JP5603125B2 - Mold, manufacturing method thereof, and optical element and optical device manufacturing method - Google Patents

Description

  The present invention relates to a mold and a method for manufacturing the same, and a method for manufacturing an optical element and an optical apparatus.

  Conventionally, a glass molded body has been manufactured by polishing glass cut out from plate glass, polishing it into a shape approximate to a glass molded body, and heat-molding the polished product. However, when producing an optical element such as a lens, this method increases the polishing cost of the glass material. Therefore, a method of forming an optical element such as a lens by press-molding the raw glass using a mold is used.

  Here, for the purpose of reducing the reactivity of the mold used for press molding with the optical glass or increasing the durability of the surface of the mold, a mold having a protective film on the molding surface is known. Yes. For example, a mold having a protective film containing one or more elements selected from the group consisting of Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu is disclosed. (See Patent Document 1). Further, a mold having an intermediate layer containing at least one selected from the group consisting of Zr, Ti, V, Cr, Mo, Nb, Pd and Au is disclosed between the protective film and the mold. (See Patent Document 2).

JP 2009-46320 A JP 2007-269511 A

  However, when lanthanum-based glass is press-molded using the molds disclosed in Patent Documents 1 and 2, the molded glass is likely to be cracked or cloudy. Glass that is cracked or cloudy can no longer be used as an optical element. In addition, when the glass is cracked, it is necessary to remove glass fragments remaining in the mold from the mold.

  The present invention has been made in view of the above problems, and the object of the present invention is, in particular, when forming a lanthanum-based glass, a molding die that hardly causes cracking or clouding in the molded glass, and a method for manufacturing the same. Is to provide.

  As a result of intensive studies and studies to solve the above-mentioned problems, the inventors of the present invention have made the molding by setting the ratio of the Ir and Re contents of the protective film provided on the molding surface of the molding die within a predetermined range. As a result, it was found that cracking and fogging are less likely to occur in the formed glass, and the present invention has been completed.

  (1) A mold comprising a mold base material having a molding surface and a protective film provided on the molding surface, wherein the protective film has Ir and Re content of Ir relative to Ir content. The mold is contained in such a content that the molar ratio is 2.5 times or less, and the mold is a mold used for molding lanthanum-based glass.

  (2) The mold according to (1), wherein the molar ratio of the Re content to the Ir content is 0.5 times or more.

  (3) The mold according to (1) or (2), wherein the protective film does not substantially contain Rh.

  (4) A lanthanum-based glass having a step of forming a protective film containing Ir and Re in such a content that the molar ratio of the Re content to the Ir content is 2.5 times or less on the molding surface of the mold base material A manufacturing method of a mold used for molding.

  (5) The method for producing a mold according to (4), wherein the molar ratio of the Re content to the Ir content is 0.5 times or more.

  (6) The method for producing a molding die according to (4) or (5), wherein Rh is not substantially contained in the protective film.

  (7) A method for producing an optical element comprising a step of press-molding lanthanum-based glass using the molding die according to any one of (1) to (3).

(8) As the lanthanum-based glass, one or more selected from the group consisting of B ₂ O ₃ component, La ₂ O ₃ component and ZnO component, Nb ₂ O ₅ component, Ta ₂ O ₅ component and WO ₃ component (7) The manufacturing method of the optical element as described in (7) using what contains.

(9) As the lanthanum-based glass, the refractive index (nd) has an optical constant in the range of 1.75 to 1.85 and the Abbe number (νd) in the range of 35 to 45;
SiO ₂ component 0-20%
B ₂ O ₃ component 10-30%
La ₂ O ₃ component 15-40%
ZrO ₂ component 0-15%
Nb ₂ O ₅ component 0-20%
Ta ₂ O ₅ component 0-20%
WO ₃ component 0-20%
ZnO component 10-30%
Li ₂ O component 0-5%
The transition point (Tg) is 500 to 590 ° C., the yield point (At) is 530 to 630 ° C., and no devitrification is observed in the devitrification test at 950 ° C. for 2 hours. (8) The manufacturing method of the optical element described in (8).

  (10) A method for producing an optical instrument using an optical element obtained by press-molding lanthanum-based glass using the molding die according to any one of (1) to (3).

(11) As the lanthanum-based glass, one or more selected from the group consisting of B ₂ O ₃ component, La ₂ O ₃ component and ZnO component, Nb ₂ O ₅ component, Ta ₂ O ₅ component and WO ₃ component (10) The manufacturing method of the optical instrument as described in (10) using what contains.

(12) As the lanthanum-based glass, the refractive index (nd) has an optical constant in the range of 1.75 to 1.85 and the Abbe number (νd) in the range of 35 to 45;
SiO ₂ component 0-20%
B ₂ O ₃ component 10-30%
La ₂ O ₃ component 15-40%
ZrO ₂ component 0-15%
Nb ₂ O ₅ component 0-20%
Ta ₂ O ₅ component 0-20%
WO ₃ component 0-20%
ZnO component 10-30%
Li ₂ O component 0-5%
The transition point (Tg) is 500 to 590 ° C., the yield point (At) is 530 to 630 ° C., and no devitrification is observed in the devitrification test at 950 ° C. for 2 hours. (11) The manufacturing method of the optical instrument which uses a thing.

  According to the present invention, when the ratio of the Ir and Re contents of the protective film provided on the molding surface of the mold is within a predetermined range, particularly when the lanthanum glass is molded, the molded glass is cracked. It is possible to provide a mold that hardly causes scratches or clouding and a method for producing the same.

It is sectional drawing of the shaping | molding die which concerns on one Embodiment of this invention.

  The molding die of the present invention is a molding die comprising a mold base material having a molding surface and a protective film provided on the molding surface, wherein the protective film has Ir and Re as to the Ir content. The Re is contained in such a content that the molar ratio of the Re content is 2.5 times or less, and the mold is used for molding lanthanum-based glass.

  Hereinafter, the molding die of the present invention and the manufacturing method thereof, and the manufacturing method of the optical element and the optical apparatus will be described in detail. However, the present invention is not limited to the following embodiments, and the object of the present invention Within the range, it can be implemented with appropriate modifications. In addition, although description may be abbreviate | omitted suitably about the location where description overlaps, the meaning of invention is not limited.

<Embodiment>
One embodiment of the present invention is a molding die 10 including a lower die 20 and an upper die 30 that press the glass G. FIG. 1 is a cross-sectional view of a mold according to the first embodiment of the present invention.

[Lower mold and upper mold]
As shown in FIG. 1, the mold 10 includes a lower mold 20 and an upper mold 30. Among these, the upper surface of the lower mold 20 has a molding surface 211 on which the glass G is installed. The lower surface of the upper mold 30 faces the molding surface 211 of the lower mold 20, and has a molding surface 311 that presses the glass G while approaching and separating from the molding surface 211. Here, the lower mold 20 includes a mold base material 21 having a molding surface 211 and a protective film 23 provided on the surface of the molding surface 211. The upper mold 30 includes a mold base material 31 having a molding surface 311 and a protective film 33 provided on the surface of the molding surface 311.

(Protective film)
The protective films 23 and 33 provided in the mold 10 contain at least Ir and Re in such a content that the molar ratio of the Re content to the Ir content (Re / Ir) is 2.5 times or less. As a result, fogging of the molded glass G can be made difficult to occur. In addition, since the expensive Re content is reduced, the material costs of the protective films 23 and 33 can be reduced. Here, the molar ratio of the Re content to the Ir content is preferably 2.5 times or less, more preferably 2.3 times or less, and most preferably 2.2 times or less.

  On the other hand, the lower limit of the molar ratio of the Re content to the Ir content (Re / Ir) is preferably 0.5 times. Thereby, it can be made hard to produce the crack and damage | wound to the shape | molded glass G. FIG. At this time, the reason why it is difficult to cause cracks and scratches on the glass G is that when the glass G pressed by the lower mold 20 and the upper mold 30 is cooled, the coefficient of thermal expansion between the glass G and the protective films 23 and 33. Even if friction occurs between them due to the difference, it is assumed that the stress generated on the surface of the glass G due to the friction is reduced. Further, since the mechanical strength of the protective films 23 and 33 is increased, even if the mold 10 is repeatedly used for molding the glass G, the glass G to be molded can be brought into a desired surface state with high accuracy. it can. That is, the mold 10 can be preferably used particularly when mass-producing optical elements by a molding method (precision press molding) in which the glass G-shaped surface is used as the optical surface of the optical element. Here, the molar ratio of the Re content to the Ir content is more preferably 0.6 times or more, and most preferably 0.65 times or more.

  In addition, the protective films 23 and 33 contain at least one selected from the group consisting of Os, Pd, Pt, Au, Ru, Ta, and W, for example, in order to improve heat resistance and / or chemical durability. May be. The total content of these metals and Ir and Re is preferably 60% or more, more preferably 80% or more, and most preferably more than 99% in terms of molar fraction. Thereby, since the heat resistance and chemical durability of the protective films 23 and 33 are improved, the lifetime of the protective films 23 and 33 can be extended.

  Components other than those described above may be added as necessary as long as the characteristics of the protective films 23 and 33 are not impaired. However, it is preferable that the protective films 23 and 33 do not substantially contain Rh. Thereby, the crack and damage | wound to the shape | molded glass G can be made hard to produce more. This is presumably because the friction generated between the protective films 23 and 33 and the glass G is more easily reduced.

  The thickness of the protective films 23 and 33 is appropriately set according to the composition and mechanical strength of the protective film, but is preferably 50 nm or more on average, more preferably 100 nm or more, and 200 nm or more. Most preferably it is. Thereby, it is hard to produce the damage | wound and a crack to glass. This is presumably because the friction with the glass due to the area where the protective films 23 and 33 are insufficiently formed is reduced. At the same time, it is presumed that a film having a molar ratio of the Re content to the Ir content within a desired range is less likely to be peeled off, so that the fogging of the molded glass G can be made more difficult to occur. On the other hand, the thickness of the protective films 23 and 33 is preferably 3000 nm or less, more preferably 1500 nm or less, and most preferably 1000 nm or less. Thereby, since the amount of noble metal required for forming the protective films 23 and 33 is reduced, the material cost of the protective films 23 and 33 can be reduced.

(Mold base material)
The mold base materials 21 and 31 of the lower mold 20 and the upper mold 30 have molding surfaces 211 and 311 on which protective films 23 and 33 are formed. Here, although the materials of the mold base materials 21 and 31 are appropriately set according to the hardness of the glass G, the glass transition point (Tg), etc., the thermal expansion coefficient is the same as the thermal expansion coefficient of the protective films 23 and 33. It is preferable that the materials are substantially equal. Accordingly, when the mold base materials 21 and 31 on which the protective films 23 and 33 are formed are heated and cooled, the protective films 23 and 33 are hardly separated from the mold base materials 21 and 31. Therefore, the lifetime of the protective films 23 and 33 can be increased. The protective films 23 and 33 may be provided so as to cover the molding surfaces 211 and 311, and are not necessarily provided on the contact surfaces 213 and 313 on which the lower mold 20 and the upper mold 30 are in contact. .

  On the other hand, the mold base materials 21 and 31 are preferably made of a material having a thermal expansion coefficient equal to or lower than that of the glass G. Accordingly, when the glass G is cooled after being pressed, the mold base materials 21 and 31 are less likely to shrink than the glass G. Therefore, scratches and cracks on the glass G can be further reduced, and peeling of the protective films 23 and 33 and breakage of the mold base materials 21 and 31 can be reduced to extend the life of the mold 10. This is presumably because the stress acting from the glass G toward the mold base materials 21 and 31 is reduced.

  As such a member, for example, a carbide member such as tungsten carbide (WC) or silicon carbide (SiC) can be used. As a result, the mold base materials 21 and 31 are less likely to be scratched. Therefore, even when the molding surface of the glass G is used as the optical surface of the optical element (precision press molding), the glass G is highly accurate. The desired surface condition can be brought about. Moreover, since it can endure the large pressure at the time of pressing the glass G, the lifetime of the type | mold base materials 21 and 31 can be achieved.

  The shapes of the mold base materials 21 and 31 and the molding surfaces 211 and 311 are appropriately set according to the shape of the glass molded body produced by pressing.

(Interlayer film)
An intermediate film (not shown) may be provided between the protective films 23 and 33 and the mold base materials 21 and 31. This makes it difficult to expose the mold base materials 21 and 31 even when the protective films 23 and 33 are peeled off. Therefore, scratches on the molding surfaces 211 and 311 of the mold base materials 21 and 31 can be reduced, and the life of the mold base materials 21 and 31 can be extended. Further, since the protective films 23 and 33 and the mold base materials 21 and 31 are not in direct contact with each other, even if the protective films 23 and 33 and the mold base materials 21 and 31 are combined in such a manner that the adhesion strength is weakened, the protective film The peeling of 23 and 33 can be reduced. Here, the protective films 23 and 33 indicate the outermost film (that is, the film that is in direct contact with the glass G) outside the intermediate film.

  The intermediate film of the present invention may be a single film or a plurality of films. In particular, by forming the intermediate film with a plurality of films, scratches on the molding surfaces 211 and 311 can be further reduced, and a wider combination of the protective films 23 and 33 and the mold base materials 21 and 31 can be used.

[Body type]
The molding die 10 may have a barrel die (not shown) so as to abut against a part of the lower die 20 and the upper die 30 and surround these side surfaces. Thereby, since the orbit of the approach and separation of the lower mold 20 and the upper mold 30 is defined, the positional relationship between the molding surface 211 and the molding surface 311 can be kept constant. Accordingly, a glass G molded body having a desired shape can be stably produced.

  The material of the body mold is not particularly limited as long as it is a material that can withstand the heat when the glass G is pressed and is not easily deformed, but it is preferably formed of a material having low thermal conductivity. Thereby, the thermal efficiency in a shaping | molding process can be improved. As such a member, for example, a carbide member such as tungsten carbide (WC) or silicon carbide (SiC) can be used. Thereby, since it becomes difficult to make a damage | wound into a trunk mold, the molded object of the glass G which has a desired shape can be produced more stably.

[Method of manufacturing mold]
The manufacturing method of a shaping | molding die is the protection which contains Ir and Re on the molding surfaces 211 and 311 of the mold base materials 21 and 31 so that the molar ratio of the Re content to the Ir content is 2.5 times or less. A step of forming the films 23 and 33;

  The means for forming the protective films 23 and 33 is appropriately selected from means capable of forming a thin metal-containing film. Physical vapor deposition using plasma such as DC sputtering, magnetron sputtering, and ion plating. It is preferable to use these means. In such physical vapor deposition, fine particles of the material of the protective film are formed by plasma, so that metals having a high melting point and a high boiling point, such as Ir (boiling point 4428 ° C.) and Re (boiling point 5596 ° C.), have other low boiling points. Even when a metal is added, a metal film having a desired composition can be formed.

  At this time, the molar ratio of the Re content to the Ir content of the protective films 23 and 33 to be formed is 2.5 times or less, more preferably within a range of 0.5 times to 2.5 times. Thus, the supply amounts of Ir and Re from the raw materials are adjusted.

  Here, when the physical vapor deposition means is used, the means for adjusting the molar ratio of the Re content to the Ir content is to pulverize the raw materials such as Ir and Re to form a target having a composition close to the composition of the protective films 23 and 33. It may be formed and placed in a sputtering apparatus, and plasma may be generated by discharging toward this target. As a result, fine particles having a composition close to the composition of the protective films 23 and 33 are generated only by generating plasma once. Therefore, the number of times the plasma is generated and the thickness of the protective films 23 and 33 can be reduced. , 33 production costs can be reduced.

  Further, as a means for adjusting the molar ratio of the Re content to the Ir content, raw materials such as Ir and Re are arranged as targets in the respective sputtering apparatuses, and discharge is performed toward each of these targets to generate plasma. It may be generated. At this time, it is preferable to discharge toward each target while adjusting the pulse width and / or applied voltage of the power source used for discharge according to the content of each component of the protective films 23 and 33 to be formed. As a result, the amount of raw material fine particles corresponding to the pulse width of the power supply and the applied voltage is generated from the target, so that the content of each component contained in the protective films 23 and 33 can be finely adjusted in the sputtering apparatus. Become.

  Here, when forming the protective films 23 and 33, the protective films 23 and 33 cover the entire molding surfaces 211 and 311. Thereby, the damage | wound which arises in the glass G shape | molded can be reduced. This is presumably because the protective films 23 and 33 reduce friction with the glass G over the entire molding surfaces 211 and 311.

  The protective films 23 and 33 may be formed so as to cover the molding surfaces 211 and 311, and are not necessarily formed on the contact surfaces 213 and 313 on which the lower mold 20 and the upper mold 30 are in contact. However, by forming the protective films 23 and 33 so as to cover not only the molding surfaces 211 and 311 but also the contact surfaces 213 and 313, the mold base materials 21 and 31 when the lower mold 20 and the upper mold 30 are in contact with each other. Since the scratches on the mold are reduced, the dimensional accuracy of the glass G to be molded can be improved, and the lifetime of the mold base materials 21 and 31 can be extended.

[Production of optical elements]
Using this mold 10, the glass G is pressed to produce an optical element. The press molding apparatus used here is not particularly limited as long as it is an apparatus capable of heating and molding glass G. For example, glass G is supplied between lower mold 11 and upper mold 12 of mold 10. Use a press molding apparatus including a mechanism, a mechanism for heating and softening the glass G supplied to the mold 10, a mechanism for pressing the softened glass G, and a mechanism for cooling the pressed glass G. Is preferred. Thereby, after the glass G is softened, it is pressed and then cooled, so that the glass G can be molded smoothly, and for example, the productivity of the optical element can be increased.

  As the glass G to be supplied to the mold 10, at least lanthanum-based glass can be used. Lanthanum-based glass has a high refractive index (refractive index (nd) = 1.75 to 1.85) and relatively low dispersion (Abbe number (νd) = 35 to 45). The glass is preferably used for optical elements such as mirrors and prisms, but has the disadvantages that it is easily broken during press molding, easily scratched, and the glass after molding is likely to be fogged. In this respect, the use of the lanthanum-based glass mold 10 can reduce cracks, scratches, and fogging that occur in the glass G. At this time, the reason why it is difficult to cause cracks and scratches on the glass G in particular is that when the glass G pressed by the lower mold 20 and the upper mold 30 is cooled, the thermal expansion between the glass G and the protective films 23 and 33 is performed. Even if friction occurs between them due to the difference in rate, it is assumed that the stress generated on the surface of the glass G due to the friction is reduced.

Here, the lanthanum-based glass used as the glass G is selected from the group consisting of B ₂ O ₃ component, La ₂ O ₃ component and ZnO component, Nb ₂ O ₅ component, Ta ₂ O ₅ component and WO ₃ component. It is preferable to use one containing at least one kind. Thereby, the devitrification by the crystallization of the glass component at the time of press molding is reduced by improving the stability of the glass G. Therefore, the formation of scratches on the protective films 23 and 33 can be reduced, and the life of the protective films 23 and 33 can be extended. This is presumably because the formation of scratches due to the contact between the crystallized portion of the devitrified glass G and the protective films 23 and 33 is reduced.

More specifically, the composition of the lanthanum-based glass is preferably in the following range in terms of mass% based on the oxide.
(Preferred range)
SiO ₂ component 0-20%
B ₂ O ₃ component 10-30%
La ₂ O ₃ component 15-40%
ZrO ₂ component 0-15%
Nb ₂ O ₅ component 0-20%
Ta ₂ O ₅ component 0-20%
WO ₃ component 0-20%
ZnO component 10-30%
Li ₂ O component 0-5%

(More preferable range)
SiO ₂ component 1-15%
B ₂ O ₃ component 13-27%
La ₂ O ₃ component 20-40%
ZrO ₂ component 1-15%
Nb ₂ O ₅ component 1-17%
Ta ₂ O ₅ component 1-15%
WO ₃ component 1-15%
ZnO component 12-30%
Li ₂ O component 0.1-5%

(Most preferred range)
SiO ₂ component 1-7.5%
B ₂ O ₃ component 15.5-25%
However, SiO ₂ component + B ₂ O ₃ component 16.5 to less than 30% La ₂ O ₃ component 25 to 40%
ZrO ₂ component 1.5-10%
Nb ₂ O ₅ component 1-15%
Ta ₂ O ₅ component 1-10%
WO ₃ components 1-10%
ZnO component 15.5-30%
Li ₂ O component 0.6-5%

  Here, the “oxide equivalent composition” means that the oxide, composite salt, metal fluoride, etc. used as the raw material of the glass component of the present invention are all decomposed and changed into oxides when melted. It is the composition which described each component contained in glass by making the total mass of the said production | generation oxide into 100 mass%.

In addition to the above components, the lanthanum-based glass has other components (for example, GeO ₂ component, TiO ₂ component, Al ₂ O ₃ component, MgO component, CaO component, SrO component, BaO component, Sb ₂ O ₃ component). Etc.) can be added as necessary within the range not impairing the properties required of the glass. However, it is preferable that the PbO component is not substantially contained except for inevitable mixing, from the viewpoint of reducing environmental influences.

  As this lanthanum-based glass, a glass having a transition point (Tg) of 500 ° C. or higher is preferably used. Such a lanthanum-based glass inevitably has a high press molding temperature, and the glass G after molding is likely to be cracked, scratched or fogged. In this respect, by using the lanthanum glass having a transition point (Tg) of 500 ° C. or higher in the above-described mold 10, it is possible to make the glass G difficult to break at the time of molding, and to make the glass G after molding difficult to be scratched or clouded. At this time, the reason why cracks and scratches on the glass G can be made difficult is that the glass G and the protective film 23 even when the press molding temperature increases and the amount of expansion and contraction of the glass G during heating and cooling increases. This is presumably because the stress generated on the surface of the glass G is reduced by the friction with. Therefore, the transition point (Tg) of this lanthanum-based glass is preferably 500 ° C, more preferably 510 ° C, and most preferably 520 ° C.

  On the other hand, it is preferable to use a lanthanum glass having a transition point (Tg) of 590 ° C. or lower. Thereby, even when the glass G is heated at a lower temperature, the glass G softens to a viscosity that can withstand press molding. Therefore, the shrinkage | contraction amount of the shaping | molding die 10 and the glass G at the time of cooling after a press can be reduced, and the crack, damage | wound, and cloudiness to the glass G by shaping | molding can be reduced more. Further, the oxidation of the protective films 23 and 33 can be reduced, and the life of the protective films 23 and 33 can be extended. Therefore, the upper limit of the transition point (Tg) of the lanthanum-based glass is preferably 590 ° C, more preferably 580 ° C, and most preferably 570 ° C.

  Moreover, it is preferable to use a lanthanum-based glass having a yield point (At) of 530 ° C. or higher. Such a lanthanum-based glass inevitably has a high press molding temperature, and the glass G after molding is likely to be cracked, scratched or fogged. In this regard, by using the lanthanum glass having a yield point (At) of 530 ° C. or higher in the above-described mold 10, it is possible to make the glass G difficult to break at the time of molding, and to make the glass G after molding difficult to be scratched or clouded. Accordingly, the lower limit of the yield point (At) of this lanthanum-based glass is preferably 530 ° C., more preferably 540 ° C., and most preferably 550 ° C.

  On the other hand, it is preferable to use a lanthanum-based glass having a yield point (At) of 630 ° C. or lower. Thereby, the shaping | molding temperature of glass G can be made lower. Even when the glass G is heated at a lower temperature, the glass G can be press-formed into a desired shape with a smaller pressing force. Therefore, since the formation of scratches on the contact surfaces 213 and 313 of the mold 10 can be reduced, the life of the mold 10 can be extended. Therefore, the yield point (At) of this lanthanum-based glass is preferably 630 ° C, more preferably 620 ° C, and most preferably 610 ° C.

  Moreover, it is preferable to use the lanthanum glass that does not show devitrification in a devitrification test at 950 ° C. for 2 hours. Thereby, the devitrification due to crystallization of the glass component at the time of press molding is easily reduced. Therefore, the formation of scratches on the protective films 23 and 33 can be reduced, and the life of the protective films 23 and 33 can be extended. This is presumably because the formation of scratches due to the contact between the crystallized portion of the devitrified glass G and the protective films 23 and 33 is reduced.

  In addition, the glass G used by this invention can respond | correspond favorably to the press molding of the glass of the wider composition range and characteristic range containing the above-mentioned glass.

  The temperature to be heated when the lanthanum-based glass is press-molded is appropriately set according to the transition point (Tg), yield point (At), etc. of the lanthanum-based glass, and is preferably, for example, (At + 0) ° C. or higher. , (At + 5) ° C. or higher is more preferable, and (At + 10) ° C. or higher is most preferable. Thereby, the glass G is easily softened to a viscosity that can withstand press molding. Therefore, peeling of the protective films 23 and 33 from the mold base materials 21 and 31 can be reduced, and the life of the protective films 23 and 33 can be extended. This is presumably because the stress on the protective films 23 and 33 when the glass G is pressed is reduced. On the other hand, the temperature for press-molding the lanthanum-based glass is preferably, for example, 750 ° C. or less, more preferably 700 ° C. or less, and most preferably 650 ° C. or less. Thereby, since oxidation of the protective films 23 and 33 is reduced, the life of the protective films 23 and 33 can be extended.

[Production of optical equipment]
By this method, optical elements such as lenses and prisms are produced. It is also preferable to manufacture an optical device such as a camera or a projector using this optical element. Thereby, since cracks, scratches, and fogging due to press molding of the glass G are reduced, it is possible to increase the production efficiency of these elements while improving the reliability of the optical elements and optical devices.

  EXAMPLES Hereinafter, although this invention is demonstrated further in detail using an Example, this invention is not limited to a following example.

Example 1
As the mold base material of the mold, a lower mold base material and an upper mold base material each made of WC having a diameter of 15.0 mm and a height of 12.5 mm were used. Here, a molding surface was formed on the upper surface of the lower mold base material and the lower surface of the upper mold base material so as to face each other. The molding surface is formed by fitting a cylindrical body mold having an inner diameter of 15.0 mm into the lower mold base material, and an upper surface of the lower mold base material with the upper mold base material fitted into the body mold. When the upper die base material was brought into contact with the lower surface while facing each other, a substantially oblong spherical void having a diameter of 12 mm and a height of 2.5 mm was formed.

  Here, a 200 nm-thick protective film containing Ir: 50% and Re: 50% is formed on the entire upper surface of the lower mold base material and the lower surface of the upper mold base material, A lower mold and an upper mold were formed (Re / Ir = 1.0). Here, the protective film is formed by using a DC sputtering apparatus (model number: E-400S, manufactured by Canon Anelva Co., Ltd.) and discharging to a target made of Re at a voltage of 300 V while discharging to a target made of Ir at a voltage of 300 V. I went there.

  Using the lower mold and the upper mold thus formed, lanthanum-based glass was press-molded. Here, L-LAH81 (trade name) manufactured by OHARA INC. Was used as the lanthanum glass. Further, this glass had a transition point (Tg) of 566 ° C., a yield point (At) of 602 ° C., and no devitrification was observed in a devitrification test at 950 ° C. for 2 hours. .

  The above-mentioned glass is supplied onto the molding surface of the lower mold of the mold, and a cylindrical body mold made of WC having an inner diameter of 15.0 mm, an outer diameter of 20.0 mm, and a height of 22.0 mm is fitted into the lower mold, The mold was fitted into this body mold, and the lower mold, the upper mold, and the body mold were assembled into a molding mold. Next, after the mold was heated to 620 ° C. and softened, the upper mold was lowered with a force of 100 kgf to press the glass, and the glass was press-molded. After press molding, the mold was gradually cooled to about 100 ° C., and then the mold was disassembled into an upper mold and a lower mold, and the optical element was taken out.

  As a result, when 100 glasses were molded using the above-described method, one glass was broken and no glass was scratched. On the other hand, fogging did not occur in the molded glass.

(Example 2)
A protective film having a thickness of 500 nm containing Ir: 60% and Re: 40% is formed on the entire upper surface of the lower mold base material and the lower surface of the upper mold base material. An upper mold was formed (Re / Ir = 0.67). Other steps were performed in the same manner as in Example 1.

  As a result, when 100 glasses were molded using the above-described method, there were 2 broken glasses and 1 damaged glass. On the other hand, fogging did not occur in the molded glass.

(Example 3)
A 300 nm-thick protective film containing Ir: 50%, Re: 40%, Rh: 10% is formed on the entire upper surface of the lower mold base and the lower surface of the upper mold base. Thus, a lower mold and an upper mold were formed (Re / Ir = 0.8). Other steps were performed in the same manner as in Example 1.

  As a result, when 100 glass pieces were molded using the above-described method, 20 pieces of broken glass were produced and 10 pieces were damaged. On the other hand, fogging did not occur in the molded glass.

(Comparative Example 1)
A protective film having a thickness of 300 nm containing Ir: 80% and Re: 20% is formed on the entire upper surface of the lower mold base material and the lower surface of the upper mold base material. An upper mold was formed (Re / Ir = 0.25). Other steps were performed in the same manner as in Example 1.

  As a result, when 100 glasses were molded using the above-described method, 50 glasses were broken and 20 were scratched. On the other hand, fogging did not occur in the molded glass.

(Comparative Example 2)
A protective film having a thickness of 300 nm containing Ir: 20% and Re: 80% is formed on the entire upper surface of the lower mold base material and the lower surface of the upper mold base material. An upper mold was formed (Re / Ir = 4.0). Other steps were performed in the same manner as in Example 1.

  As a result, when 100 glasses were molded using the method described above, 60 of the molded glasses were fogged. On the other hand, the molded glass was not cracked or scratched.

  When the results of Examples 1 to 3 and Comparative Examples 1 and 2 are compared, the protective film containing Ir and Re in such a content that the molar ratio of the Re content to the Ir content is 0.5 to 2.5 times It can be seen that when the mold formed with is used for molding lanthanum-based glass, the molded glass can be hardly cracked or scratched, and can be hardly fogged.

(Reference Example 1)
Using lower and upper molds formed in the same manner as in Example 1, fluoride glass was press-molded. Here, S-FPL51 (trade name) manufactured by OHARA INC. Was used as the fluoride glass. Further, this glass had a transition point (Tg) of 458 ° C., a yield point (At) of 489 ° C., and no devitrification was observed in a devitrification test at 950 ° C. for 2 hours. . Other steps were performed in the same manner as in Example 1.

  As a result, when 100 glasses were molded using the above-described method, 40 glasses were broken. On the other hand, fogging did not occur in the molded glass.

(Reference Example 2)
Using the lower mold and the upper mold formed in the same manner as in Comparative Example 1, fluoride glass was press-molded. Here, S-FPL51 (trade name) manufactured by OHARA INC. Was used as the fluoride glass. This glass had no devitrification in the devitrification test at 950 ° C. for 2 hours. Other steps were performed in the same manner as in Comparative Example 1.

  As a result, when 100 glasses were molded using the above-described method, 40 glasses were broken and 10 were damaged. On the other hand, fogging did not occur in the molded glass.

  When the results of Example 1 and Reference Example 1 are compared, even when press molding is performed using lanthanum-based glass, it is not much different from the case where press molding is performed using fluoride glass other than lanthanum-based glass. It can be seen that good molding results can be obtained. On the other hand, when the results of Comparative Example 1 and Reference Example 2 are compared, when press forming is performed using lanthanum-based glass, cracks and cracks are smaller than when pressing is performed using fluoride glass other than lanthanum-based glass. It can be seen that the number of scratches has increased significantly.

  From the above, it can be seen that the molding die of the present invention can make it difficult to cause cracks and scratches in the molded glass, especially when used for molding lanthanum-based glass, and can hardly cause fogging.

DESCRIPTION OF SYMBOLS 10 Mold 11 Lower mold 12 Upper mold 20 Lower mold 21 Mold base material 23 Protective film 30 Upper mold 31 Mold base material 33 Protective film 211 Molding surface 213 Contact surface 311 Molding surface 313 Contact surface

Claims (10)

A mold comprising a mold base material having a molding surface, and a protective film provided on the molding surface,
The protective film is
Ir and Re are contained in such a content that the molar ratio of the Re content to the Ir content is 0.6 times or more and 2.5 times or less,
The total content of Os, Pd, Pt, Au, Ru, Ta, W, Ir, and Re, containing more than 99% by mole fraction,
The thickness is 50 nm or more and 3000 nm or less,
The said shaping | molding die is a shaping | molding die used for shaping | molding lanthanum-type glass (however, except that the protective film contains Au). The protective layer, according to claim 1 Symbol mounting molds containing no Rh substantially. On the molding surface of the mold base material,
Ir and Re are contained in such a content that the molar ratio of the Re content to the Ir content is 0.6 times or more and 2.5 times or less, and Os, Pd, Pt, Au, Ru, Ta, W, Ir, and Re And a step of forming a protective film having a thickness of 50 nm or more and 3000 nm or less, except that the total content is more than 99% by mole fraction (except that the protective film contains Au). A manufacturing method of a mold used for forming a lanthanum glass. The manufacturing method of the shaping | molding die of Claim 3 which does not contain Rh substantially in the said protective film. Method of manufacturing an optical element having a step of press-molding the lanthanum-based glass with claim 1 or 2 mold according. As the lanthanum-based glass, a B ₂ O ₃ component, a La ₂ O ₃ component and a ZnO component, and at least one selected from the group consisting of an Nb ₂ O ₅ component, a Ta ₂ O ₅ component and a WO ₃ component are contained. The manufacturing method of the optical element of Claim 5 using what to do. As the lanthanum-based glass, the refractive index (nd) has an optical constant in the range of 1.75 to 1.85 and the Abbe number (νd) in the range of 35 to 45, and the mass percentage based on the oxide.
SiO ₂ component 0-20%
B ₂ O ₃ component 10-30%
La ₂ O ₃ component 15-40%
ZrO ₂ component 0-15%
Nb ₂ O ₅ component 0-20%
Ta ₂ O ₅ component 0-20%
WO ₃ component 0-20%
ZnO component 10-30%
Li ₂ O component 0-5%
The transition point (Tg) is 500 to 590 ° C., the yield point (At) is 530 to 630 ° C., and no devitrification is observed in the devitrification test at 950 ° C. for 2 hours. The manufacturing method of the optical element of Claim 6 using a thing. A method for producing an optical device using an optical element obtained by press-molding a lanthanum-based glass using the mold according to claim 1 or 2 . As the lanthanum-based glass, a B ₂ O ₃ component, a La ₂ O ₃ component and a ZnO component, and at least one selected from the group consisting of an Nb ₂ O ₅ component, a Ta ₂ O ₅ component and a WO ₃ component are contained. The manufacturing method of the optical instrument of Claim 8 using what to do. As the lanthanum-based glass, the refractive index (nd) has an optical constant in the range of 1.75 to 1.85 and the Abbe number (νd) in the range of 35 to 45, and the mass percentage based on the oxide.
SiO ₂ component 0-20%
B ₂ O ₃ component 10-30%
La ₂ O ₃ component 15-40%
ZrO ₂ component 0-15%
Nb ₂ O ₅ component 0-20%
Ta ₂ O ₅ component 0-20%
WO ₃ component 0-20%
ZnO component 10-30%
Li ₂ O component 0-5%
The transition point (Tg) is 500 to 590 ° C., the yield point (At) is 530 to 630 ° C., and no devitrification is observed in the devitrification test at 950 ° C. for 2 hours. The method for manufacturing an optical apparatus according to claim 9, wherein a thing is used.

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