and is inert to glass. Moreover, since the mold can be released at a high temperature, production with a short tact time can be realized.

Coating Film The coating film includes, as a first component (noble metal component), iridium (Ir), platinum (Pt), palladium (Pd), rhodium (Rh), ruthenium (Ru), osmium (Os), and rhenium (Re At least one selected from the group consisting of: As the first component, gold (Au) can be further contained.

  The first component has the effect of improving the mold release properties of the glass molding material and the coating film. However, if introduced excessively, the adhesion between the coating film and the mold base material and the intermediate layer described later may be insufficient, and the coating film may be easily peeled off. On the other hand, if the content of the first component is too small, the coating film and the molded optical element are likely to be fused. From the above viewpoint, it is preferable that the content of the first component in the coating film (in the case of including plural types, the total amount thereof) is 40 to 99% by mass. More preferably, it is 45-95 mass%.

Examples of the first component contained in the coating film include the following components.
(1) Iridium, rhodium (2) Iridium, rhenium (3) Iridium, osmium,
(4) Iridium, platinum, rhodium (5) Iridium, rhenium, rhodium (6) Iridium, osmium, rhodium (7) Iridium, platinum (8) Iridium alone

The coating film preferably contains iridium as a first component, and more preferably contains iridium alone or a combination of iridium and osmium or platinum.
In the first component, for example, it is preferable to apply iridium as the most abundant component, and it is preferable to set it to 50 mass% or more of the first component.

  The coating film is selected from the group consisting of manganese (Mn), cobalt (Co), copper (Cu), titanium (Ti), vanadium (V), niobium (Nb), and zirconium (Zr) together with the first component. A second component (hereinafter also referred to as a transition metal component). The second component may further contain chromium (Cr), tantalum (Ta) and / or nickel (Ni).

  The second component has the effect of increasing the adhesion between the coating film and the mold base material. That is, the introduction of these components plays a major role in preventing the coating film from peeling off and preventing the glass and the mold from fusing together. The introduction amount (the total amount when plural types are included) is preferably 1% by mass or more in order to obtain sufficient adhesion to the mold base material. In addition, if the introduction amount of the second component is excessively large, these components may directly react with the glass and become liable to be fused, so that the introduction amount is 60% by mass or less. Is preferred. The content of the second component in the coating film is more preferably in the range of 5 to 55% by mass.

Examples of the second component contained in the coating film include the following components.
(1) Manganese alone (2) Manganese, Chromium (3) Manganese, Nickel (4) Manganese, Cobalt (5) Manganese, Chromium, Nickel (6) Manganese, Chromium, Cobalt (7) Manganese, Chromium, Titanium (8) Manganese, nickel, cobalt (9) manganese, nickel, titanium (10) manganese, cobalt, titanium (11) manganese, chromium, nickel, titanium (12) manganese, chromium, cobalt, titanium (13) manganese, nickel, cobalt, titanium

  The coating film preferably contains manganese as the second component, (a) manganese and chromium or nickel, (b) a combination of manganese, chromium and nickel, or (c) the above (a) or (b It is more preferable that the combination of any one of these and cobalt is included.

  The content of the first component and the second component in the coating film is preferably determined within a range in which both the reactivity with the glass to be press-molded and the difficulty of peeling are compatible, and the content of the first component is the second component. More than the content is preferred.

The following can be illustrated as a preferable composition of the said coating film.
(A) 30-90 mass% of iridium which is a 1st component is contained in the component of a coating film.
(B) It is (A) and contains at least one of platinum, rhenium, osnium and rhodium as the other first component in a total amount of 5 to 40% by mass.
(C) Manganese which is the second component is contained as a coating film component in an amount of 5 to 50% by mass.
(D) It is (C), and contains 5 to 40% by mass of the coating film component as a total amount of any one of chromium, nickel, cobalt, and titanium as the other second component.

  The coating film may be an alloy film composed of the first component and the second component described above, and an alloy containing the first component and the second component in a proportion corresponding to the composition of the coating film to be formed is used. Thus, it can be formed by a known film formation method. Examples of the film forming method include a sputtering method, a vacuum deposition method, and an ion plating method. The thickness of the coating film can be, for example, 10 to 3000 nm, preferably 20 to 2000 nm, and more preferably 20 to 1000 nm. By adjusting the film forming conditions, a coating film having a desired film thickness can be formed. In addition, a known surface treatment such as mirror polishing can be applied to the molding surface before film formation.

Intermediate layer The mold according to the present invention has a chromium (Cr), manganese (Mn), nickel (Ni), between the mold base material and the coating film in order to improve the adhesion between the mold and the coating film. An intermediate layer containing at least one selected from the group consisting of cobalt (Co), copper (Cu), titanium (Ti), vanadium (V), niobium (Nb), zirconium (Zr), and tantalum (Ta) One intermediate layer). As a component contained in the first intermediate layer, the component of the first intermediate layer and its adjacent portion, for example, a component that easily reacts with the component that constitutes the mold base material and the component that constitutes the coating film, is selected. The adhesion between the base material and the coating film can be greatly increased. Due to the presence of this layer, peeling of the coating film during continuous press molding at a high temperature can be more effectively suppressed.

  The first intermediate layer preferably contains a component common to at least one of the second components (transition metal components) described above. For example, when the coating film contains Mn, it is effective to contain a predetermined amount of Mn in the first intermediate layer.

  Moreover, when the first intermediate layer is formed directly on the mold base material, the components in the first intermediate layer can be selected in consideration of the composition of the mold base material. Specifically, a component common to the component contained in the mold base material can be selected as the transition metal component in the first intermediate layer. For example, when a component such as Co or Ni is introduced into the mold material (or when it is present as an impurity), it is recommended that Co or Ni be contained in the first intermediate layer. When a predetermined component common to the first intermediate layer is introduced into the mold base material, the content thereof is about 0.001 to 2% by mass with respect to the main component of the mold base material. It is preferable that the strength and rigidity are not affected.

  Furthermore, the mold of the present invention includes aluminum (Al), boron (B), manganese (Mn), chromium (Cr), cobalt (Co), between the mold base material and the first intermediate layer. At least one metal selected from the group consisting of copper (Cu), nickel (Ni), hafnium (Hf), niobium (Nb), tantalum (Ta), titanium (Ti), vanadium (V), and zirconium (Zr) And an intermediate layer (second intermediate layer) containing at least one selected from the group consisting of nitrides and / or carbides of the metal and nickel phosphorus (Ni-P). The second intermediate layer can enhance the oxidation resistance of the mold base material and can greatly increase the adhesion with the first intermediate layer. Thereby, a mold base material and a coating film do not peel, and the life of the coating film at the time of high-temperature press molding can be further extended.

  The second intermediate layer also has a function of an antioxidant film of the mold base material. The second intermediate layer is made of a nitride or carbide containing any of Al, B, Cr, Co, Cu, Ni, Ti, V, Nb, Zr, or Ta, or nickel phosphorus (Ni-P). It is preferable that at least one selected from the group is contained. In this case, the presence of a nitride, carbide or nickel phosphorus containing a component common to the component of the first intermediate layer is preferred. Thereby, adhesiveness with a 1st intermediate | middle layer becomes higher, As a result, the adhesiveness of a 1st intermediate | middle layer and a coating film, and a type | mold base material can further be improved. In addition, the above-described metals, metal nitrides, metal carbides, and nickel phosphorus have high strength, hardness, and oxidation resistance, and are suitable as intermediate layers. In particular, in the present invention, the second intermediate layer is selected from the group consisting of titanium nitride (TiN), aluminum nitride (AlN), chromium nitride (CrN), boron nitride (BN), and nickel phosphorus (Ni-P). It is preferable to contain at least one kind.

  The film thickness of the first intermediate layer can be appropriately set in consideration of the adhesion between the mold base material and the coating film, and can be set to, for example, 10 to 500 nm, preferably 10 to 200 nm. The first intermediate layer can be formed with a substantially uniform thickness on the molding surface of the mold base or the second intermediate layer. The first intermediate layer can be formed by a known method such as sputtering or vacuum evaporation.

  The film thickness of the second intermediate layer can be appropriately set in consideration of the adhesion between the mold base material and the first intermediate layer, for example, 20 nm to 2 μm, preferably 300 nm to 1.5 μm. can do. The second intermediate layer can be formed on the molding surface of the mold base material with a substantially uniform thickness. A known film forming method such as an ion plating method can also be used when forming the second intermediate layer. Note that Ni—P can be formed by plating, which is simple.

Mold Base The mold according to the present invention is heat-resistant, and preferably has the above-described coating film and, if necessary, an intermediate layer formed on a high hardness mold base. The mold base material is preferably a cemented carbide mainly composed of tungsten carbide (WC), which is a dense material having high thermal conductivity, or silicon carbide (SiC). In particular, WC, which is a cemented carbide, is characterized by excellent workability, although its oxidation resistance is inferior to that of SiC. Although SiC has very high hardness and inferior workability, it is characterized by excellent oxidation resistance and long life. The mold base material can be appropriately selected depending on the number of production lots and the type of glass. In the present invention, tungsten carbide is more preferable. In this case, a high-purity material that substantially does not contain impurities such as a binder may be used, or a material that contains a component such as Co may be used. In particular, the latter case can be suitably used by appropriately selecting the composition of the first or second intermediate layer as described above. In addition, as described above, it is extremely effective to provide the second intermediate layer on the WC type surface in order to compensate for the drawback of being weak in oxidation resistance of WC.
By subjecting the mold base as described above to precision processing such as grinding and polishing based on the shape of the desired optical element, the shape of the molding surface can be made desired.

Glass molding material There is no particular limitation on the composition of the optical glass for press molding using the molding die of the present invention. However, the molding die of the present invention has the advantage of preventing fusion and cracking even when it is press-molded using highly chemically reactive glass, and can withstand, for example, thousands of continuous presses. It can be particularly effective when applied to press molding of seed glass. For example, those containing at least one selected from the group consisting of Ti, W, Nb and Bi, which are easily reduced components, in a total amount of 20% by mass or more, or containing 20% by mass or more of phosphate as a glass skeleton component Or a fluorophosphate glass containing a large amount of a low softening point component (for example, containing 5% by mass or more of fluorine).

In particular, glass compositions suitable for application of the mold of the present invention are shown below.
(1) As an essential component, it contains P ₂ O ₅ , Nb ₂ O ₅ , WO ₃ , TiO ₂ , Bi ₂ O ₃ , Li ₂ O, Na ₂ O, Nb ₂ O ₅ , WO ₃ , TiO ₂ , The total amount of Bi ₂ O ₃ is 25 to 45 mol%;
(2) A (1), and those P ₂ O ₅ is 16 to 30 mole%;
(3) The above (1) or (2), wherein the refractive index nd is 1.75 to 2.0 and the Abbe number νd is 18 to 30;
(4) Including P ₂ O ₅ , SiO ₂ , and an alkali metal oxide as essential components, having a refractive index nd of 1.8 or more and an Abbe number νd of 30 or less;
(5) As an essential component, P ⁵⁺ , Al ³⁺ , a divalent component (Mg ²⁺ , Ca ²⁺ , Sr ²⁺ , Ba ²⁺ ), Li ⁺ , F ⁻ Fluoric acid-based optical glass containing 0.5 or more in a molar ratio of (F + O);
(6) The above (5), wherein the refractive index nd is 1.55 or less and the Abbe number νd is 75 or more.
(7) as an essential component, the P ₂ O _5, 25 mol% or more, BaO 20 mol% or _{more, Li 2 O, Na 2 OK} 2 O any of those containing 3 mol% or more as a total amount.
(8) The above (7), wherein the refractive index nd is 1.55 to 1.72 and the Abbe number νd is 57 to 70.

  In particular, when high-refractive index and high-dispersion optical glass such as (1) to (4) above is precision press-molded, if a conventional molding die is used, the lens surface after molding is circular from the center. There is a tendency that linear scars (hereinafter referred to as radiation scratches) are generated in the circumferential direction. An outline of the radiation scratches is shown in FIG. This is thought to damage the surface of the glass that is deformed by stretching from the center to the periphery in a state where the product adheres to the mold surface as a result of the reaction occurring at the interface between the glass and the molding surface. When the mold of the present invention is used, this tendency is effectively suppressed, and the yield of the optical element can be remarkably improved.

  The coating film of the mold of the present invention can greatly improve the adhesion with the mold base material as compared with the conventional coating film. On the other hand, depending on the transition metal component contained, depending on the composition of the glass material to be molded, the chemistry with glass may be slightly increased. However, even in such a case, the chemical reaction between the mold and the glass can be suppressed by providing a specific film on the surface of the glass molding material. That is, in the present invention, a glass molding material having a film containing carbon, preferably a film containing carbon as a main component, on the surface can be used. The carbon-containing film can be formed with a thickness of 0.5 to 10 nm, for example. This film can be formed by vapor deposition using mainly carbon as a raw material, sputtering, thermal decomposition CVD using hydrocarbons, plasma decomposition, chemical vapor deposition, or the like. The carbon-containing film not only prevents the reaction between the glass and the mold, but also can remarkably reduce the frictional force between the glass molded body and the coating film, thereby further improving the releasability of the glass molded body. It also has the effect.

  The glass molding material can be obtained by a known method. In the present invention, it is preferable to use a glass forming material preliminarily molded into a predetermined volume. For example, it is possible to use a glass molding material obtained by cold working optical glass solidified after melting into a predetermined volume by cutting and polishing. More preferably, in the present invention, a molten optical glass that is dripped or flowed down into a receiving mold and preformed into a predetermined volume of a spherical shape or a biconvex curved shape can be suitably used. After cooling and solidifying this, it is preferable to apply the above carbon-containing film.

Press molding method When performing press molding using the mold of the present invention, a known press molding method can be applied. For example, in an inert gas atmosphere or under vacuum, the glass molding material is heated to a temperature equal to or higher than its softening temperature, and pressure-molded by applying a predetermined load in the softened state. The glass molding material is heated to a viscosity of about 10 ⁶ to 10 ⁹ dPa · s, and then supplied to a molding die at a lower temperature (for example, a glass material viscosity equivalent to 10 ⁸ to 10 ¹¹ dPa · s). Or after supplying a glass raw material to a shaping | molding die, you may heat to about ¹⁰ < ⁷ > -10 < ¹⁰ > dPa * s. After transferring the shape of the molding surface to the glass molding material by pressing, cool down to near the glass transition temperature (Tg) while maintaining close contact between the molding surface of the glass and the mold, and then release and remove the molded product. Can do.

Hereinafter, the present invention will be described in more detail with reference to examples.

[Example 1-13, Comparative Example 1]
Using a cylindrical cemented carbide (WC) having a diameter of 20 mm, a press mold for a pair of glass lenses consisting of an upper and lower mold having a concave molding surface with a curvature of 12 mm was processed. The molding surface was mirror-polished using diamond abrasive grains of 1 μm or less. Next, a noble metal film (coating film) containing a transition metal component was formed on the mirror surface by sputtering. The ultimate vacuum of the sputtering apparatus was 1.3 × 10 ⁻⁴ Pa and the RF magnetron method was used. The target size was φ50.8 mm and the sample target distance was 150 mm. The film formation conditions were an argon gas flow rate of 20 sccm, an argon gas pressure during sputtering of 0.33 Pa, a voltage of 0.2 W / mm ² , and a necessary film formation time. In this example, the thickness of the coating film was 300 nm.
A schematic cross-sectional view of this mold is shown in FIG.

As a glass material, a high refractive index, high dispersion phosphoric acid optical glass A (composition is expressed as mol% 22P ₂ O ₅ -19Nb ₂ O ₅ -8WO ₃ -5TiO ₂ -4Bi ₂ O ₃ -20Li ₂ O-11Na) ₂ O-2K ₂ O-4B ₂ O ₃ -3BaO-2ZnO, thermal properties are transition temperature Tg = 454 ° C., yield temperature Ts = 508 ° C., optical constants are nd = 1.87427, νd = 22.37) was used. This was used as a glass forming material (glass preform) obtained by pre-flowing from a glass melt into a receiving mold and preforming it into a biconvex curved shape.

  FIG. 5 shows a schematic diagram of an apparatus used for the press molding test. A glass molding material preformed as described above was placed on the lower mold of this apparatus. First, the chamber was evacuated and then filled with nitrogen at 10 L / min. Then, while injecting nitrogen at a rate of 10 L / min, the press mold and the glass molding material were heated to the yield point temperature Ts + 50 ° C. and a load of 3500 N Then, after the pressing, the glass and the mold were kept in close contact with each other and cooled to a temperature of 250 ° C. or lower, and the molded body (optical lens) was taken out.

Using each coating film having the composition shown in Table 1, the occurrence of fusion of the molding surface of the mold and the deterioration of the coating film when the press molding was performed 3000 times were visually evaluated. The results are shown in Table 1.
Table 1 also shows the press results (Comparative Example 1) using a metal coating film containing only the noble metal component and not containing the second component. From this result, when a coating film not containing the second component is used, the coating film is easily peeled off at the initial stage of continuous pressing, and it is not possible to mass-produce lenses with high surface accuracy by repeating press molding. Recognize.

[Examples 14-26]
Using the same mold base material as in Example 1, a first intermediate layer made of a transition metal alloy was formed on a mirror-polished molding surface, and a coating film (a noble metal film containing a transition metal component) was formed thereon. . Table 2 shows the compositions of the first intermediate layer and the coating film. A schematic cross-sectional view of this mold is shown in FIG.

As in Example 1, the coating film and the first intermediate layer were formed by sputtering. For film formation, the same apparatus and method as those used for forming the coating film in Example 1 were used. The ultimate vacuum of the apparatus is 1.3 × 10 ⁻⁴ Pa, the RF magnetron method, the target size is φ50.8 mm, and the sample target distance is 150 mm. The film formation conditions for each film were an argon gas flow rate of 20 sccm, an argon gas pressure during sputtering of 0.33 Pa, and a voltage of 0.2 W / mm ^2, and a film formation time required for each film thickness was given. In this example, the thickness of the coating film was 300 nm, and the thickness of the first intermediate layer was 50 nm.

  Using the same glass forming material as in Example 1, using the apparatus of FIG. 5, 3000 continuous press evaluations were performed as described above. The results are shown in Table 2. The mold in which the coating film was laminated on the first intermediate layer showed no film peeling and the result of continuous pressing was good.

[Examples 27-35]
A second intermediate layer made of TiN or AlN and a first intermediate layer made of a transition metal such as Mn, Cr, Ni are formed on the surface of the molding die base material similar to that in Example 1, and further A coating film (a noble metal film containing a transition metal component) was formed thereon. Table 3 shows the compositions of the first intermediate layer, the second intermediate layer, and the coating film. In this embodiment, transition metal nitride (TiN, AlN) is used for the second intermediate layer, but the present invention is not limited to this. A schematic cross-sectional view of this mold is shown in FIG.

The first and second intermediate layers and the coating film were formed using the sputtering method in the same manner as in Example 1. For film formation, the same apparatus and method as those used for forming the coating film in Example 1 were used. The ultimate vacuum of the apparatus is 1.3 × 10 ⁻⁴ Pa, the RF magnetron method, the target size is φ50.8 mm, and the sample target distance is 150 mm. The film formation conditions for each film were an argon gas flow rate of 20 sccm, an argon gas pressure during sputtering of 0.33 Pa, and a voltage of 0.2 W / mm ^2, and a film formation time required for each film thickness was given. In this embodiment, the coating film has a thickness of 300 nm, the first intermediate layer has a thickness of 50 nm, and the second intermediate layer has a thickness of 1 μm.

  Using the same glass forming material as in Example 1, the continuous press was evaluated 3000 times as described above using the apparatus shown in FIG. The results are shown in Table 3. The mold in which the coating films were laminated on the first and second intermediate layers showed no film peeling and the result of continuous pressing was good.

[Examples 36-45]
Using the same method as in Example 14, a continuous press test similar to that described above was performed using a mold having a first intermediate layer and a coating film having the composition shown in Table 4. Using the same glass molding material as in Example 1, a carbon-containing film was formed on the surface of the glass molding material. Table 4 shows the thickness of the carbon-containing film. The carbon-containing film on the surface of the glass molding material was formed by a CVD method by thermal decomposition of hydrocarbon (acetylene). FIG. 4 shows a schematic cross-sectional view of the mold and the glass molding material. Table 4 shows the evaluation of 3000 continuous presses. In any of the samples, no film peeling or fusion was observed, and the results were good.

  The glass optical element molding die and the glass optical element manufacturing method of the present invention are suitable for press molding optical glass having a highly reactive composition.

The cross-sectional schematic diagram of the shaping | molding die which has a coating film on a shaping | molding surface is shown. The cross-sectional schematic diagram of the shaping | molding die which has a 1st intermediate | middle layer and a coating film in this order on a shaping | molding surface is shown. The cross-sectional schematic diagram of the shaping | molding die which has a 2nd intermediate | middle layer, a 1st intermediate | middle layer, and a coating film in this order on a shaping | molding surface is shown. The cross-sectional schematic diagram of the shaping | molding die in Example 36-45 and a glass forming raw material is shown. The schematic of the apparatus used for the press molding test in an Example is shown. An outline of radiation scratches is shown.

Claims (11)

A molding die for a glass optical element having a coating film on a molding surface,
The coating film is
As the first component, at least one selected from the group consisting of iridium (Ir), platinum (Pt), palladium (Pd), rhodium (Rh), ruthenium (Ru), osmium (Os), and rhenium (Re), and ,
Contains at least one selected from the group consisting of manganese (Mn), cobalt (Co), copper (Cu), titanium (Ti), vanadium (V), niobium (Nb), and zirconium (Zr) as the second component And
In the first component, iridium is an essential component contained as the most abundant component, and
A mold for glass optical elements , wherein manganese is an essential component in the second component . 2. The mold for a glass optical element according to claim 1, wherein the iridium content in the coating film is in the range of 30 to 90 mass% and the manganese content is in the range of 5 to 50 mass%. The mold for glass optical elements according to claim 1 or 2, wherein the iridium content in the coating film is in the range of 40 to 70 mass%, and the manganese content is in the range of 10 to 50 mass%. The glass optical element mold according to any one of claims 1 to 3, wherein the content of the first component in the coating film is in the range of 40 to 99 mass%. The glass optical element molding die according to any one of claims 1 to 4, wherein the content of the second component in the coating film is in the range of 1 to 60 mass%. Between the mold base material and the coating film of the mold, chromium (Cr), manganese (Mn), nickel (Ni), cobalt (Co), copper (Cu), titanium (Ti), vanadium (V), It has a 1st intermediate | middle layer containing at least 1 type chosen from the group which consists of niobium (Nb), a zirconium (Zr), and a tantalum (Ta), It is any one of Claims 1-5 characterized by the above-mentioned. Mold for glass optical elements. Between the mold base material of the mold and the first intermediate layer, aluminum (Al), boron (B), manganese (Mn), chromium (Cr), cobalt (Co), copper (Cu), nickel (Ni ), Hafnium (Hf), niobium (Nb), tantalum (Ta), titanium (Ti), vanadium (V), and zirconium (Zr), at least one metal selected from the group consisting of: Or it has a 2nd intermediate | middle layer containing at least 1 type chosen from the group which consists of carbide and nickel phosphorus (Ni-P), The shaping | molding die for glass optical elements of Claim 6 characterized by the above-mentioned. The second intermediate layer contains at least one selected from the group consisting of titanium nitride (TiN), aluminum nitride (AlN), chromium nitride (CrN), boron nitride (BN), and nickel phosphorous (Ni-P). The mold for glass optical elements according to claim 7 . The mold base for a glass optical element according to any one of claims 1 to 8 , wherein the mold base material of the mold includes tungsten carbide or silicon carbide. A method for producing a glass optical element, comprising: press-molding a glass molding material having a carbon-containing film on the surface using the glass optical element molding die according to any one of claims 1 to 9 . The glass molding material is an optical glass or phosphate containing a total amount of at least one selected from the group consisting of titanium (Ti), tungsten (W), niobium (Nb), and bismuth (Bi) in an amount of 20% by mass or more. 11. The method for producing a glass optical element according to claim 10 , wherein the glass optical element contains 20% by mass or more of optical glass or optical glass containing 5% by mass or more of fluorine.