JP3153871B2 - Method for manufacturing glass optical element - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a high precision glass optical element.

[0002]

2. Description of the Related Art Various studies have been made on techniques for manufacturing a glass optical element with high precision by press-molding a glass material in a mold. For example, as a mold for press-molding a glass material, a mold having a molding surface made of silicon carbide, silicon nitride, or the like is well known. Japanese Patent Publication No. 4-61816 discloses a mold in which a hard carbon film is formed on a surface of silicon carbide by a sputtering method. Further, Japanese Patent Application Laid-Open No. 2-199036 discloses a mold in which an i-carbon film is coated by an ion plating method on a substrate made of silicon carbide whose surface is formed by a CVD method.

As described above, many studies have been made on molding dies in a glass optical element manufacturing technique by press molding. However, the fact is that the glass material to be press-formed has not been sufficiently studied so far. In general, it is said that glass having a low softening temperature is advantageous as a glass material for producing a high-precision glass optical element by press molding. There is no prior art document that clearly discloses which glass is advantageous when considering the life of a mold in relation to silicon (e.g., silicon).

Among the conventionally well-known optical glasses, a glass having a relatively low softening temperature is a flint-based optical glass. However, since this glass contains PbO, PbO is reduced during press molding. Therefore, there is a problem that Pb particles are precipitated. Further, although the flint optical glass is a high dispersion glass, the refractive index n _d 1.55 recently
There is an extremely high demand for using heavy uranium glass having an Abbe number ν _{d of} 1.63 or more as a material for a biconvex aspheric lens.

[0005]

Silicon carbide, silicon nitride, etc. are extremely excellent materials such as high-temperature hardness and high-temperature strength. For example, if the surface of a molding die is produced by a CVD method, it is dense without defects such as pores. Yes, it can be mirror-finished. However, a mold made of these materials is oxidized on its extreme surface and has a layer of silicon oxide of about several tens of angstroms, and therefore contains a large amount of glass modifying components composed of alkali or alkaline earth cations. When press-molding glass made of borosilicate glass, silicate glass, etc., the glass fuses and at the same time stress concentration occurs at some points in the mold during cooling, so the surface of the mold is cut out in a spot shape. (Hereinafter, this phenomenon is referred to as pullout). As disclosed in Japanese Patent Publication No. 4-61816 and JP-A-2-199036, coating the surface of a mold silicon carbide or silicon nitride with a carbon-based film is extremely effective for preventing fusion and pull-out. Means. However, what is always a problem in the film forming technique is that it is difficult in terms of production technology to completely form a film over the entire press-formed surface of the mold.
When viewed microscopically, there are foreign matters attached at several places, and there is a missing film. This is described in Japanese Unexamined Patent Application Publication No.
No. 45, which is well known in the art.

[0006] Further, even if the press-forming atmosphere is set to a non-oxidizing atmosphere, the carbon-based film as described in Japanese Patent Publication No. 4-61816 or JP-A-2-199036 can be used.
Since it is oxidized by moisture and oxygen inside and outside the glass, it is necessary to peel off and remove the carbon-based film after a certain period, instead of a permanent film, to perform a regeneration operation to form a new carbon-based film.
Therefore, at a certain probability, problems such as adhesion of foreign substances and film loss occur during film formation. Then, if the press forming is repeated at the foreign matter attaching portion or the film missing portion, pull-out occurs at a certain probability. If pull-out occurs significantly, the resulting glass optical element will have defects and expensive molds can no longer be used.

[0007]

Means for Solving the Problems As a result of diligent studies, the present inventors have found that a defect is found in a defect portion of a fusion-preventing thin film formed on a molding surface of a molding die mainly containing silicon carbide and / or silicon nitride. The pull-out due to the oxidation of the silicon carbide and / or silicon nitride and the fusion of the glass to be molded is caused by a transition point of 530 as the glass to be molded.
° C or lower, with a yield point of 565 ° C or lower.
It has been found that the use of glass that does not contain bO significantly suppresses the use of the glass and significantly extends the life of the mold.

The present invention has been completed based on the above findings. At least the molding surface is made of a material containing silicon carbide and / or silicon nitride as a main component, and a thin film for preventing fusion is further formed on the molding surface. A glass material having a transition point of 530 ° C. or less, a sag point of 565 ° C. or less, and containing no PbO as a glass component is put into the mold, and subjected to pressure molding in a heated and softened state. A gist of the invention is a method for manufacturing a glass optical element.

Hereinafter, the present invention will be described in detail.

In the method for producing an optical glass element of the present invention, at least a molding surface is made of a material containing silicon carbide and / or silicon nitride as a main component,
A molding die in which a thin film for preventing fusion is further molded on the molding surface is used.

In the above mold, silicon carbide and / or
Alternatively, the molding surface composed of a material containing silicon nitride as a main component may be molded by the substrate material itself of a molding die composed of silicon carbide and / or silicon nitride, or directly or on a substrate material such as a cemented carbide. CVD of a thin film of silicon carbide and / or silicon nitride via an intermediate layer
It may be formed by forming a film by a method, a sputtering method, a plasma CVD method, or the like. A silicon carbide / silicon nitride thin film formed by a CVD method is preferable because of its excellent denseness.
A β-SiC thin film formed by a CVD method is particularly preferable. In addition,
The molding surface may be made of a material containing silicon carbide and / or silicon nitride as a main component. Therefore, it is needless to say that only silicon carbide and / or silicon nitride can be used. Alternatively, ceramics containing 90% by weight or more of silicon nitride, for example, S
Silicon nitride ceramics such as iAlON can also be used.

When a thin film containing silicon carbide and / or silicon nitride as a main component is formed on a base material such as a cemented carbide, the thickness is preferably 0.02 to 2 μm. Also, a thick film may be formed on the silicon carbide and / or silicon nitride sintered body by a CVD method,
Those manufactured by the method D may be used.

In the molding die, the thin film for preventing fusion provided on the molding surface includes carbon (hard carbon, i-carbon, etc.), platinum alloy (Pt-Rh alloy, Pt-Rh-Au alloy, Pt-Rh- Au-Ir alloy), titanium, titanium carbide, titanium nitride, chromium, chromium carbide, chromium nitride, boron nitride, silicon carbide, silicon nitride, and the like are preferable. As the carbon thin film, a carbon thin film composed of an amorphous and / or crystalline single component layer or a mixed layer having a graphite structure and / or a diamond structure is preferable because it is particularly excellent in anti-fusing properties. This carbon thin film is C
Some have -H bonds and some do not have C-H bonds, and any of them may be used. These thin films for preventing fusion are formed by using a film forming method suitable for each material.

The thickness of the thin film for preventing fusion is 0.02 to 2 μm.
m is preferred. If it is less than 0.02 μm, it is insufficient to prevent fusion, and if it exceeds 2 μm, the surface roughness is deteriorated and the shape retention of the mold is also deteriorated.

It is to be noted that an intermediate layer may be provided prior to forming the fusion preventing thin film on the molding surface. As the intermediate layer, a material similar to that of the above-mentioned fusion preventing thin film is appropriately selected and used.

The molding glass used in the method for manufacturing a glass optical element of the present invention has a transition point of 530 ° C. or less, a sag point of 565 ° C. or less, and PbO as a glass component.
Use a glass material that does not contain The reason for limiting the transition point and the yield point as described above is that when the transition point exceeds 530 ° C. and the yield point exceeds 565 ° C., many cracks (cracks) and pull-outs occur on the surface of the mold, whereas If the transition point is 530 ° C. or lower and the yield point is 565 ° C. or lower, the occurrence of cracks (cracks) and pull-out on the surface of the mold is significantly suppressed, and the life of the mold is extended. The reason why PbO is not required as a glass component is that if PbO is included, PbO is reduced during press molding and Pb particles are precipitated.

The transition point is 530 ° C. or less, and the sag point is 565 ° C.
Or less, preferable glass that does not contain PbO, the composition is in weight%, SiO ₂ 28~55%,
Containing 5 to 30 % of B ₂ O ₃ , SiO ₂ + B ₂ O ₃ 46
_{~70%, SiO 2 / B 2} O 3 1.3~12.0 ( wt
Borosilicate glass, and the borosilicate glass
Is Li ₂ O 5-12%, Na ₂ O 0-5%,
_{K 2 O 0~5%, Li 2} O + Na 2 O + K 2 O 5~12
%, BaO 0-40%, MgO 0-10%, CaO
0-23%, SrO 0-20%, ZnO 0-20
%, BaO + MgO + CaO + SrO + ZnO 10
44%, SiO ₂ + B ₂ O ₃ + Li ₂ O + BaO + CaO
It is preferable to contain 72% or more. BaO is 10
It is particularly preferred that it is ４０40%. The above borosilicate glass
Further _{Al 2 O 3 1~7.5%, P} 2 O 5 0~3
_{%, La 2 O 3 0~15%} , Y 2 O 3 0~5%, Gd 2
_{O 3 0~5%, TiO 2 0~3} %, Nb 2 O 5 0~3
%, ZrO ₂ 0-5%, La ₂ O ₃ + Y ₂ O ₃ + Gd ₂ O _{3
1~15%, As 2 O 3 0~0.5} %, Sb 2 O 3 0
０．５0.5%, As ₂ O ₃ + Sb ₂ O ₃ 0.005 to 0.5
%.

The above composition is satisfied, and the refractive index n _d 1.5
Specific examples of glasses satisfying the Abbe number ν _d of 5 to 1.63 and satisfying the stability and chemical durability as glass include those shown in Tables 1, 2, 3 and 4.

In the above glass composition, SiO 2 is preferably used.
₂ is 30 to 55%, B ₂ O ₃ is 5 to 30%, SiO ₂ + B ₂
O ₃ is 56~70%, Li ₂ O is 7~12%, Na ₂ O is 0~3%, K ₂ O is _{0~3%, Li 2 O + Na} 2 O + K 2 O
Is 7 to 12%, BaO is 0 to 30%, and MgO is 0 to 5
%, CaO is 0 to 23%, SrO is 0 to 20%, ZnO
0-10% _{is, SiO 2 + B 2 O 3} + Li 2 O + BaO + C
aO 72% or more, Al ₂ O ₃ is 1 to 7.5% P ₂ O ₅ is 0 to 2% La ₂ O ₃ is 0% Y ₂ O ₃ is 0-3%,
Gd ₂ O ₃ is 0 to 3%, TiO ₂ is 0~2%, Nb ₂ O ₅ is 0 to 2%, ZrO ₂ is _{0~3%, La 2 O 3 +} Y 2 O 3 + G
d ₂ O ₃ is 1~10%, As ₂ O ₃ is 0 to 0.04%, Sb
₂ O ₃ is 0 to 0.5%, and As ₂ O ₃ + Sb ₂ O ₃ is 0.005%.
~ 0.5%.

[0020]

[Table 1]

[0021]

[Table 2]

[0022]

[Table 3]

[0023]

[Table 4]

In general, when the transition point and the yield point of the glass are lowered, the chemical durability is deteriorated. One of the features of the glass to be formed used in the present invention is that the glass contains 5 to 12% by weight of Li ₂ O. , Lowering the transition point and the yield point without deteriorating the chemical durability.

In the glass material used as the glass to be molded in the present invention, the glass material is used as a defoaming agent when melting the glass, and / or
Or As ₂ O ₃ , Sb ₂ O ₃ used as a coloring inhibitor
Is easily volatilized, releases oxygen, and may cause oxidation of silicon carbide and silicon nitride on the molding surface. Therefore, the content is preferably 0.005 to 0.5% by weight as described above. In particular, the content is preferably 0.005 to 0.04% by weight.

In the glass material, there are water adsorbed and hydroxyl groups on the surface, hydroxyl groups fixed in the glass structure and water molecules taken in. Of these, the adsorbed water on the surface is scattered by pre-drying or low-temperature heating in the press device, so that it hardly participates in the oxidation of the mold. Regarding the hydroxyl groups on the surface, if a cold-polished glass material is used, a hydrated layer is formed by polishing. Therefore, it is advantageous to use a hot-formed glass material without a hydrated layer. The total amount of hydroxyl groups and water molecules contained in the glass material is preferably 50 ppm or less from the viewpoint of preventing oxidation of the mold, and 25 ppm or less.
It is particularly preferred that the content be not more than ppm.

The glass material to be molded is obtained by melting glass materials such as oxides, carbonates and nitrates, but nitrates decompose to release oxygen, which may cause oxidation of the mold. There is. Therefore, the nitrate content in the glass raw material is preferably set to 10% by weight or less in terms of oxide, but nitrate is a P crucible material for melting glass.
Since it plays a role in preventing precipitation of reduced particles of t, it is necessary to be 1% by weight or more in terms of oxide. Therefore, the nitrate content is preferably 1 to 10% by weight, particularly preferably 2 to 5% by weight.

As a glass material to be molded, molten glass is allowed to flow down from an outflow pipe of a glass melting furnace,
It is preferable to use a massive preform having a predetermined weight. Examples of the shape of the massive preform include a spherical shape and a marble shape. In particular, wrinkles,
It is preferable to use a preform which has almost no defects such as protrusions, dents, dirt, and deposits and has a free surface on the whole surface. Such a preform does not have a surface hydration layer peculiar to cold polishing, there is no adverse effect due to deposits and the like,
This is preferable because a glass material can be produced at low cost.

In the method for producing a glass optical element according to the present invention, the above glass material is placed in a molding die as a glass to be molded, and pressure-molded in a heated and softened state to obtain a glass optical element.

The pressure molding is performed in a non-oxidizing atmosphere (for example, N ₂ , oxygen content 15 ppm or less and water content 50 ppm or less).
2% H ₂ + 98% N ₂ ). The reason why the oxygen content is preferably 15 ppm or less and the non-oxidizing atmosphere is preferable is that when the oxygen content is as small as 15 ppm or less, cracks and pull-outs caused by glass fusion accompanying oxidation of silicon carbide or silicon nitride on the molding surface are reduced. This is because generation can be suppressed. A particularly preferred oxygen content is 10 p
pm or less.

The water content in the atmosphere is 50 ppm
The following is preferable because, if it exceeds 50 ppm, the oxidation of silicon carbide or silicon nitride on the molding surface is promoted and cracks and pull-outs are likely to occur.
This is because, when it is not more than m, oxidation and accompanying pull-out are suppressed. The water content in the atmosphere is particularly preferably at most 25 ppm.

According to the glass optical element manufacturing method of the present invention described above, a glass having a transition point of 530 ° C. or less and a sag point of 565 ° C. or less and containing no PbO is used as a glass to be molded. The probability of the occurrence of pull-out can be significantly reduced, and the life of the mold can be greatly extended. For example, the pull-out occurrence probability can be reduced to 1/3 or less, and the life of the mold can be increased to 3 times or more as compared with the case of using conventional glass in which at least one of the transition point and the yield point exceeds the above value.

[0033]

【Example】

Example I Cracks and pull-outs occur even when using a mold having a fusion preventing thin film formed on a molding surface made of silicon carbide or silicon nitride as described above, because of the inevitable defects of the fusion preventing thin film. This is because the exposed surface of the silicon carbide or silicon nitride reacts with the glass and is removed along with the glass.

In order to further clarify the operation and effect of the present invention, various glass materials are pressed using a mold (mirror-polished flat plate) having a silicon carbide molding surface on which no thin film for preventing fusion is formed. Molded. The relationship between the transition point and the yield point of the glass to be formed and the occurrence of cracks and pull-outs was examined.

The glass to be molded used has a transition point of 4
The yield point is varied in the range of 90 to 550 ° C and in the range of 520 to 590 ° C. The refractive index n _d is 1.5
From 5 to 1.63, although the Abbe number [nu _d is of 55 or more, and particularly n _d 1.59, mainly those of [nu _d 61.

The molding conditions are as follows.

Shape of glass to be molded: Preformed body hot-formed into a marble shape (volume 250 mm ³ ) Mold (flat plate): A viewpoint for searching for a glass which is less likely to crack or pull out even if the surface of the mold is slightly oxidized. Was used after oxidizing the surface of silicon carbide with oxygen plasma (the thickness of the oxide layer was 30 to 40 angstroms). Five molding dies were used for each glass to be molded.

Atmosphere: 2% H ₂ + 98% N ₂ Molding temperature: Temperature corresponding to a glass viscosity of 10 ^6.9 poise (slightly lower than ordinary pressing conditions) Molding pressure: 120 kg / cm ² Molding time: 60 seconds Cooling rate: 110 ° C./min Number of moldings: 5 times (5 moldings were performed on each of 5 molding dies) Composition of glass used, refractive index n _d , Abbe number ν _d , transition point Tg, yielding point Ts, water resistance Dw, acid resistance Da, the sum of cracks and pull-out number generated by the press temperature (temperature glass viscosity corresponding to 10 ^6.9 poise) and five pressing (average of five mold) Table 5 and Table 6
Shown in FIG. 1 shows the relationship between the yield point and the number of pullouts and cracks. From Tables 5 and 6, and FIG. 1, there is a strong correlation between the yield point of the glass and the number of cracks and pull-outs. Is apparently reduced, especially at the transition point 53
It has become clear that it is preferable to use glass having a temperature of 0 ° C. or less and a sag point of 565 ° C. or less.

In the actual press forming in the present invention, since a forming die having a thin film for preventing fusion is used on the forming surface, cracks and pull-outs occur when glass having a transition point of 530 ° C. or lower and a sag point of 565 ° C. or lower is used. It has been clarified that the probability of occurrence is significantly reduced as compared with the case where the anti-fusing film is not provided.

It should be noted that Table 6 shows that the comparative glass Nos.
11, As ₂ O ₃ 0.1 wt%, wherein the Sb ₂ O ₃ 0.2 wt%, the glass of Comparative No. 12 is As ₂ O ₃ 0,
01 wt%, wherein the Sb ₂ O ₃ 0.01 wt%, the former is As ₂ O ₃ than the latter, Sb ₂ O is significantly more ₃ content.
In addition, glass no. No. 11 uses a nitrate raw material. No. 12 does not use a nitrate raw material. Nevertheless, from Table 6 and FIG. 1, the numbers of cracks and puouts of both are slightly different.

The glass N contained in the glass of the present invention
o. 9 and glass no. No. 10 uses nitrate raw material and As
_{Although it} contains a large amount of ₂ O ₃ and Sb ₂ O ₃ , the number of cracks and pull-outs is small.

Therefore, nitrate as a raw material, As in glass
It is clear that the effects of ₂ O ₃ and Sb ₂ O ₃ on cracks and pullouts are much smaller than the effects of the glass transition point and yield point on cracks and pullouts. This is supported by Example III described below.

Among the alkaline earth oxides, the use of CaO rather than BaO tends to reduce the number of cracks and pull-outs.

[0044]

[Table 5]

[0045]

[Table 6]

Example II In order to investigate the effect of moisture in the glass to be molded, the sample No.
Regarding the glass of No. 8, at the time of melting the glass, dehydrated glass was produced by flowing carbon tetrachloride as a gas through a pipe through the glass melt and bubbling. The water content of the dehydrated glass was 7 ppm. On the other hand, the water content of the glass not subjected to the dehydration treatment was 95 ppm. The mold was treated with an acid so that the surface had almost no oxidized layer, and as the molding atmosphere, an atmosphere in which water was removed to reduce the water content to 50 ppm or less was used. As a result of pressing 15 times at a press forming temperature of 630 ° C. and a pressing pressure of 180 kg / cm ² , the total (average) of the number of cracks and pull-outs was 4.0 in non-dehydrated glass (water content: 95 ppm). (7 ppm of water) decreased to 2.5 pieces. As a result of various studies using other halogen-containing gas, oxygen gas, carbon dioxide gas, nitriding gas, argon gas, etc., the total amount of hydroxyl groups and water molecules contained in the glass was
It has been found that reducing the content to 50 ppm or less in terms of water molecules is effective in reducing cracks and pull-out.

Example III The effects of using nitrate as a glass material and the effects of As ₂ O ₃ and Sb ₂ O _{3 in} the glass to be molded were examined. The basic composition of the glass used was No. 5 in Table 5. The following three types of glasses are the same as the one glass.

Glass (a): BaO as a raw material for BaO
(No ₃ ) ₂ and carbonate as a raw material for other alkali and alkaline earth oxides. It contains 0.2% by weight of As ₂ O ₃ and 0.2% by weight of Sb ₂ O ₃ .

Glass (b): BaO as a raw material for BaO
(No ₃ ) ₂ and carbonate as a raw material for other alkali and alkaline earth oxides. As ₂ O ₃ and Sb
Does not contain ₂ O ₃ .

Glass (c): BaC as a raw material of BaO
O ₃ was used, and carbonate was also used as a raw material for other alkali and alkaline earth oxides. As ₂ O ₃ and Sb ₂ O ₃
Not contained.

A glass molded body (250 mm ³ ) made of the above glasses (a), (b) and (c) is prepared, and each glass molded body is ion-plated on a silicon carbide molding die and silicon carbide. In a 2% H ₂ + 98% N ₂ atmosphere by placing them on a mold having an i-carbon film formed at 300 ° C. by a sputtering method and a mold having a hard carbon film formed thereon at 300 ° C. by a sputtering method on silicon carbide. 700 ° C, 1
It was heat-treated while holding for a time. A temperature of 700 ° C. is equivalent to a glass viscosity of 10 ^4.6 poise, but the actual pressing is performed at a glass viscosity of 10 ^7.6 poise or more.
(10 ^4.6 poise) is a condition under which the glass is more easily fused to the forming die than at the time of actual pressing.

Table 7 shows the results of observing the state of fusion between the glass molded body and the mold after the heat treatment and the state of foaming at the interface between the glass molded body and the mold, and measuring the contact angle.

[0053]

[Table 7]

According to Table 7, when the surface of the mold is made of silicon carbide, fusion is observed in all of glasses (a), (b) and (c), and in particular, the glass is obtained using nitrate as a raw material of BaO. It was also found that the glass (a) containing As ₂ O ₃ and Sb ₂ O ₃ in the glass had a remarkable degree of fusion. Therefore, the glass is made of As ₂ O ₃ , Sb _{2 to} prevent fusion with silicon carbide.
It is clear that it is better not to contain O ₃ as much as possible. In a mold in which an i-carbon film and a hard carbon film were formed on silicon carbide, fusion of glass was not recognized because these films were anti-fusion films. On the other hand, the foaming of the interface is significantly foaming in the case of glass (a) in any of the three molds, glass for foaming prevention of interface does not include as much as possible the _{As 2 O 3, Sb 2 O} 3 It turned out to be better.

Regarding the wettability, it is clear that the contact angle of glass (c) without using nitrate as the raw material is the largest and is preferable.

From the above, although a clear difference was not found in Example I, it is effective to reduce As ₂ O ₃ and Sb ₂ O _{3 and} to reduce nitrate in the raw material.

Example IV The effect of moisture in a press molding atmosphere was examined. The glass used was No. in Table 6. A glass preform (250 mm ³ ) which was hot-formed into a marble shape was used.
The atmosphere gas consists of 2% H ₂ + 98% N ₂ ,
(I) A gas from which water was removed by providing a zeolite dry column at the inlet to the press device, and (ii) a gas introduced with ordinary piping were used. The amount of residual moisture in the atmosphere is
In the case of (i), it was 18 ppm, and in the case of (ii), it was 71 ppm.
The mold was subjected to an acid treatment to dissolve and remove an oxide layer on the surface, and the mold was started to be used with almost no oxide layer. Press molding temperature 630 ° C. (temperature at which the glass viscosity corresponding to 10 ^6.9 poise), under the conditions of a press molding pressure 120 kg / cm ^2, each 10 times pressed results in each of eight molds, cracks and in (ii) The total (average) of the number of pullouts was 2.5, but in (i), the number was reduced to 1.3. As a result of various studies, it was found that setting the water content in the atmosphere to 50 ppm or less was effective in reducing cracks and pull-out.

[0058]

According to the method for manufacturing a glass optical element of the present invention described above, cracks and pull-outs caused by glass fusion accompanying oxidation of silicon carbide and silicon nitride constituting the molding surface of the mold are eliminated. Since it can be suppressed remarkably, the mold used has a long life, and the obtained glass optical element has extremely few defects.

[Brief description of the drawings]

FIG. 1 is a graph showing the relationship between the yield point of glass and the number of cracks and pull-outs.

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-3-88731 (JP, A) JP-A-5-201743 (JP, A) JP-A-5-246735 (JP, A) JP-A-61- 136928 (JP, A) JP-A-6-144868 (JP, A) JP-A-2-14839 (JP, A) JP-B-4-61816 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) C03B 11/00

Claims (15)

(57) [Claims] 1. The method according to claim 1, wherein at least the molding surface has silicon carbide and / or
Alternatively, a molding die made of a material containing silicon nitride as a main component and further having a fusion-preventing thin film formed on the molding surface is used, and the transition point is 530 ° C. or lower and the yield point is 565 in the molding die. C. or lower, and As ₂ O ₃ + Sb as a glass component
_While containing 0.005 to 0.04% by weight of ₂ O ₃ ,
A method for producing a glass optical element, wherein a glass material containing no PbO is put in, and pressure-molded in a state of being heated and softened. 2. Composition of a glass material as a glass to be molded
The total content of hydroxyl groups and water molecules contained in
The glass according to claim 1, which is 50 ppm or less in terms of conversion.
Manufacturing method of optical element. 3. The glass material to be molded is nitric acid.
Glass source having a salt content of 1 to 10% by weight on an oxide basis
3. The method according to claim 1, which is obtained by melting a material.
A manufacturing method of the glass optical element according to the above. 4. The method according to claim 1, wherein the pressure molding is performed with an oxygen content of 15 ppm or less.
Perform in a non-oxidizing atmosphere with a water content of 50 ppm or less.
The production of the glass optical element according to any one of claims 1 to 3.
Construction method. 5. The method according to claim 1, wherein at least the molding surface has silicon carbide and / or
Alternatively, a molding die made of a material containing silicon nitride as a main component and further having a fusion-preventing thin film formed on the molding surface is used, and the transition point is 530 ° C. or lower and the yield point is 565 in the molding die. C. or lower, containing no PbO as a glass component and having a hydroxyl group and water molecule content of 5
A method for producing a glass optical element, wherein a glass material having a concentration of 0 ppm or less is charged and pressure-molded in a softened state by heating. 6. At least a molding surface of silicon carbide and / or
Or use a mold composed of a material containing silicon nitride as a main component and further forming a thin film for preventing fusion on the molding surface, and in this mold, the nitrate content is on an oxide basis.
1 to 10% by weight obtained by melting a glass raw material,
A method for producing a glass optical element, wherein a glass material having a transition point of 530 ° C. or less and a sag point of 565 ° C. or less and containing no PbO as a glass component is put in, and pressure-molded in a heated and softened state. 7. The anti-fusing thin film is at least one selected from the group consisting of carbon, platinum alloy, titanium, titanium carbide, titanium nitride, chromium, chromium carbide, chromium nitride, boron nitride, silicon carbide and silicon nitride. characterized in that it is a single-layer film or a multilayer film made of One material claims 1-6 Neu
2. The method according to claim 1 . 8. The carbon as the fusion-preventing thin film is a carbon composed of an amorphous and / or crystalline single-component layer or a mixed layer having a graphite structure and / or a diamond structure, and a C—H bond. The method according to claim 7 , wherein the compound has a C—H bond and / or has no C—H bond. 9. A platinum alloy as a fusion preventing thin film is made of P
t-Rh alloy, Pt-Rh-Au alloy and Pt-Rh
The method of claim 7 , wherein the method is selected from the group of -Au-Ir alloys. 10. The glass material contains 28 to 55% by weight of SiO ₂ and 5 to 30% by weight of B ₂ O ₃ as glass components, and the total amount of SiO ₂ and B ₂ O ₃ is 46 to 70%. The method according to any one of claims 1 to 9 , wherein the borosilicate glass has a value of SiO ₂ / B ₂ O ₃ of 1.3 to 12.0 (weight ratio). 11. Glass material, further as a glass component, the Li ₂ O 5 to 12 wt%, 0-5% of Na ₂ O by weight, K ₂ O 0 to 5 _{wt%, Li 2 O + Na 2} O + K 2 O: 5 to 12% by weight, BaO: 0 to 40% by weight, MgO: 0 to 10% by weight, CaO: 0 to 23% by weight, SrO: 0 to 20% by weight, ZnO: 0 to 20% by weight, BaO + MgO + CaO + SrO + ZnO 10-44
The method according to claim 10 , comprising at least 72% by weight of SiO ₂ + B ₂ O ₃ + Li ₂ O + BaO + CaO. 12. The method according to claim 11 , comprising 10 to 40% by weight of BaO. 13. The glass material further comprises, as glass components, ₁ to 7.5% by weight of Al ₂ O ₃ , 0 to 3% by weight of P ₂ O ₅ , 0 to 15% by weight of La ₂ O ₃ , Y the ₂ O ₃ 0 to 5 wt%, the Gd ₂ O ₃ 0 to 5 wt%, the TiO ₂ 0-3 wt%, Nb ₂ O ₅ 0 to 3 wt%, the ZrO ₂ 0 to 5 wt%, _{la 2 O 3 + Y 2 O} 3 + Gd 2 method according to any one of claims 10 to 12 O _3, containing 1-15 wt%. 14. The glass material is the glass molding is, a molten glass obtained by outflow from the outflow pipe of a glass melting furnace, consisting of a preform of a predetermined weight of the bulk, claim 1-13 Item 1. The 15. falling to molten glass, subjected by floating on saucer jetted gas from inside, according to claim 14
The method described in.