JP2011140434A - Optical glass, optical element and preform - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide optical glass having high refractive index and high dispersibility, a small partial dispersion ratio and good transmittance. <P>SOLUTION: The optical glass contains by mol%, in terms of oxide, 10.0-60.0% P<SB>2</SB>O<SB>5</SB>component, 10.0-45.0% Nb<SB>2</SB>O<SB>5</SB>component and 0-30.0% TiO<SB>2</SB>component per the quantity of glass total substance, wherein the partial dispersion ratio (θ<SB>g</SB>, F) and abbe number (ν<SB>d</SB>) satisfies a relationship; (-0.0016×ν<SB>d</SB>+0.63460)≤(θ<SB>g</SB>, F)≤(-0.00563×ν<SB>d</SB>+0.75873) in the range of ν<SB>d</SB>≤25, and further satisfies a relationship; (-0.0025×ν<SB>d</SB>+0.65710)≤(θ<SB>g</SB>, F)≤(-0.0034×ν<SB>d</SB>+0.70300) in the range of (ν<SB>d</SB>)>25. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an optical glass, an optical element, and a preform.

High refractive index and high dispersion glass is in great demand as a material for optical elements such as various lenses. For example, in Patent Documents 1 to 3, the refractive index (n _d ) is 1.78 or more and the Abbe number (ν _d ). Describes an optical glass having a thickness of 30 or less.

  An optical system in which these optical glasses are used is mounted on an optical product such as a digital camera. However, in order to improve chromatic aberration, it is desirable that the optical glass in the high refractive index and high dispersion region has a small partial dispersion ratio.

  Conventionally, high refractive index and high dispersion glass has a tendency to deteriorate the light transmittance (coloring degree) in the visible region.

JP-A-52-25812 JP 2004-161598 A International Publication No. 2004/110942 Pamphlet

An object of the present invention is to solve the problems in the conventional optical glass as described above.
That is, an object of the present invention is to provide an optical glass having a high refractive index and a high dispersibility, a small partial dispersion ratio, and a good transmittance.

The inventor has intensively studied to solve the above-mentioned problems, and has completed the present invention.
The present invention includes the following (1) to (8).
(1) the glass the total amount of substance of the oxide composition in terms of, in mole _percent, from 10.0 to 60.0% of P 2 _{O 5} component, 10.0 to 45.0% of _Nb 2 _{O 5} component, Containing 0 to 30.0% of TiO ₂ component,
Between the partial dispersion ratio (θg, F) and the Abbe number (ν _d ),
In the range of ν _d ≦ 25, the relationship of (−0.0016 × ν _d +0.63460) ≦ (θg, F) ≦ (−0.00563 × ν _d +0.75873) is satisfied,
Optical glass satisfying the relationship of (−0.0025 × ν _d +0.65710) ≦ (θg, F) ≦ (−0.0034 × ν _d +0.70300) in the range of ν _d > 25.
₍₂₎ B comprises a 2 _{O 3,} the optical glass according to the above (1).
(3) The optical glass according to (1) or 2 above, which contains B ₂ O ₃ component in an amount of more than 0% and 10.4% or less.
(4) SiO ₂ component 0 to 30.0% in mol% with respect to the total amount of glass in oxide-converted composition
GeO ₂ component 0 to 20.0%
TeO ₂ component 0 to 20.0%
Li ₂ O component 0 to 30.0%
Na ₂ O component 0-40.0%
K ₂ O component 0 to 25.0%
Cs ₂ O component 0 to 20.0%
MgO component 0 to 15.0%
CaO component 0 to 20.0%
SrO component 0 to 20.0%
BaO component 0 to 30.0%
ZnO component 0 to 30.0%
Al ₂ O ₃ component 0 to 20.0%
ZrO ₂ component 0 to 20.0%
WO ₃ component 0 to 20.0%
Bi ₂ O ₃ component 0 to 20.0%
La ₂ O ₃ component 0 to 20.0%
Gd ₂ O ₃ component 0 to 20.0%
Y ₂ O ₃ component 0 to 20.0%
Ta ₂ O ₅ component 0 to 20.0%
In ₂ O ₃ component 0 to 20.0%
Yb ₂ O ₃ component 0 to 20.0%
CeO ₂ component 0-1.0%
Sb ₂ O ₃ component 0 to 1.0% in an externally added amount (mol%) with respect to the total amount of glass of oxide conversion composition
Optical glass in any one of said (1)-(3) which further contains each component of.
(5) Wavelength (λ ₇₀ ) having a refractive index (n _d ) of 1.70 to 2.00, an Abbe number (ν _d ) of 15 to 35 and a spectral transmittance of 70% Optical glass in any one of said (1)-(4) whose is 500 nm or less.
(6) An optical element obtained by grinding and polishing the optical glass according to any one of (1) to (5).
(7) An optical element obtained by precision press-molding the optical glass according to any one of (1) to (5) above.
(8) A precision press-molding preform comprising the optical glass according to any one of (1) to (5) above.

  According to the present invention, an optical glass having a high refractive index and a high dispersibility, a small partial dispersion ratio, and a good transmittance can be provided.

The present invention will be described.
The present invention, the glass the total amount of substance of the oxide composition in terms of, in mole percent, from 10.0 to 60.0% of P ₂ O ₅ component, a Nb ₂ O ₅ component from 10.0 to 45.0% The TiO ₂ component is contained in an amount of 0 to 30.0%, and the partial dispersion ratio (θg, F) is in the range of ν _d ≦ 25 with respect to the Abbe number (ν _d ) in the relationship of the following formula (1) And an optical glass that satisfies the relationship of the following formula (2) in the range of ν _d > 25.
Formula (1) ... (− 0.0016 × ν _d +0.63460) ≦ (θg, F) ≦ (−0.00563 × ν _d +0.75873)
Formula (2) ... (− 0.0025 × ν _d +0.65710) ≦ (θg, F) ≦ (−0.0034 × ν _d +0.70300)
Hereinafter, such an optical glass is also referred to as “optical glass of the present invention”.

Each component of the optical glass of the present invention will be described.
Hereinafter, unless otherwise specified, the content (%) of each component means mol% based on oxide.

The P ₂ O ₅ component is an important component as a glass-forming oxide and an effective component for imparting high dispersibility to the glass. The P ₂ O ₅ component is 10.0%, preferably 15.0%, more preferably 17.0%, more preferably 18.0%, more preferably 19.0%, more preferably 20.0%, More preferably 21.0%, still more preferably 21.3%, most preferably 22.0% can be contained as a lower limit, 60.0%, preferably 50.0%, more preferably 40.0%. %, More preferably 38.0%, more preferably 35.0%, still more preferably 31.0%. For example, 10.0 to 60.0% is preferable, 15.0 to 40.0% is more preferable, 17.0 to 35.0% is more preferable, and 21.35 to 35. More preferably, it is 0.0%.
The P ₂ O ₅ component can be contained in the glass using, for example, orthophosphoric acid, phosphate, or the like as a raw material.

The Nb ₂ O ₅ component is an essential component effective for increasing the refractive index, decreasing the partial dispersion ratio while increasing the dispersion, and improving the chemical durability and devitrification resistance. However, if the amount is too small, the effect becomes insufficient. On the other hand, if the amount is too large, the devitrification resistance is deteriorated, and the transmittance in the visible light short wavelength region is likely to be deteriorated. Accordingly, 10.0%, preferably 15.0%, more preferably 20.0%, more preferably 24.0%, more preferably 25.0%, more preferably 26.0%, more preferably 27 0.05%, more preferably 27.5% can be contained as a lower limit, and 45.0%, preferably 40.0%, more preferably 35.0%, more preferably 32.0%, still more preferably Can contain up to 31.0. For example, 26.0 to 45.0% is preferable, 27.0 to 45.0% is preferable, and 27.5 to 33.0% is more preferable.
The Nb ₂ O ₅ component can be contained in the glass using, for example, Nb ₂ O ₅ as a raw material.

It is preferable that the content of the P ₂ O ₅ component is 21.3% or more and the content of the Nb ₂ O ₅ component is 27.5% or more.

The TiO ₂ component has the effect of increasing the partial dispersion ratio while increasing the refractive index and increasing the dispersion. However, if the amount is too large, the transmittance in the visible light short wavelength region is deteriorated. Therefore, 30.0%, preferably 28.0%, more preferably 26.0%, more preferably 24.0%, more preferably 22.0%, more preferably 20.0%, more preferably 18 The upper limit may be 0.0%, more preferably 16.0%, more preferably 14.0%, and still more preferably 13.0%. In addition, since TiO ₂ is an optional component, it is possible to produce the glass of the present invention even if it is not contained, but in order to facilitate the above effect, it preferably exceeds 0%, more preferably The lower limit is 0.3%, more preferably 0.8%, more preferably 1.0%, and still more preferably 1.5%. For example, it is preferably 1.0 to 20.0%, and more preferably 1.5 to 15.0%.
The TiO ₂ component can be contained in the glass using, for example, TiO ₂ as a raw material.

The B ₂ O ₃ component is an optional component that acts as a glass-forming oxide and is effective in lowering the glass transition point (Tg). However, if the amount is too large, chemical durability tends to deteriorate. Therefore, it is preferable to contain more than 0%, more preferably 0.4%, more preferably 0.6%, more preferably 0.8%, and still more preferably 1.0% as the lower limit. Is 30.0%, more preferably 20.0%, more preferably 15.0%, more preferably 13.0%, more preferably 12.0%, more preferably 11.0%, still more preferably 10%. .4% as an upper limit. For example, it is preferably more than 0% and 12.0% or less, more preferably more than 0% and 10.4% or less.
B ₂ O ₃ can be contained in the glass using, for example, H ₃ BO ₃ or B ₂ O ₃ as a raw material.

The SiO ₂ component is an optional component that acts as a glass-forming oxide, and is effective in increasing the viscosity of the glass and improving devitrification resistance and chemical durability. However, if the amount is too small, the effect is insufficient. On the other hand, if the amount is too large, the devitrification resistance and the meltability tend to deteriorate. Therefore, it preferably exceeds 0%, preferably 0.1%, more preferably 0.2%, more preferably 0.4%, more preferably 0.6%, and even more preferably 0.8%. Preferably 30.0%, more preferably 20.0%, more preferably 10.0%, more preferably 5.0%, more preferably 3.0%, and more preferably 2.0.0%. 0%, more preferably 1.5% can be contained as an upper limit. For example, it is preferably 0 to 30.0%.
The SiO ₂ component can be contained in the glass using, for example, SiO ₂ as a raw material.

The GeO ₂ component is an optional component having an effect of increasing the refractive index and improving the devitrification resistance, and acts as a glass forming oxide. However, if the amount is too large, the raw material is very expensive, which increases the cost. Therefore, the upper limit is preferably 20.0%, more preferably 10.0%, more preferably 5.0%, and still more preferably 3.0%.
The GeO ₂ component can be contained in the glass using, for example, GeO ₂ as a raw material.

The TeO ₂ component is a component that has an effect of increasing the refractive index. When melting a glass raw material in a platinum crucible or a melting tank in which a portion in contact with molten glass is formed of platinum, tellurium and platinum are alloyed. Since the heat resistance is likely to deteriorate in the alloyed part, there is a concern about the risk of an accident that a hole is opened in the part and the molten glass flows out. Accordingly, the upper limit is preferably 20.0%, more preferably 10.0%, more preferably 5.0%, and still more preferably 3.0%.
The TeO ₂ component can be contained in the glass using, for example, TeO ₂ as a raw material.

The Li ₂ O component has the effect of reducing the partial dispersion ratio, significantly lowering the glass transition temperature (Tg), and promoting the melting of the mixed glass raw material. In the composition system of the present invention, the reheat press molding is effective. There is an effect to suppress devitrification. However, if the amount is too large, the devitrification resistance tends to deteriorate rapidly. Accordingly, the upper limit is preferably 30.0%, more preferably 25.0%, more preferably 20.0%, more preferably 15.0%, more preferably 10.0%, and even more preferably 7.0%. It can contain as. In addition, since Li ₂ O is an optional component, it is possible to produce the glass of the present invention even if it is not contained. However, in order to facilitate the above effect, it preferably exceeds 0%, more preferably May be contained at a lower limit of 1.0%, more preferably 2.0%, and still more preferably 2.5%.
The Li ₂ O component can be contained in the glass using, for example, Li ₂ O or a carbonate, nitrate, hydroxide, or the like as a raw material.

The Na ₂ O component has the effect of lowering the glass transition temperature (Tg) and promoting the melting of the mixed glass raw material. However, if the amount is too large, the devitrification resistance tends to deteriorate rapidly. Therefore, preferably 40.0%, more preferably 39.5%, more preferably 39.0%, more preferably 38.5%, more preferably 38.0%, more preferably 37.0%, Preferably it can contain 36.0% as an upper limit. In addition, since Na ₂ O is an optional component, it is possible to produce the glass of the present invention even if it is not contained. However, in order to easily exhibit the effect, it preferably exceeds 0%, more preferably Is 5.0%, more preferably 10.0%, more preferably 15.0%, more preferably 17.0%, and still more preferably 18.0%.
The Na ₂ O component can be contained in the glass by using, for example, Na ₂ O or its carbonate, nitrate, hydroxide, etc. as a raw material.

The optical glass of the present invention, the content of Nb ₂ O ₅ component to (mol%) Na ₂ O content of component ratio _{(mol%) (Na 2 O / Nb} 2 O 5) is 0.3 or more It is preferable that it is 2.0 or less. In particular, by setting this ratio to 2.0 or less, the number of components that increase the refractive index increases, so that a desired low partial dispersion ratio can be easily obtained while obtaining a desired refractive index. Therefore, the above molar ratio (Na ₂ O / Nb ₂ O ₅ ) in the oxide conversion composition is preferably 2.0, more preferably 1.8, and most preferably 1.5. On the other hand, by making these ratios 0.3 or more, the devitrification resistance of the glass can be increased (for example, the liquidus temperature can be lowered). Accordingly, the lower limit is preferably 0.3, more preferably 0.5, and most preferably 0.6.

The optical glass of the present invention preferably contains one or more selected from the group consisting of a P ₂ O ₅ component, a B ₂ O ₃ component, and a Na ₂ O component. Thereby, since the component which reduces the partial dispersion ratio ((theta) g, F) of glass is contained, it can be made easy to obtain a desired low partial dispersion ratio. In particular, this effect becomes remarkable when the sum of these contents is 30.0% or more. Therefore, the sum (P ₂ O ₅ + B ₂ O ₃ + Na ₂ O) of the content of the oxide conversion composition with respect to the total amount of glass is preferably 30.0%, more preferably 43.0%, and even more preferably 45. 0.0%, most preferably 50.0% is the lower limit. On the other hand, by making the sum of these contents 80.0% or less, the stability of the glass can be improved and the devitrification resistance of the glass can be improved. Therefore, the sum (P ₂ O ₅ + B ₂ O ₃ + Na ₂ O) of the content with respect to the total amount of glass in the oxide conversion composition is preferably 80.0%, more preferably 75.0%, and even more preferably 70. 0.0%, and most preferably 70.0%.

The K ₂ O component has the effect of lowering the glass transition temperature (Tg) and promoting the melting of the mixed glass raw material. However, when the amount is too large, the devitrification resistance deteriorates rapidly, and in the composition system of the present invention, the devitrification property at the time of reheat press molding tends to deteriorate rapidly. Therefore, the upper limit is preferably 25.0%, more preferably 15.0%, more preferably 10.0%, more preferably 7.0%, more preferably 6.5%, and even more preferably 3.5%. It can contain as.
The K ₂ O component can be contained in the glass using, for example, K ₂ O or a carbonate, nitrate, hydroxide, or the like as a raw material.

In the optical glass of the present invention, the ratio (Li ₂ O / (Na ₂ O + K ₂ O)) of the Li ₂ O component to the sum of the contents (mol%) of the Na ₂ O component and the K ₂ O component is 1.0 or less. In particular, by setting these ratios to 1.0 or less, a component that lowers the partial dispersion ratio (θg, F) of the glass is included, so that a desired low partial dispersion ratio can be easily obtained. Therefore, the molar ratio (Li ₂ O / (Na ₂ O + K ₂ O)) in the oxide equivalent composition is preferably 1.0 or less, more preferably 0.7 or less, and even more preferably 0.5 or less, most preferably Preferably it is 0.2 or less.

The Cs ₂ O component has an effect of lowering the glass transition temperature (Tg) and promoting the melting of the mixed glass raw material. Accordingly, the upper limit is preferably 20.0%, more preferably 15.0%, more preferably 10.0%, more preferably 7.0%, more preferably 6.5%, and even more preferably 3.5%. It can contain as.
Cs ₂ O component, the raw material as for example Cs ₂ O or a carbonate, nitrate, hydroxide and the like can be contained in the glass by using.

The MgO component is effective for adjusting the optical constant. However, if the amount is too large, the devitrification resistance tends to deteriorate. Accordingly, the upper limit of the amount of this component is preferably 15.0%, more preferably 10.0%, more preferably 7.0%, more preferably 6.5%, and still more preferably 3.5%.
The MgO component can be contained in the glass using, for example, MgO or a carbonate, nitrate, hydroxide, or the like as a raw material.

The CaO component is effective for adjusting the optical constant. However, if the amount is too large, the devitrification resistance tends to deteriorate. Therefore, it is preferably 20.0%, more preferably 15.0%, more preferably 10.0%, more preferably 8.0%, more preferably 7.0%, more preferably 6.5%, Preferably it can contain 6.0% as an upper limit.
The CaO component can be contained in the glass using, for example, CaO or a carbonate, nitrate, hydroxide, or the like as a raw material.

The SrO component is effective for adjusting the optical constant. However, if the amount is too large, the devitrification resistance tends to deteriorate. Accordingly, the upper limit is preferably 20.0%, more preferably 15.0%, more preferably 10.0%, more preferably 7.0%, more preferably 6.5%, and even more preferably 3.5%. It can contain as.
The SrO component can be contained in the glass using, for example, SrO or a carbonate, nitrate, hydroxide, or the like as a raw material.

The BaO component is effective for adjusting the optical constant. However, if the amount is too large, the devitrification resistance tends to deteriorate. Therefore, preferably 30.0%, more preferably 20.0%, more preferably 15.0%, more preferably 14.5%, more preferably 14.0%, more preferably 13.5%, Preferably it can contain 12.5% as an upper limit.
The BaO component can be contained in the glass using, for example, BaO or a carbonate, nitrate, hydroxide, or the like as a raw material.

The optical glass of the present invention preferably contains one or more selected from the group consisting of MgO component, CaO component, SrO component and BaO component. Thereby, since the component which reduces the partial dispersion ratio ((theta) g, F) of glass is contained, it can be made easy to obtain a desired low partial dispersion ratio. In particular, this effect becomes significant when the sum of these contents exceeds 0. Therefore, the sum (MgO + CaO + SrO + BaO) of the content of the oxide conversion composition with respect to the total amount of glass is preferably more than 0, more preferably 0.1%, still more preferably 1.0%, and most preferably 3.0%. Is the lower limit. On the other hand, by making the sum of these contents 30.0% or less, the stability of the glass can be improved and the devitrification resistance of the glass can be improved.
Therefore, the sum (MgO + CaO + SrO + BaO) of the content of the oxide conversion composition with respect to the total amount of glass is preferably 30.0%, more preferably 25.0%, and most preferably 20.0%.

The ZnO component has the effect of lowering the glass transition temperature (Tg) and improving chemical durability. However, if the amount is too large, the devitrification resistance tends to deteriorate. Therefore, preferably 30.0%, more preferably 20.0%, more preferably 15.0%, more preferably 10.0%, more preferably 7.0%, more preferably 6.5%, Preferably it can contain 3.5% as an upper limit.
The ZnO component can be contained in the glass using, for example, ZnO as a raw material.

The Al ₂ O ₃ component is an optional component effective for improving chemical durability. However, if the amount is too large, the devitrification resistance tends to deteriorate. Accordingly, the upper limit is preferably 20.0%, more preferably 10.0%, more preferably 5.0%, more preferably 4.0%, and still more preferably 3.5%.
The Al ₂ O ₃ component can be contained in the glass using, for example, Al ₂ O ₃ or Al (OH) ₃ as a raw material.

The ZrO ₂ component has the effect of increasing the refractive index, reducing the partial dispersion ratio, and improving the chemical durability. However, if the amount is too large, the devitrification resistance tends to deteriorate. Accordingly, the upper limit is preferably 20.0%, more preferably 15.0%, and still more preferably 10.0%. In addition, since ZrO ₂ is an optional component, it is possible to produce the glass of the present invention even if it is not contained. However, in order to facilitate the above effect, it preferably exceeds 0%, more preferably The lower limit is 0.1%, more preferably 1.0%.
The ZrO ₂ component can be contained in the glass using, for example, ZrO ₂ as a raw material.

The WO ₃ component has the effect of adjusting the optical constant, improving devitrification resistance, and increasing the partial dispersion ratio. However, if the amount is too large, the devitrification resistance and the light transmittance in the short wavelength region of the visible light region are adversely affected. Accordingly, the upper limit is preferably 20.0%, preferably 15.0%, more preferably 10.0%, more preferably 6.0%, more preferably 4.0%, and even more preferably 3.5%. Can be contained. For example, the content is preferably more than 0% and not more than 8.0%, and more preferably 2.0 to 5.0%.
The WO ₃ component can be contained in the glass using, for example, WO ₃ as a raw material.

The Bi ₂ O ₃ component has the effect of increasing the refractive index, increasing the dispersion, reducing the partial dispersion ratio, and lowering the glass transition temperature (Tg). However, if the amount is too large, the devitrification resistance tends to deteriorate, and the partial dispersion ratio tends to increase. Accordingly, it preferably exceeds 0%, preferably 0.1%, more preferably 0.2%, more preferably 0.3%, more preferably 0.35%, more preferably 0.4%, and even more preferably. May contain 0.5% as the lower limit, preferably 20.0%, more preferably 10.0%, more preferably 7.0%, and even more preferably 4.0% as the upper limit. Can do. For example, 0 to 10.0% is preferable, 0 to 6.0% is more preferable, and 0 to 4.0% is more preferable.
The Bi ₂ O ₃ component can be contained in the glass using, for example, Bi ₂ O ₃ as a raw material.

The La ₂ O ₃ component is an effective component for increasing the refractive index of the glass and reducing the dispersion. However, if the amount is too large, the devitrification resistance tends to deteriorate. Therefore, the upper limit is preferably 20.0%, more preferably 10.0%, more preferably 5.0%, and still more preferably 3.0%.
The La ₂ O ₃ component can be contained in the glass using, for example, La ₂ O ₃ , lanthanum nitrate or a hydrate thereof as a raw material.

The Gd ₂ O ₃ component is effective for increasing the refractive index of the glass and lowering the dispersion. However, if the amount is too large, the devitrification resistance tends to deteriorate. Accordingly, the content is preferably 20.0%, more preferably 10.0%, more preferably 5.0%, more preferably 3.0%, more preferably 2.0%, and even more preferably 1.5%. can do.
Gd ₂ O ₃ can be contained in the glass using, for example, Gd ₂ O ₃ as a raw material.

The Y ₂ O ₃ component is effective in increasing the refractive index of the glass and lowering the dispersion. However, if the amount is too large, the devitrification resistance tends to deteriorate. Therefore, the upper limit is preferably 20.0%, more preferably 10.0%, more preferably 5.0%, and still more preferably 3.0%.
The Y ₂ O ₃ component can be contained in the glass using, for example, Y ₂ O ₃ as a raw material.

The Ta ₂ O ₅ component has an effect of increasing the refractive index and improving chemical durability and devitrification resistance. However, if the amount is too large, the devitrification resistance tends to deteriorate. Therefore, preferably 20.0%, preferably 15.0%, more preferably 10.0%, more preferably 8.0%, preferably 6.0%, more preferably 5.0%, more preferably It can contain 4.0%, more preferably 3.5% as an upper limit.
The Ta ₂ O ₅ component can be contained in the glass using, for example, Ta ₂ O ₅ as a raw material.

The In ₂ O ₃ component is effective in increasing the refractive index of the glass and lowering the dispersion. Accordingly, the upper limit is preferably 20.0%, more preferably 15.0%, more preferably 10.0%, more preferably 7.0%, more preferably 6.5%, and even more preferably 3.5%. It can contain as.
The In ₂ O ₃ component can be contained in the glass using, for example, In ₂ O ₃ or In ₂ F ₃ as a raw material.

The Yb ₂ O ₃ component is effective in increasing the refractive index of the glass and lowering the dispersion. However, if the amount is too large, devitrification resistance and chemical durability are likely to deteriorate. Therefore, the upper limit is preferably 20.0%, preferably 10.0%, more preferably 5.0%, and still more preferably 3.0%.
The Yb ₂ O ₃ component can be contained in the glass using, for example, Yb ₂ O ₃ as a raw material.

The Ga ₂ O ₃ component is a component having an effect of increasing the refractive index, but the raw material is very expensive. Accordingly, the upper limit is preferably 10.0%, more preferably 5.0%, and still more preferably 3.0%.
The Ga ₂ O ₃ component can be contained in the glass using, for example, Ga ₂ O ₃ as a raw material.

The Sb ₂ O ₃ component can be optionally added for defoaming when the glass is melted, but if the amount is too large, the transmittance in the short wavelength region of the visible light region tends to deteriorate. Therefore, it is preferable to contain more than 0%, more preferably 0.05%, more preferably 0.10%, and still more preferably 0.14%, preferably 1.0%, more preferably May be contained at an upper limit of 0.50%, more preferably 0.30%, and still more preferably 0.20%. For example, it is preferably more than 0 and 1.0% or less, more preferably more than 0 and 0.5% or less.
Note that the content (%) of the Sb ₂ O ₃ component means an externally added amount (mol%). Here, the “outside split” represents the mol% of Sb ₂ O ₃ alone in terms of oxide, when the molar amount of the whole glass composition component excluding the Sb ₂ O ₃ component is 100.

The CeO ₂ component is a component having an effect of improving devitrification resistance. However, if the amount is too large, the light transmittance in the short wavelength region is likely to deteriorate. Therefore, it may contain more than 0%, preferably 0.05%, more preferably 0.10%, and still more preferably 0.14%, preferably 1.0%, more preferably 0.1%. The upper limit may be 50%, more preferably 0.30%, and still more preferably 0.20%.
The CeO ₂ component can be contained in the glass using, for example, CeO ₂ as a raw material.

  In addition, the raw material used in order to contain each component which exists in the said glass was described for the purpose of illustration, and is not limited to the said enumerated oxide etc. That is, it can be selected from known raw materials in accordance with various changes in the glass production conditions.

Lu ₂ O _3, but the components of SnO _2, BeO is possible to contain, Lu ₂ O ₃ in an actual manufacturing becomes high raw material cost because it is expensive raw materials impractical, SnO ₂ is When a glass raw material is melted in a platinum crucible or in a melting tank where the molten glass is made of platinum, the portion where tin and platinum are alloyed to become an alloy has poor heat resistance. There is concern about the danger of accidents in which holes are opened and molten glass flows out, and there is a problem that BeO is a component that has a harmful effect on the environment and a very large environmental load. Accordingly, it is preferably contained in an amount of less than 0.1%, more preferably 0.05%, and even more preferably not contained.

  Next, components that should not be contained in the optical glass of the present invention will be described.

  Since lead compounds are a component that has a large environmental impact, not only for glass production, but also for cold processing of glass such as polishing and disposal of glass. It should not be included in the optical glass of the invention.

Since As ₂ O ₃ , cadmium and thorium are harmful components to the environment and are very environmentally harmful components, they should not be contained in the optical glass of the present invention.

  Furthermore, it is preferable that the optical glass of the present invention does not contain coloring components such as V, Cr, Mn, Fe, Co, Ni, Cu, Mo, Eu, Nd, Sm, Tb, Dy, and Er. However, the term “not contained” means that it is not contained artificially unless it is mixed as an impurity.

  In addition, the notation on the basis of oxides of the content of each component used in this specification is that all oxides, composite salts, metal fluorides, etc. used as raw materials for the glass constituents of the present invention are melted. When it assumes that it decomposes | disassembles and changes to an oxide, it represents the mol% of the said production | generation oxide of each component with respect to the whole composition.

Next, the physical properties of the optical glass of the present invention will be described.
As described above, in the optical glass of the present invention, the partial dispersion ratio (θg, F) is within the range of ν _d ≦ 25 with respect to the Abbe number (ν _d ), and the formula (1): [(−0.0016 × (ν _d +0.63460) ≦ (θg, F) ≦ (−0.00563 × ν _d +0.75873)].
In such a range of ν _d ≦ 25, it is preferable to satisfy the relationship (−0.0016 × ν _d +0.63660) ≦ (θg, F), and (−0.0016 × ν _d +0.63860) ≦ ( It is more preferable to satisfy the relationship of θg, F).
Further, in such a range of ν _d ≦ 25, it is preferable to satisfy the relationship of (θg, F) ≦ (−0.00563 × ν _d +0.755633), and (θg, F) ≦ (−0.00563 ×). (ν _d +0.75463) is more preferable, and (θg, F) ≦ (−0.00562 × ν _d +0.75263) is more preferable.
Further, in the optical glass of the present invention, the partial dispersion ratio (θg, F) is in the range of ν _d > 25 between the Abbe number (ν _d ) and the formula (2): [(−0.0025 × ν _d +0.65710) ≦ (θg, F) ≦ (−0.0034 × ν _d +0.70300)].
In such a range of ν _d > 25, it is preferable to satisfy the relationship (−0.0025 × ν _d +0.65910) ≦ (θg, F), and (−0.0025 × ν _d +0.66110) ≦ ( It is more preferable to satisfy the relationship of θg, F).
In such a range of ν _d > 25, it is preferable to satisfy the relationship of (θg, F) ≦ (−0.00340 × ν _d +0.70100), and (θg, F) ≦ (−0.00340 × (ν _d +0.69900) is more preferable, and (θg, F) ≦ (−0.00340 × ν _d +0.69700) is more preferable.
The optical glass of the present invention satisfies such a relationship. That is, it is an optical glass having a high refractive index and high dispersibility and a small partial dispersion ratio.

  In the present invention, the partial dispersion ratio (θg, F) is the refractive index (nC), F in the C-line (wavelength: 656.27 nm) for the optical glass obtained at a slow cooling rate of -25 ° C / hour. The refractive index (nF) at the line (wavelength: 486.13 nm) and the refractive index (ng) at the g line (wavelength: 435.835 nm) are measured, and (θg, F) = (ng−nF) / (nF−nC). ) Means the value calculated by the formula.

The optical glass of the present invention further has good transmittance. Specifically, the wavelength (λ ₈₀ ) at which the transmittance is 80% is preferably 530 nm or less, more preferably 510 nm or less, more preferably 490 nm or less, more preferably 470 nm or less, and even more preferably 460 nm or less. The wavelength (λ ₇₀ ) at which the transmittance is 70% is preferably 450 nm or less, more preferably 440 nm or less, more preferably 430 nm or less, and further preferably 425 nm or less. The wavelength (λ ₅ ) at which the transmittance is 5% is preferably 400 nm or less, more preferably 375 nm or less, more preferably 370 nm or less, and further preferably 365 nm or less.
Incidentally, the transmittance is relative to the incident light intensity when irradiated perpendicularly to one of the optically polished surfaces of a glass sample subjected to parallel and flat optical polishing having a thickness of 10.0 ± 0.1 mm. It is represented by the ratio of the intensity of transmitted light transmitted through the glass sample and emitted from the other optical polishing surface (transmitted light intensity / incident light intensity). The wavelength at which the transmittance is 80% is λ ₈₀ , the wavelength at 70% is λ ₇₀ , and the wavelength at 5% is λ ₅ .

The optical glass of the present invention has a refractive index (n _d ) of 1.70 or more and 2.00 or less, an Abbe number (ν _d ) of 15 or more and 35 or less, and a spectral transmittance of 70%. The wavelength (λ ₇₀ ) shown is preferably 500 nm or less.
Here, the refractive index (n _d ) is more preferably 1.72 or more, more preferably 1.74 or more, more preferably 1.76 or more, more preferably 1.77 or more, and even more preferably 1.78 or more. . The refractive index (n _d) is more preferably 1.96 or less, more preferably 1.92 or less, more preferably 1.88 or less, more preferably 1.86 or less, more preferably 1.85 or less, 1 .84 or less is more preferable.
Further, the Abbe number (ν _d ) is more preferably 17 or more, more preferably 19 or more, preferably 20 or more, more preferably 21 or more, and further preferably 22 or more. Further, the Abbe number (ν _d ) is more preferably 33 or less, more preferably 30 or less, more preferably 28 or less, more preferably 27 or less, and even more preferably 26 or less.
The wavelength (λ ₇₀ ) is more preferably 480 nm or less, more preferably 460 nm or less, more preferably 440 nm or less, more preferably 430 nm or less, and 420 nm or less. More preferably, it is 410 nm or less.

  As described above, the optical glass of the present invention is an optical glass having a high refractive index and a high dispersibility, a small partial dispersion ratio, and a good transmittance.

In the optical glass of the present invention, when the glass transition point (Tg) becomes too high, as described above, when precision press molding is performed, deterioration of the mold tends to occur. Therefore, Tg of the optical glass of the present invention is preferably 650 ° C., more preferably 620 ° C., and further preferably 600 ° C.
The yield point (At) is preferably 700 ° C., more preferably 670 ° C., and further preferably 650 ° C. or less.

  The optical glass of the present invention is useful for various optical elements and optical designs. For example, the optical glass of the present invention can be ground and polished to obtain an optical glass. Further, for example, an optical glass for precision press molding can be obtained from the optical glass of the present invention. Among them, it is particularly preferable to form a preform from the optical glass of the present invention, and to produce optical elements such as lenses, prisms, mirrors and the like by using means such as polishing and precision press molding for the preform. . As a result, when used in optical devices that transmit visible light to optical elements such as cameras and projectors, the optical system in these optical devices can be miniaturized while realizing high-definition and high-precision imaging characteristics. Can be planned. Here, the method for producing the preform material is not particularly limited. For example, a glass gob forming method described in JP-A-8-319124 and an optical glass manufacturing method and manufacturing apparatus described in JP-A-8-73229 are disclosed. Thus, a method of manufacturing a preform material directly from molten glass can also be used, and a method of manufacturing by performing cold processing such as grinding and polishing on a strip material formed from optical glass can also be used.

In addition, when manufacturing a preform by dripping molten glass using the optical glass of the present invention, if the viscosity of the molten glass is too low, the glass preform tends to have striae. It becomes difficult to cut glass by tension.
Therefore, for high quality and stable production, the logarithmic log η value of the viscosity (dPa · s) at the liquidus temperature is preferably 0.3 to 2.0, more preferably 0.4 to 1.8, More preferably, it is the range of 0.5-1.6.

  Examples of the present invention and comparative examples will be described below, but the present invention is not limited to these examples.

The compositions of Examples 1 to 41 and Comparative Examples 1 to 3 of the glass of the present invention are expressed by the refractive index (n _d ), Abbe number (ν _d ), partial dispersion ratio (θg, F), λ ₈₀ , λ ₇₀ , λ ₅ , refractive index (nC) at C line (wavelength: 656.27 nm), refractive index (nF) at F line (wavelength: 486.13 nm), refractive index at g line (wavelength: 435.835 nm) It is shown in Table 1 together with (ng). In the table, the composition of each component is expressed in mol%. Further, the content (%) of the Sb ₂ O ₃ component means an externally added amount (mol%).

  The optical glasses of Examples of the present invention shown in Table 1 (Examples 1 to 41 and Comparative Examples 1 to 3) are the first optical glass materials such as oxides, hydroxides, carbonates and nitrates. Weighing, mixing, and pouring into a platinum crucible at the composition ratio of each example shown in the table, melting, clarifying and stirring at 950 to 1400 ° C. for 3 to 5 hours depending on the meltability depending on the composition Then, after homogenizing, it was obtained by casting into a mold or the like and gradually cooling.

The refractive index (n _d ) and the Abbe number (ν _d ) were measured for the optical glass obtained at a slow cooling rate of −25 ° C./hour.

  The partial dispersion ratio (θg, F) is the refractive index (nC) in the C line (wavelength: 656.27 nm) and the F line (wavelength: 486) for the optical glass obtained at a slow cooling rate of −25 ° C./hour. .13 nm) and the refractive index (ng) at the g line (wavelength: 435.835 nm) were measured and calculated by the equation of θg, F = (ng−nF) / (nF−nC). .

Further, λ ₈₀ , λ ₇₀ , and λ ₅ were measured using “U-4100” manufactured by Hitachi, Ltd.

As can be seen from Table 1, the Abbe number (ν _d ) and the partial dispersion ratio (θg, F) in the optical glass (Examples 1 to 41) of the examples of the present invention are expressed by Equations (1) and (2). ). Also, the refractive index (n _d ) is 1.77 or higher and is high. Further, λ ₈₀ is 524.5 nm or less, λ ₇₀ is 447.5 nm or less, and λ ₅ is 390 nm or less. That is, the transmittance is also good. Therefore, it can be said that the optical glass of Examples 1-41 has a high refractive index and a high dispersibility, a small partial dispersion ratio, and a good transmittance.

  Furthermore, using the optical glass of the example of the present invention, after forming a preform for polishing, grinding and polishing were performed to form lenses and prisms. In addition, a precision press-molding preform was formed using the optical glass of the example of the present invention, and the precision press-molding preform was precision press-molded into a lens and a prism. In either case, it could be processed into various lens and prism shapes.

Claims (8)

The glass the total amount of substance of the oxide composition in terms of, in mole _percent, from 10.0 to 60.0% of P 2 _{O 5} component, 10.0 to 45.0% of _Nb 2 _{O 5} component, TiO ₂ component 0 to 30.0%,
Between the partial dispersion ratio (θg, F) and the Abbe number (ν _d ),
In the range of ν _d ≦ 25, the relationship of (−0.0016 × ν _d +0.63460) ≦ (θg, F) ≦ (−0.00563 × ν _d +0.75873) is satisfied,
Optical glass satisfying the relationship of (−0.0025 × ν _d +0.65710) ≦ (θg, F) ≦ (−0.0034 × ν _d +0.70300) in the range of ν _d > 25. The optical glass according to claim 1, comprising B ₂ O ₃ . B contains ₂ O ₃ component less 0% and 10.4%, the optical glass according to claim 1 or 2. The glass the total amount of substance of the oxide composition in terms of, SiO ₂ component from 0 to 30.0% by mole%
GeO ₂ component 0 to 20.0%
TeO ₂ component 0 to 20.0%
Li ₂ O component 0 to 30.0%
Na ₂ O component 0-40.0%
K ₂ O component 0 to 25.0%
Cs ₂ O component 0 to 20.0%
MgO component 0 to 15.0%
CaO component 0 to 20.0%
SrO component 0 to 20.0%
BaO component 0 to 30.0%
ZnO component 0 to 30.0%
Al ₂ O ₃ component 0 to 20.0%
ZrO ₂ component 0 to 20.0%
WO ₃ component 0 to 20.0%
Bi ₂ O ₃ component 0 to 20.0%
La ₂ O ₃ component 0 to 20.0%
Gd ₂ O ₃ component 0 to 20.0%
Y ₂ O ₃ component 0 to 20.0%
Ta ₂ O ₅ component 0 to 20.0%
In ₂ O ₃ component 0 to 20.0%
Yb ₂ O ₃ component 0 to 20.0%
CeO ₂ component 0-1.0%
Sb ₂ O ₃ component 0 to 1.0% in an externally added amount (mol%) with respect to the total amount of glass of oxide conversion composition
The optical glass according to claim 1, further comprising: A wavelength (λ ₇₀ ) having a refractive index (n _d ) of 1.70 or more and 2.00 or less, an Abbe number (ν _d ) of 15 or more and 35 or less, and a spectral transmittance of 70% is 500 nm or less. The optical glass according to claim 1.   An optical element made by grinding and polishing the optical glass according to claim 1.   An optical element formed by precision press-molding the optical glass according to claim 1. A precision press-molding preform comprising the optical glass according to claim 1.