WO2016129470A1 - Optical glass and method for producing same - Google Patents

Optical glass and method for producing same Download PDF

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Publication number
WO2016129470A1
WO2016129470A1 PCT/JP2016/053187 JP2016053187W WO2016129470A1 WO 2016129470 A1 WO2016129470 A1 WO 2016129470A1 JP 2016053187 W JP2016053187 W JP 2016053187W WO 2016129470 A1 WO2016129470 A1 WO 2016129470A1
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glass
content
optical glass
refractive index
raw material
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PCT/JP2016/053187
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French (fr)
Japanese (ja)
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朋子 山田
太志 鈴木
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日本電気硝子株式会社
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    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C3/00—Glass compositions
    • C03C3/12—Silica-free oxide glass compositions
    • C03C3/14—Silica-free oxide glass compositions containing boron
    • C03C3/15—Silica-free oxide glass compositions containing boron containing rare earths
    • C03C3/155—Silica-free oxide glass compositions containing boron containing rare earths containing zirconium, titanium, tantalum or niobium
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B1/00—Optical elements characterised by the material of which they are made; Optical coatings for optical elements

Definitions

  • the present invention relates to an optical glass, and more particularly to an optical glass having a high refractive index characteristic.
  • the content of SiO 2 and B 2 O 3 which are glass skeleton components is reduced, and rare earth oxides such as La 2 O 3 , Gd 2 O 3 and Ta 2 O 5 are used. or it is necessary to contain a large amount of Nb 2 O 5 and TiO 2. In this case, however, vitrification becomes difficult. This is because optical glass is generally produced by melting and cooling the raw material in a melting vessel such as a crucible, and in a glass system with a small glass skeleton component, crystallization starts from the contact interface with the melting vessel. It is because it becomes easy to progress.
  • a containerless solidification method (a containerless floating method) in which a raw material is melted and cooled in a suspended state is known.
  • a containerless solidification method a containerless floating method in which a raw material is melted and cooled in a suspended state.
  • this method since the molten glass hardly comes into contact with the melting vessel, crystallization starting from the interface with the melting vessel can be prevented, and vitrification becomes possible.
  • Patent Document 1 a glass containing only TiO 2 and BaO as a glass composition is produced by a containerless solidification method.
  • Patent Document 1 Since the glass described in Patent Document 1 is relatively easily devitrified, it is difficult to increase the diameter (for example, the minor axis is 2 mm or more) even when the containerless solidification method is used.
  • an object of the present invention is to provide a novel optical glass that has a high refractive index and can be easily increased in diameter.
  • the optical glass of the present invention contains, in mol%, TiO 2 40 to 85% (excluding 40%), La 2 O 3 10 to 40% (excluding 10% and 40%), Nb 2 O 5 It is characterized by containing 0 to 40% (excluding 0%).
  • the optical glass of the present invention further contains, in mol%, Ta 2 O 5 0-20%, ZrO 2 0-30%, Gd 2 O 3 0-20%, Y 2 O 3 0-20%, or Yb 2. It is preferable to contain 0 to 20% of O 3 .
  • the optical glass of the present invention preferably has a refractive index (nd) of 2.23 to 2.35.
  • the optical glass of the present invention has, for example, a spherical shape or a spheroid shape.
  • the minor axis is preferably 2 mm or more.
  • the optical glass manufacturing method of the present invention is a method for manufacturing the optical glass described above, and in a state where the glass raw material is suspended and held, the glass raw material is heated and melted to obtain a molten glass, and then melted. A step of cooling the glass is provided.
  • the optical glass of the present invention contains, in mol%, TiO 2 40 to 85% (excluding 40%), La 2 O 3 10 to 40% (excluding 10% and 40%), Nb 2 O 5 It is characterized by containing 0 to 40% (excluding 0%). The reason for limiting the glass composition range in this way will be described below. In the following description of the content of each component, “%” means “mol%” unless otherwise specified. "
  • TiO 2 is a component having a large effect of increasing the refractive index, and also has an effect of increasing chemical durability.
  • the content of TiO 2 is 40 to 85% (but not including 40%), preferably 41 to 80%, more preferably 42 to 79%. When the content of TiO 2 is too small, the effect is difficult to obtain. On the other hand, when the content of TiO 2 is too large, it tends to be devitrified. As a result, it tends to be difficult to increase the diameter.
  • La 2 O 3 is a component that increases the refractive index. It also has the effect of improving weather resistance.
  • the content of La 2 O 3 is 10 to 40% (however, 10% and 40% are not included), preferably 16 to 30%, more preferably 18 to 29%. When the content of La 2 O 3 is too small, the effect is difficult to obtain. On the other hand, when the content of La 2 O 3 is too large, it is difficult to vitrify.
  • Nb 2 O 5 is a component having a large effect of increasing the refractive index, and also has an effect of expanding the vitrification range.
  • the content of Nb 2 O 5 is preferably 0 to 40% (however, not including 0%), more preferably 3.1 to 40%, and further preferably 5 to 40%. When Nb 2 O 5 is not contained, the above effect is hardly obtained. On the other hand, when the content of Nb 2 O 5 is too large, it is difficult to vitrify.
  • the optical glass of the present invention may contain Ta 2 O 5 , Gd 2 O 3 , ZrO 2 , Y 2 O 3 or Yb 2 O 3 in addition to the above components. By introducing these components, a glass having desired optical properties can be easily produced.
  • Ta 2 O 5 is a component having a large effect of increasing the refractive index, and also has an effect of increasing chemical durability.
  • the content of Ta 2 O 5 is 0 to 20%, preferably 0 to 15%.
  • ZrO 2 is a component that increases the refractive index and also has the effect of increasing chemical durability. However, when the content of ZrO 2 is too large, it is difficult to vitrify. Therefore, the content of ZrO 2 is preferably 0-30%, more preferably 3-20%.
  • Gd 2 O 3 is a component that increases the refractive index. However, if the content of Gd 2 O 3 is too large, it is difficult to vitrify. Therefore, the content of Gd 2 O 3 is preferably 0 to 20%, more preferably 0 to 15%.
  • Y 2 O 3 is a component that increases the refractive index.
  • the content of Y 2 O 3 is preferably 0 to 20%, more preferably 0 to 15%.
  • Yb 2 O 3 is a component that increases the refractive index.
  • the content of Yb 2 O 3 is preferably 0 to 20%, more preferably 0 to 15%.
  • the optical glass of the present invention can contain the following components.
  • Al 2 O 3 is a component that forms a glass skeleton and widens the vitrification range.
  • the content of Al 2 O 3 is 0 to 20%, preferably 0 to 10%.
  • SiO 2 becomes a glass skeleton and is a component that widens the vitrification range. It also has the effect of improving weather resistance. However, when the content of SiO 2 is too large, the refractive index is hardly desired optical characteristics can be obtained by reduction. Therefore, the content of SiO 2 is 0 to 10%, preferably 0 to 5%.
  • B 2 O 3 becomes a glass skeleton and is a component that widens the vitrification range.
  • the content of B 2 O 3 is 0 to 10%, preferably 0 to 5%.
  • GeO 2 is a component that increases the refractive index and has the effect of expanding the vitrification range.
  • the content of GeO 2 is preferably 0 to 20%, more preferably 0 to 10%.
  • WO 3 has the effect of increasing the refractive index. Moreover, since a glass skeleton is formed as an intermediate oxide, there is an effect of widening the vitrification range. However, when the content of WO 3 is too large, there is a tendency that a large diameter becomes difficult to be devitrified. Therefore, the content of WO 3 is preferably 0 to 10%, more preferably 0 to 5%.
  • SnO 2 is a component having a large effect of increasing the refractive index. However, it is easily reduced and causes coloring. Accordingly, the SnO 2 content is preferably 0 to 5%, more preferably 0 to 3%.
  • P 2 O 5 is a component constituting a glass skeleton and has an effect of extending the vitrification range.
  • the content of P 2 O 5 is preferably 0 to 10%, more preferably 0 to 3%.
  • the content of these components is preferably 0 to 10%, more preferably 0 to 5%.
  • Li 2 O, Na 2 O, K 2 O and Cs 2 O have an effect of lowering the melting temperature, but in order to lower the refractive index, the total amount is preferably 0 to 10%, and 0 to 5% It is more preferable that
  • Sb 2 O 3 can be contained as a fining agent.
  • the content of Sb 2 O 3 is preferably 0.1% or less, more preferably substantially not contained, in order to avoid coloring or in consideration of environmental aspects.
  • PbO is not substantially contained in consideration of environmental load.
  • substantially does not contain means that it is not intentionally contained as a raw material, and does not exclude even inevitable contamination. More objectively, it means that the content is less than 0.1%.
  • the refractive index of the optical glass of the present invention is preferably 2.23 or more, more preferably 2.25 or more.
  • the lens can be made thinner as the refractive index is increased, which is advantageous for downsizing the optical device.
  • the upper limit of the refractive index is preferably 2.35 or less, more preferably 2.33 or less, considering the vitrification stability.
  • the Abbe number is not particularly limited, and may be appropriately adjusted within a range of 10 to 23, for example.
  • the optical glass of the present invention has, for example, a spherical shape or a spheroid shape.
  • the minor axis is 2 mm or more, 2.5 mm or more, particularly 3 mm or more. By doing so, it becomes easy to apply as an optical element such as a lens.
  • FIG. 1 is a schematic cross-sectional view showing an example of a production apparatus for producing a glass material by a containerless solidification method.
  • FIG. 1 is a schematic cross-sectional view showing an example of a production apparatus for producing a glass material by a containerless solidification method.
  • the manufacturing method of the optical glass of this invention is demonstrated, referring FIG.
  • the glass material manufacturing apparatus 1 has a mold 10.
  • the mold 10 also serves as a melting container.
  • the molding die 10 has a molding surface 10a and a plurality of gas ejection holes 10b opened in the molding surface 10a.
  • the gas ejection hole 10b is connected to a gas supply mechanism 11 such as a gas cylinder. Gas is supplied from the gas supply mechanism 11 to the molding surface 10a via the gas ejection hole 10b.
  • the type of gas is not particularly limited, and may be air or oxygen, or an inert gas such as nitrogen gas, argon gas, or helium gas.
  • the glass raw material lump 12 prepared so that it may become glass of the said composition is first arrange
  • the glass raw material block 12 for example, a raw material powder integrated by press molding or the like, a sintered body obtained by integrating the raw material powder by press molding or the like, and a composition equivalent to the target glass composition are used. For example, an aggregate of crystals.
  • the glass raw material block 12 is floated on the molding surface 10a by ejecting gas from the gas ejection holes 10b. That is, the glass raw material block 12 is held in a state where it is not in contact with the molding surface 10a. In this state, the glass material block 12 is irradiated with laser light from the laser light irradiation device 13. Thereby, the glass raw material lump 12 is heated and melted to be vitrified to obtain molten glass. Thereafter, the glass material can be obtained by cooling the molten glass.
  • the method of heating and melting may be radiant heating.
  • Tables 1 to 3 show examples of the present invention and comparative examples, respectively.
  • Each sample was prepared as follows. First, a glass raw material lump was produced using the raw material powder prepared so as to have the glass composition shown in the table.
  • the glass raw material lump was produced by press molding raw material powder and sintering at 1100 to 1400 ° C. for 12 hours.
  • the glass raw material lump was coarsely pulverized using a mortar and used in a state of 0.1 to 0.5 g pieces.
  • a substantially spherical glass material was produced by a containerless solidification method using an apparatus according to FIG.
  • a 100 W CO 2 laser oscillator was used as the heat source.
  • oxygen gas was used as a gas for suspending the glass raw material lump and supplied at a flow rate of 1 to 15 L / min.
  • the refractive index was evaluated by measuring the helium lamp with respect to the d-line (587.6 nm) using a KPR-2000 manufactured by Shimadzu Corporation after bonding a glass material on a 5 mm thick soda plate substrate.

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  • Chemical & Material Sciences (AREA)
  • Materials Engineering (AREA)
  • Chemical Kinetics & Catalysis (AREA)
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  • Life Sciences & Earth Sciences (AREA)
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Abstract

Provided is a novel optical glass having a high refractive index that is easy to increase in diameter. Optical glass characterized by containing, by mol%, TiO2 40-85% (however, not including 40%), La2O3 10-40% (however, not including 10% or 40%), Nb2O5 0-40% (however, not including 0%).

Description

光学ガラス及びその製造方法Optical glass and manufacturing method thereof
　本発明は光学ガラスに関し、特に高屈折率特性を有する光学ガラスに関する。 The present invention relates to an optical glass, and more particularly to an optical glass having a high refractive index characteristic.
　近年、カメラ、顕微鏡及び内視鏡等に用いられる光学系の小型化や軽量化に伴い、使用される光学レンズに用いられるガラスの光学特性として、より高屈折率が求められている。 In recent years, with the reduction in size and weight of optical systems used in cameras, microscopes, endoscopes, and the like, higher refractive indexes are demanded as optical characteristics of glass used in optical lenses used.
　ガラスをより高屈折率にするためには、ガラス骨格成分であるＳｉＯ２やＢ２Ｏ３の含有量を少なくし、Ｌａ２Ｏ３、Ｇｄ２Ｏ３、Ｔａ２Ｏ５等の希土類酸化物またはＮｂ２Ｏ５やＴｉＯ２を多量に含有させる必要がある。しかしながら、この場合ガラス化が困難になる。これは、一般に、光学ガラスは原料を坩堝等の溶融容器内で溶融し、冷却することで作製されるため、ガラス骨格成分が少ないガラス系では、溶融容器との接触界面を起点として結晶化が進行しやすくなるからである。 In order to make the glass have a higher refractive index, the content of SiO 2 and B 2 O 3 which are glass skeleton components is reduced, and rare earth oxides such as La 2 O 3 , Gd 2 O 3 and Ta 2 O 5 are used. or it is necessary to contain a large amount of Nb 2 O 5 and TiO 2. In this case, however, vitrification becomes difficult. This is because optical glass is generally produced by melting and cooling the raw material in a melting vessel such as a crucible, and in a glass system with a small glass skeleton component, crystallization starts from the contact interface with the melting vessel. It is because it becomes easy to progress.
　ガラス化しにくい組成であっても、溶融容器との界面での接触をなくすことによりガラス化が可能となる。このような方法として、原料を浮遊させた状態で溶融、冷却する無容器凝固法（無容器浮遊法）が知られている。当該方法を用いると、溶融ガラスが溶融容器にほとんど接触することがないため、溶融容器との界面を起点とする結晶化を防止することができ、ガラス化が可能となる。例えば、特許文献１では、無容器凝固法により、ガラス組成としてＴｉＯ２とＢａＯのみを含有するガラスが作製されている。 Even if the composition is difficult to vitrify, it can be vitrified by eliminating contact at the interface with the melting vessel. As such a method, a containerless solidification method (a containerless floating method) in which a raw material is melted and cooled in a suspended state is known. When this method is used, since the molten glass hardly comes into contact with the melting vessel, crystallization starting from the interface with the melting vessel can be prevented, and vitrification becomes possible. For example, in Patent Document 1, a glass containing only TiO 2 and BaO as a glass composition is produced by a containerless solidification method.
特許第４７８９０８６号公報Japanese Patent No. 4789086
　特許文献１に記載のガラスは、比較的失透しやすいため、無容器凝固法を用いた場合であっても、大径化（例えば短径２ｍｍ以上）は困難である。 Since the glass described in Patent Document 1 is relatively easily devitrified, it is difficult to increase the diameter (for example, the minor axis is 2 mm or more) even when the containerless solidification method is used.
　以上に鑑み、本発明は、高屈折率であり、かつ大径化が容易である新規な光学ガラスを提供することを目的とする。 In view of the above, an object of the present invention is to provide a novel optical glass that has a high refractive index and can be easily increased in diameter.
　本発明の光学ガラスは、モル％で、ＴｉＯ２　４０～８５％（ただし４０％を含まない）、Ｌａ２Ｏ３　１０～４０％（ただし１０％、４０％を含まない）、Ｎｂ２Ｏ５　０～４０％（ただし０％を含まない）を含有することを特徴とする。 The optical glass of the present invention contains, in mol%, TiO 2 40 to 85% (excluding 40%), La 2 O 3 10 to 40% (excluding 10% and 40%), Nb 2 O 5 It is characterized by containing 0 to 40% (excluding 0%).
　本発明の光学ガラスは、さらに、モル％で、Ｔａ２Ｏ５　０～２０％、ＺｒＯ２　０～３０％、Ｇｄ２Ｏ３　０～２０％、Ｙ２Ｏ３　０～２０％、またはＹｂ２Ｏ３　０～２０％を含有することが好ましい。 The optical glass of the present invention further contains, in mol%, Ta 2 O 5 0-20%, ZrO 2 0-30%, Gd 2 O 3 0-20%, Y 2 O 3 0-20%, or Yb 2. It is preferable to contain 0 to 20% of O 3 .
　本発明の光学ガラスは、屈折率（ｎｄ）が２．２３～２．３５であることが好ましい。 The optical glass of the present invention preferably has a refractive index (nd) of 2.23 to 2.35.
　本発明の光学ガラスは、例えば球形状または回転楕円体形状である。またその場合、短径が２ｍｍ以上であることが好ましい。 The optical glass of the present invention has, for example, a spherical shape or a spheroid shape. In that case, the minor axis is preferably 2 mm or more.
　本発明の光学ガラスの製造方法は、上記の光学ガラスを製造するための方法であって、ガラス原料を浮遊させて保持した状態で、ガラス原料を加熱融解させて溶融ガラスを得た後に、溶融ガラスを冷却する工程を備えることを特徴とする。 The optical glass manufacturing method of the present invention is a method for manufacturing the optical glass described above, and in a state where the glass raw material is suspended and held, the glass raw material is heated and melted to obtain a molten glass, and then melted. A step of cooling the glass is provided.
　本発明によれば、従来よりも高屈折率であり、かつ大径化が容易である新規な光学ガラスを提供することが可能となる。 According to the present invention, it is possible to provide a novel optical glass that has a higher refractive index than conventional ones and can be easily increased in diameter.
本発明の光学ガラスを製造するための装置の一実施形態を示す模式的断面図である。It is typical sectional drawing which shows one Embodiment of the apparatus for manufacturing the optical glass of this invention.
　本発明の光学ガラスは、モル％で、ＴｉＯ２　４０～８５％（ただし４０％を含まない）、Ｌａ２Ｏ３　１０～４０％（ただし１０％、４０％を含まない）、Ｎｂ２Ｏ５　０～４０％（ただし０％を含まない）を含有することを特徴とする。ガラス組成範囲をこのように限定した理由を以下に説明する。なお、以下の各成分の含有量に関する説明において、特に断りのない限り「％」は「モル％」を意味する。」 The optical glass of the present invention contains, in mol%, TiO 2 40 to 85% (excluding 40%), La 2 O 3 10 to 40% (excluding 10% and 40%), Nb 2 O 5 It is characterized by containing 0 to 40% (excluding 0%). The reason for limiting the glass composition range in this way will be described below. In the following description of the content of each component, “%” means “mol%” unless otherwise specified. "
　ＴｉＯ２は屈折率を高める効果が大きい成分であり、化学的耐久性を高める効果もある。ＴｉＯ２の含有量は４０～８５％（ただし４０％を含まない）、好ましくは４１～８０％、より好ましくは４２～７９％である。ＴｉＯ２の含有量が少なすぎると、上記効果が得られにくくなる。一方、ＴｉＯ２の含有量が多すぎると、失透しやすくなる。結果として、大径化が困難になる傾向がある。 TiO 2 is a component having a large effect of increasing the refractive index, and also has an effect of increasing chemical durability. The content of TiO 2 is 40 to 85% (but not including 40%), preferably 41 to 80%, more preferably 42 to 79%. When the content of TiO 2 is too small, the effect is difficult to obtain. On the other hand, when the content of TiO 2 is too large, it tends to be devitrified. As a result, it tends to be difficult to increase the diameter.
　Ｌａ２Ｏ３は屈折率を高める成分である。また、耐候性を向上させる効果もある。Ｌａ２Ｏ３の含有量は１０～４０％（ただし１０％、４０％を含まない）であり、好ましくは１６～３０％、より好ましくは１８～２９％である。Ｌａ２Ｏ３の含有量が少なすぎると、上記効果が得られにくくなる。一方、Ｌａ２Ｏ３の含有量が多すぎると、ガラス化しにくくなる。 La 2 O 3 is a component that increases the refractive index. It also has the effect of improving weather resistance. The content of La 2 O 3 is 10 to 40% (however, 10% and 40% are not included), preferably 16 to 30%, more preferably 18 to 29%. When the content of La 2 O 3 is too small, the effect is difficult to obtain. On the other hand, when the content of La 2 O 3 is too large, it is difficult to vitrify.
　Ｎｂ２Ｏ５は屈折率を高める効果が大きい成分であり、ガラス化範囲を広げる効果もある。Ｎｂ２Ｏ５の含有量は、好ましくは０～４０％（ただし０％を含まない）、より好ましくは３．１～４０％、さらに好ましくは５～４０％である。Ｎｂ２Ｏ５を含有しない場合、上記効果が得られにくくなる。一方、Ｎｂ２Ｏ５の含有量が多すぎると、ガラス化しにくくなる。 Nb 2 O 5 is a component having a large effect of increasing the refractive index, and also has an effect of expanding the vitrification range. The content of Nb 2 O 5 is preferably 0 to 40% (however, not including 0%), more preferably 3.1 to 40%, and further preferably 5 to 40%. When Nb 2 O 5 is not contained, the above effect is hardly obtained. On the other hand, when the content of Nb 2 O 5 is too large, it is difficult to vitrify.
　本発明の光学ガラスには、上記成分以外にも、Ｔａ２Ｏ５、Ｇｄ２Ｏ３、ＺｒＯ２、Ｙ２Ｏ３またはＹｂ２Ｏ３を含有させることができる。これらの成分を導入することで、所望の光学特性を有するガラスを容易に作製することができる。 The optical glass of the present invention may contain Ta 2 O 5 , Gd 2 O 3 , ZrO 2 , Y 2 O 3 or Yb 2 O 3 in addition to the above components. By introducing these components, a glass having desired optical properties can be easily produced.
　Ｔａ２Ｏ５は屈折率を高める効果が大きい成分であり、化学的耐久性を高める効果も有する。ただし、Ｔａ２Ｏ５の含有量が多すぎると、ガラス化しにくくなる。また、原料コストが高くなる傾向がある。従って、Ｔａ２Ｏ５の含有量は０～２０％であり、好ましくは０～１５％である。 Ta 2 O 5 is a component having a large effect of increasing the refractive index, and also has an effect of increasing chemical durability. However, when the content of Ta 2 O 5 is too large, it is difficult to vitrify. In addition, raw material costs tend to be high. Therefore, the content of Ta 2 O 5 is 0 to 20%, preferably 0 to 15%.
　ＺｒＯ２は屈折率を高める成分であり、化学的耐久性を高める効果も有する。ただし、ＺｒＯ２の含有量が多すぎると、ガラス化しにくくなる。従って、ＺｒＯ２の含有量は、好ましくは０～３０％、より好ましくは３～２０％である。 ZrO 2 is a component that increases the refractive index and also has the effect of increasing chemical durability. However, when the content of ZrO 2 is too large, it is difficult to vitrify. Therefore, the content of ZrO 2 is preferably 0-30%, more preferably 3-20%.
　Ｇｄ２Ｏ３は屈折率を高める成分である。ただし、Ｇｄ２Ｏ３の含有量が多すぎると、ガラス化しにくくなる。従って、Ｇｄ２Ｏ３の含有量は、好ましくは０～２０％、より好ましくは０～１５％である。 Gd 2 O 3 is a component that increases the refractive index. However, if the content of Gd 2 O 3 is too large, it is difficult to vitrify. Therefore, the content of Gd 2 O 3 is preferably 0 to 20%, more preferably 0 to 15%.
　Ｙ２Ｏ３は屈折率を高める成分である。ただし、Ｙ２Ｏ３の含有量が多すぎると、ガラス化しにくくなる。従って、Ｙ２Ｏ３の含有量は、好ましくは０～２０％、より好ましくは０～１５％である。 Y 2 O 3 is a component that increases the refractive index. However, when the content of Y 2 O 3 is too large, it is difficult to vitrify. Therefore, the content of Y 2 O 3 is preferably 0 to 20%, more preferably 0 to 15%.
　Ｙｂ２Ｏ３は屈折率を高める成分である。ただし、Ｙｂ２Ｏ３の含有量が多すぎると、ガラス化しにくくなる。また、原料コストが高くなる傾向がある。従って、Ｙｂ２Ｏ３の含有量は、好ましくは０～２０％、より好ましくは０～１５％である。 Yb 2 O 3 is a component that increases the refractive index. However, when the content of Yb 2 O 3 is too large, it is difficult to vitrify. In addition, raw material costs tend to be high. Therefore, the content of Yb 2 O 3 is preferably 0 to 20%, more preferably 0 to 15%.
　本発明の光学ガラスには、上記成分以外にも、以下の成分を含有させることができる。 In addition to the above components, the optical glass of the present invention can contain the following components.
　Ａｌ２Ｏ３はガラス骨格を形成し、ガラス化範囲を広げる成分である。ただし、Ａｌ２Ｏ３の含有量が多すぎると、屈折率が低下して所望の光学特性が得られにくくなる。従って、Ａｌ２Ｏ３の含有量は０～２０％であり、好ましくは０～１０％である。 Al 2 O 3 is a component that forms a glass skeleton and widens the vitrification range. However, when the content of Al 2 O 3 is too large, the refractive index is hardly desired optical characteristics can be obtained by reduction. Therefore, the content of Al 2 O 3 is 0 to 20%, preferably 0 to 10%.
　ＳｉＯ２はガラス骨格となり、ガラス化範囲を広げる成分である。また、耐候性を向上させる効果もある。ただし、ＳｉＯ２の含有量が多すぎると、屈折率が低下して所望の光学特性が得られにくくなる。従って、ＳｉＯ２の含有量は０～１０％であり、好ましくは０～５％である。 SiO 2 becomes a glass skeleton and is a component that widens the vitrification range. It also has the effect of improving weather resistance. However, when the content of SiO 2 is too large, the refractive index is hardly desired optical characteristics can be obtained by reduction. Therefore, the content of SiO 2 is 0 to 10%, preferably 0 to 5%.
　Ｂ２Ｏ３はガラス骨格となり、ガラス化範囲を広げる成分である。ただし、Ｂ２Ｏ３の含有量が多すぎると、屈折率が低下して所望の光学特性が得られにくくなる。従って、Ｂ２Ｏ３の含有量は０～１０％であり、好ましくは０～５％である。 B 2 O 3 becomes a glass skeleton and is a component that widens the vitrification range. However, when the content of B 2 O 3 is too large, desired optical characteristics refractive index is lowered it is difficult to obtain. Therefore, the content of B 2 O 3 is 0 to 10%, preferably 0 to 5%.
　ＧｅＯ２は屈折率を高める成分であり、ガラス化範囲を広げる効果もある。ただし、ＧｅＯ２の含有量が多すぎると、原料コストが高くなる傾向がある。従って、ＧｅＯ２の含有量は、好ましくは０～２０％、より好ましくは０～１０％である。 GeO 2 is a component that increases the refractive index and has the effect of expanding the vitrification range. However, when the content of GeO 2 is too large, the raw material cost tends to increase. Accordingly, the content of GeO 2 is preferably 0 to 20%, more preferably 0 to 10%.
　ＷＯ３は屈折率を高める効果がある。また、中間酸化物としてガラス骨格を形成するため、ガラス化範囲を広げる効果もある。ただし、ＷＯ３の含有量が多すぎると、失透しやすくなり大径化が困難になる傾向がある。従って、ＷＯ３の含有量は、好ましくは０～１０％、より好ましくは０～５％である。 WO 3 has the effect of increasing the refractive index. Moreover, since a glass skeleton is formed as an intermediate oxide, there is an effect of widening the vitrification range. However, when the content of WO 3 is too large, there is a tendency that a large diameter becomes difficult to be devitrified. Therefore, the content of WO 3 is preferably 0 to 10%, more preferably 0 to 5%.
　ＳｎＯ２は屈折率を高める効果が大きい成分である。ただし、還元されやすく着色の原因となる。従って、ＳｎＯ２の含有量は、好ましくは０～５％、より好ましくは０～３％である。 SnO 2 is a component having a large effect of increasing the refractive index. However, it is easily reduced and causes coloring. Accordingly, the SnO 2 content is preferably 0 to 5%, more preferably 0 to 3%.
　Ｐ２Ｏ５はガラス骨格を構成する成分であり、ガラス化範囲を広げる効果がある。ただし、その含有量が多すぎると、分相しやすくなる。従って、Ｐ２Ｏ５の含有量は、好ましくは０～１０％、より好ましくは０～３％である。 P 2 O 5 is a component constituting a glass skeleton and has an effect of extending the vitrification range. However, when the content is too large, phase separation tends to occur. Therefore, the content of P 2 O 5 is preferably 0 to 10%, more preferably 0 to 3%.
　ＺｎＯ、ＭｇＯ、ＣａＯ、ＳｒＯ及びＢａＯはガラス化を安定にしたり、化学的耐久性を高める効果がある。ただし、その含有量が多すぎると、屈折率が低下して所望の光学特性が得られにくくなる。従って、これらの成分の含有量は、それぞれ好ましくは０～１０％、より好ましくは０～５％である。 ZnO, MgO, CaO, SrO and BaO are effective in stabilizing vitrification and improving chemical durability. However, if the content is too large, the refractive index is lowered and it becomes difficult to obtain desired optical characteristics. Accordingly, the content of these components is preferably 0 to 10%, more preferably 0 to 5%.
　Ｌｉ２Ｏ、Ｎａ２Ｏ、Ｋ２Ｏ及びＣｓ２Ｏは溶融温度を低下させる効果があるが、屈折率を低下させるため、合量で０～１０％であることが好ましく、０～５％であることがより好ましい。 Li 2 O, Na 2 O, K 2 O and Cs 2 O have an effect of lowering the melting temperature, but in order to lower the refractive index, the total amount is preferably 0 to 10%, and 0 to 5% It is more preferable that
　清澄剤としてＳｂ２Ｏ３を含有させることができる。ただし、着色を避けるため、あるいは環境面を考慮して、Ｓｂ２Ｏ３の含有量は０．１％以下であることが好ましく、実質的に含有しないことがより好ましい。 Sb 2 O 3 can be contained as a fining agent. However, the content of Sb 2 O 3 is preferably 0.1% or less, more preferably substantially not contained, in order to avoid coloring or in consideration of environmental aspects.
　ＰｂＯは環境への負荷を考慮し、実質的に含有しないことが好ましい。 It is preferable that PbO is not substantially contained in consideration of environmental load.
　なお、本発明において「実質的に含有しない」とは、意図的に原料として含有させないことを意味し、不可避的不純物の混入までをも排除するものではない。より客観的には、含有量が０．１％未満であることを意味する。 In the present invention, “substantially does not contain” means that it is not intentionally contained as a raw material, and does not exclude even inevitable contamination. More objectively, it means that the content is less than 0.1%.
　本発明の光学ガラスの屈折率は、好ましくは２．２３以上、より好ましくは２．２５以上である。例えば、本発明の光学ガラスをレンズとして使用する場合、屈折率を高めるほどレンズを薄くすることが可能となり、光学デバイスを小型化する上で有利となる。なお、屈折率の上限は、ガラス化の安定性を考慮して、好ましくは２．３５以下、より好ましくは２．３３以下である。 The refractive index of the optical glass of the present invention is preferably 2.23 or more, more preferably 2.25 or more. For example, when the optical glass of the present invention is used as a lens, the lens can be made thinner as the refractive index is increased, which is advantageous for downsizing the optical device. The upper limit of the refractive index is preferably 2.35 or less, more preferably 2.33 or less, considering the vitrification stability.
　本発明の光学ガラスにおいてアッベ数は特に限定されず、例えば１０～２３の範囲で適宜調整される。 In the optical glass of the present invention, the Abbe number is not particularly limited, and may be appropriately adjusted within a range of 10 to 23, for example.
　本発明の光学ガラスは、例えば球形状や回転楕円体形状を有する。その場合、短径が２ｍｍ以上、２．５ｍｍ以上、特に３ｍｍ以上であることが好ましい。そのようにすれば、レンズ等の光学素子として適用しやすくなる。 The optical glass of the present invention has, for example, a spherical shape or a spheroid shape. In that case, it is preferable that the minor axis is 2 mm or more, 2.5 mm or more, particularly 3 mm or more. By doing so, it becomes easy to apply as an optical element such as a lens.
　本発明の光学ガラスは例えば無容器凝固法により作製することができる。図１は、無容器凝固法によりガラス材を作製するための製造装置の一例を示す模式的断面図である。以下、図１を参照しながら、本発明の光学ガラスの製造方法について説明する。 The optical glass of the present invention can be produced, for example, by a containerless solidification method. FIG. 1 is a schematic cross-sectional view showing an example of a production apparatus for producing a glass material by a containerless solidification method. Hereafter, the manufacturing method of the optical glass of this invention is demonstrated, referring FIG.
　ガラス材の製造装置１は成形型１０を有する。成形型１０は溶融容器としての役割も果たす。成形型１０は、成形面１０ａと、成形面１０ａに開口している複数のガス噴出孔１０ｂとを有する。ガス噴出孔１０ｂは、ガスボンベなどのガス供給機構１１に接続されている。このガス供給機構１１からガス噴出孔１０ｂを経由して、成形面１０ａにガスが供給される。ガスの種類は特に限定されず、例えば、空気や酸素であってもよいし、窒素ガス、アルゴンガス、ヘリウムガス等の不活性ガスであってもよい。 The glass material manufacturing apparatus 1 has a mold 10. The mold 10 also serves as a melting container. The molding die 10 has a molding surface 10a and a plurality of gas ejection holes 10b opened in the molding surface 10a. The gas ejection hole 10b is connected to a gas supply mechanism 11 such as a gas cylinder. Gas is supplied from the gas supply mechanism 11 to the molding surface 10a via the gas ejection hole 10b. The type of gas is not particularly limited, and may be air or oxygen, or an inert gas such as nitrogen gas, argon gas, or helium gas.
　製造装置１を用いてガラス材を製造するに際しては、まず、上記組成のガラスとなるように調製したガラス原料塊１２を成形面１０ａ上に配置する。ガラス原料塊１２としては、例えば、原料粉末をプレス成形等により一体化したものや、原料粉末をプレス成形等により一体化した後に焼結させた焼結体や、目標ガラス組成と同等の組成を有する結晶の集合体等が挙げられる。 When manufacturing a glass material using the manufacturing apparatus 1, the glass raw material lump 12 prepared so that it may become glass of the said composition is first arrange | positioned on the molding surface 10a. As the glass raw material block 12, for example, a raw material powder integrated by press molding or the like, a sintered body obtained by integrating the raw material powder by press molding or the like, and a composition equivalent to the target glass composition are used. For example, an aggregate of crystals.
　次に、ガス噴出孔１０ｂからガスを噴出させることにより、ガラス原料塊１２を成形面１０ａ上で浮遊させる。すなわち、ガラス原料塊１２を、成形面１０ａに接触していない状態で保持する。その状態で、レーザー光照射装置１３からレーザー光をガラス原料塊１２に照射する。これによりガラス原料塊１２を加熱溶融してガラス化させ、溶融ガラスを得る。その後、溶融ガラスを冷却することにより、ガラス材を得ることができる。ガラス原料塊１２を加熱溶融する工程と、溶融ガラス、さらにはガラス材の温度が少なくとも軟化点以下となるまで冷却する工程とにおいては、少なくともガスの噴出を継続し、ガラス原料塊１２、溶融ガラス、さらにはガラス材と成形面１０ａとの接触を抑制することが好ましい。なお、加熱溶融する方法としては、レーザー光を照射する方法以外にも、輻射加熱であってもよい。 Next, the glass raw material block 12 is floated on the molding surface 10a by ejecting gas from the gas ejection holes 10b. That is, the glass raw material block 12 is held in a state where it is not in contact with the molding surface 10a. In this state, the glass material block 12 is irradiated with laser light from the laser light irradiation device 13. Thereby, the glass raw material lump 12 is heated and melted to be vitrified to obtain molten glass. Thereafter, the glass material can be obtained by cooling the molten glass. In the step of heating and melting the glass raw material lump 12 and the step of cooling until the temperature of the molten glass and further the glass material becomes at least the softening point or less, at least gas ejection is continued, and the glass raw material lump 12 and the molten glass Furthermore, it is preferable to suppress contact between the glass material and the molding surface 10a. In addition to the method of irradiating with laser light, the method of heating and melting may be radiant heating.
　以下、本発明を実施例に基づいて説明するが、本発明はこれらの実施例に限定されるものではない。 Hereinafter, the present invention will be described based on examples, but the present invention is not limited to these examples.
　表１～３は本発明の実施例及び比較例をそれぞれ示している。 Tables 1 to 3 show examples of the present invention and comparative examples, respectively.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
　各試料は次のようにして調製した。まず表に示すガラス組成になるように調合した原料粉末を用いてガラス原料塊を作製した。ガラス原料塊は、原料粉末をプレス成型して１１００～１４００℃で１２時間焼結する方法により作製した。なお、ガラス原料塊は、乳鉢を用いて粗粉砕し、０．１～０．５ｇの小片にした状態で用いた。 Each sample was prepared as follows. First, a glass raw material lump was produced using the raw material powder prepared so as to have the glass composition shown in the table. The glass raw material lump was produced by press molding raw material powder and sintering at 1100 to 1400 ° C. for 12 hours. The glass raw material lump was coarsely pulverized using a mortar and used in a state of 0.1 to 0.5 g pieces.
　上記で得られたガラス原料塊を用いて、図１に準じた装置を用いた無容器凝固法によって略球形状のガラス材を作製した。なお、熱源としては１００Ｗ　ＣＯ２レーザー発振器を用いた。また、ガラス原料塊を浮遊させるためのガスとして酸素ガスを用い、流量１～１５Ｌ／ｍｉｎで供給した。 Using the glass raw material block obtained above, a substantially spherical glass material was produced by a containerless solidification method using an apparatus according to FIG. A 100 W CO 2 laser oscillator was used as the heat source. In addition, oxygen gas was used as a gas for suspending the glass raw material lump and supplied at a flow rate of 1 to 15 L / min.
　得られたガラス材について、屈折率（ｎｄ）及びアッベ数（νｄ）を測定した。結果を表１～３に示す。 The refractive index (nd) and Abbe number (νd) of the obtained glass material were measured. The results are shown in Tables 1 to 3.
　屈折率は、ガラス材を厚さ５ｍｍのソーダ板基板上に接着後、直角研磨を行い、島津製作所製ＫＰＲ－２０００用いて、ヘリウムランプのｄ線（５８７．６ｎｍ）に対する測定値で評価した。 The refractive index was evaluated by measuring the helium lamp with respect to the d-line (587.6 nm) using a KPR-2000 manufactured by Shimadzu Corporation after bonding a glass material on a 5 mm thick soda plate substrate.
　アッベ数は上記ｄ線に対する屈折率と、水素ランプのＦ線（４８６．１ｎｍ）及びＣ線（６５６．３ｎｍ）に対する屈折率の値を用い、アッベ数（νｄ）＝｛（ｎｄ－１）／（ｎＦ－ｎＣ）｝の式から算出した。 The Abbe number uses the refractive index for the d-line and the refractive index values for the F-line (486.1 nm) and C-line (656.3 nm) of the hydrogen lamp, and the Abbe number (νd) = {(nd−1) / It was calculated from the equation (nF-nC)}.
　表１及び２に示すように、実施例１～１２では、屈折率が２．２７０７１～２．３２４８６と高く、短径が２．７～４．４ｍｍと大きい試料が得られた。 As shown in Tables 1 and 2, in Examples 1 to 12, samples having a high refractive index of 2.27071 to 2.33486 and a short axis of 2.7 to 4.4 mm were obtained.
　一方、表３に示すように、比較例１～４の試料はガラス化しなかった。また、比較例５の試料は屈折率が２．２２４８３と低かった。 On the other hand, as shown in Table 3, the samples of Comparative Examples 1 to 4 were not vitrified. Further, the sample of Comparative Example 5 had a low refractive index of 2.22483.
１：ガラス材の製造装置
１０：成形型
１０ａ：成形面
１０ｂ：ガス噴出孔
１１：ガス供給機構
１２：ガラス原料塊
１３：レーザー光照射装置 1: Glass material manufacturing apparatus 10: Mold 10a: Molding surface 10b: Gas ejection hole 11: Gas supply mechanism 12: Glass raw material block 13: Laser beam irradiation apparatus

Claims (6)

  1. 　モル％で、ＴｉＯ２　４０～８５％（ただし４０％を含まない）、Ｌａ２Ｏ３　１０～４０％（ただし１０％、４０％を含まない）、Ｎｂ２Ｏ５　０～４０％（ただし０％を含まない）を含有することを特徴とする光学ガラス。 TiO 2 40 to 85% (excluding 40%), La 2 O 3 10 to 40% (excluding 10% and 40%), Nb 2 O 5 0 to 40% (excluding 0%) % Glass). An optical glass comprising:
  2. 　さらに、モル％で、Ｔａ２Ｏ５　０～２０％、ＺｒＯ２　０～３０％、Ｇｄ２Ｏ３　０～２０％、Ｙ２Ｏ３　０～２０％、またはＹｂ２Ｏ３　０～２０％を含有することを特徴とする請求項１に記載の光学ガラス。 Further, in mole percent, Ta 2 O 5 0-20%, ZrO 2 0-30%, Gd 2 O 3 0-20%, Y 2 O 3 0-20%, or Yb 2 O 3 0-20% The optical glass according to claim 1, which is contained.
  3. 　屈折率（ｎｄ）が２．２３～２．３５であることを特徴とする請求項１または２に記載の光学ガラス。 3. The optical glass according to claim 1, wherein the refractive index (nd) is 2.23 to 2.35.
  4. 　球形状または回転楕円体形状であることを特徴とする請求項１～３のいずれか一項に記載の光学ガラス。 The optical glass according to any one of claims 1 to 3, which has a spherical shape or a spheroid shape.
  5. 　短径が２ｍｍ以上であることを特徴とする請求項４に記載の光学ガラス。 The optical glass according to claim 4, wherein the minor axis is 2 mm or more.
  6. 　請求項１～５のいずれか一項に記載の光学ガラスを製造するための方法であって、
    　ガラス原料を浮遊させて保持した状態で、前記ガラス原料を加熱融解させて溶融ガラスを得た後に、前記溶融ガラスを冷却する工程を備えることを特徴とする、光学ガラスの製造方法。     A method for producing the optical glass according to any one of claims 1 to 5,
    An optical glass manufacturing method comprising a step of cooling the molten glass after the glass raw material is heated and melted to obtain molten glass in a state where the glass raw material is suspended and held.
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