JP2014009112A - Optical glass and usage thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical glass that exhibits excellent melting property, while being a high refractive glass.SOLUTION: An optical glass is an oxide glass including: as a cationic component, Pof 10-40% by cation; Ti, Nb, W, Biand Teof equal to or more than 50% by cation, in total (where a cation ratio of the total content of Tiand Nbwith regard to the total content of Wand Bi((Ti+Nb)/(W+Bi)) is 1.3 or lower); B, Li, Na, K, Rb, Cs, Mg, Ca, Sr, Baand Znof, in total, equal to or less than one third of the total content of Ti, Nb, W, Biand Te; and more than 0% of Li, Na, K, Rband Csin total. The refractive index of the optical glass is 2.02 or higher.

Description

  The present invention relates to an optical glass having a high refractive index and a method for producing the same, a glass material for press molding made of the optical glass and an optical element, and a method for producing the optical element.

  An optical element made of optical glass having a high refractive index, such as the optical glass described in Patent Document 1, is effective for increasing the functionality and compactness of the imaging optical system and the projection optical system.

JP 2012-91989

  In a general optical glass manufacturing process, a compound raw material (batch raw material) is roughly melted using a refractory melting vessel such as a quartz crucible to produce a cullet raw material, and then the cullet raw material is made of platinum or gold. An optical glass is obtained by melting, clarifying and homogenizing using a precious metal melting vessel and molding the resulting molten glass. The clarification performed after melting is a process performed to remove bubbles in the molten glass, and raises the temperature of the molten glass to reduce the viscosity, thereby promoting the blowout of bubbles in the glass.

  Increasing the content of the high refractive index component in order to increase the refractive index of the glass, such as phosphoric acid component, boric acid component, alkali metal component, divalent metal component, etc. that have a function to improve the meltability of the glass The content is relatively lowered. As a result, the meltability of the glass tends to deteriorate. Therefore, in the conventional high refractive index glass, measures such as increasing the melting temperature and extending the melting time have been taken in order to completely melt the glass raw material.

As described above, in the clarification, the temperature of the molten glass is raised, so the clarification temperature is higher than the melting temperature. Therefore, when the melting temperature is increased, the fining temperature is increased accordingly. In the conventional high refractive index glass, the refining temperature is usually over 1100 ° C., and it is not uncommon to exceed 1400 ° C. in order to make the glass suitable for blowing bubbles. However, when the temperature of the glass is increased in the melting and refining processes, high refractive index components such as Ti ⁴⁺ , Nb ⁵⁺ , W ⁶⁺ , Bi ³⁺ , Te ⁴⁺ are reduced, and the color of the glass (so-called reduced color) increases. Or a metal material such as platinum or gold constituting the glass melting container melts into the glass as ions, causing a phenomenon in which the glass is colored or foreign substances in the glass are increased.

  Under such circumstances, an object of the present invention is to provide an optical glass exhibiting excellent meltability while being a high refractive index glass.

In a general manufacturing process of optical glass, a cullet raw material is melted to be melted, and then the temperature of the melt is raised to clarify, and after the temperature of the melt is lowered after clarification, the glass is flowed out and molded. The rough melting in the production of the cullet raw material is carried out using a refractory melting apparatus such as quartz because it shows severe erosion in the process of melting the batch raw material. However, in the process of melting, clarifying, and homogenizing the cullet raw material, if a refractory container is used, the refractory melts into the glass, making it difficult to obtain a homogeneous molten glass, and the optical properties such as the refractive index also vary. Therefore, it is preferable to use a container made of a noble metal such as platinum or gold. Thus, among the series of steps performed using the noble metal container, the temperature of the glass melt is highest during clarification. The clarification is preferably performed at a temperature at which the viscosity of the molten glass is about 1.0 dPa · s so that bubbles of the glass melt rise and are easily discharged from the melt. A high refractive index glass, for example, a glass having a refractive index nd of more than 2.0 generally has a high melting temperature and a fining temperature, and it is not uncommon for the fining temperature to exceed 1400 ° C. However, when melting and clarification are performed at a high temperature, the glass is colored as described above, or foreign substances in the glass are increased.
On the other hand, as a result of intensive studies, the present inventor has been based on an oxide glass composition containing P ⁵⁺ , and has a high refractive index component Ti ⁴⁺ , Nb ⁵⁺ , W ⁶⁺ , Bi ³⁺ , Te ⁴⁺ , and glass meltability. By containing the components B ³⁺ , Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ , Mg ²⁺ , Ca ²⁺ , Sr ²⁺ , Ba ²⁺ and Zn ²⁺ in a required distribution by improving the refractive index While the ratio nd is in the range exceeding 2.0, specifically 2.02 or more, viscosity characteristics can be imparted such that the clarification temperature is, for example, 1100 ° C. or less, thereby increasing the melting temperature and the clarification temperature. The present inventors have found that a high refractive index glass free from defective bubble breakage can be obtained while suppressing the coloring of the glass and the increase in foreign matters resulting from the above.

That is, the above object was achieved by the following means.
[1] As a cation component,
10 to 40 cation% P ⁵⁺
Ti ⁴⁺ , Nb ⁵⁺ , W ⁶⁺ , Bi ³⁺ and Te ⁴⁺ total 50 cation% or more (provided that the cation ratio of the total content of Ti ⁴⁺ and Nb ^{5+ to} the total content of W ⁶⁺ and Bi ³⁺ ((Ti ⁴⁺ + Nb ⁵⁺ ) / (W ⁶⁺ + Bi ³⁺ )) is 1.3 or less)
B ³⁺ , Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ , Mg ²⁺ , Ca ²⁺ , Sr ²⁺ , Ba ²⁺ and Zn ²⁺ in total, Ti ⁴⁺ , Nb ⁵⁺ , W ⁶⁺ , Bi ³⁺ and Te ⁴⁺ 1/3 or less of the total content of
Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ and Cs ⁺ in total exceeding 0%,
An optical glass having a refractive index of 2.02 or more.
[2] The optical glass according to [1], wherein the Abbe number νd is 18.0 or less.
[3] In a method for producing optical glass, comprising melting a glass raw material by heating, clarifying the obtained molten glass, and forming a clarified molten glass,
A method for producing an optical glass, wherein the glass raw material is prepared so that the optical glass according to [1] or [2] is obtained.
[4] The method for producing optical glass according to [3], wherein the melting is performed using a molten glass container prepared using platinum, a platinum alloy, gold, or a gold alloy.
[5] A press-molding glass material comprising the optical glass according to [1] or [2].
[6] An optical element made of the optical glass according to [1] or [2].
[7] By processing the optical glass described in [1] or [2], or by manufacturing the optical glass by the method described in [3] or [4], and processing the manufactured optical glass, An optical element manufacturing method for obtaining an optical element.

According to the present invention, it is possible to achieve both higher refractive index and improved meltability of the optical glass. Therefore, it is possible to provide an optical glass in which the increase in melting temperature is suppressed while the refractive index nd is 2.02 or more. According to the optical glass having excellent meltability, it is possible to obtain a homogeneous glass without excessively increasing the glass melting temperature or excessively increasing the melting time. Coloring of the glass due to the material melting into the molten glass and increase in coloring due to reduction of high refractive index imparting components such as Ti ⁴⁺ , Nb ⁵⁺ , W ⁶⁺ , Bi ³⁺ during melting can be suppressed.
Furthermore, according to the present invention, a glass material for press molding made of the above optical glass, an optical element, for example, an optical element suitable for downsizing and high functionality of an optical system such as an imaging optical system and a projection optical system, and production thereof A method can be provided.

Optical glass In the optical glass of the present invention, P ⁵⁺ is 10 to 40 cation%, Ti ⁴⁺ , Nb ⁵⁺ , W ⁶⁺ , Bi ³⁺ and Te ⁴⁺ as a cation component in total 50 cation% or more (however, W ⁶⁺ and Bi Cation ratio of the total content of Ti ⁴⁺ and Nb ^{5+ to} the total content of ³⁺ ((Ti ⁴⁺ + Nb ⁵⁺ ) / (W ⁶⁺ + Bi ³⁺ )) is 1.3 or less), B ³⁺ , Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ , Mg ²⁺ , Ca ²⁺ , Sr ²⁺ , Ba ²⁺ and Zn ²⁺ in total, not more than 1/3 of the total content of Ti ⁴⁺ , Nb ⁵⁺ , W ⁶⁺ , Bi ³⁺ and Te ⁴⁺ , It is an oxide glass containing a total of more than 0% of Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ and Cs ⁺ , and an optical glass having a refractive index of 2.02 or more.
The optical glass of the present invention can exhibit excellent glass meltability while being a glass having a refractive index nd of 2.02 or higher and an extremely high refractive index. Therefore, it is not necessary to increase the melting temperature excessively, corrosion of glass melting container materials such as platinum and gold can be reduced, and coloring of glass due to the penetration of these metal materials can be reduced. Further, since the foaming is good without excessively increasing the fining temperature, it is possible to obtain optical glass with high homogeneity.

[Glass composition]
Hereinafter, the glass composition of the optical glass of the present invention will be described in detail.
The optical glass of the present invention is an oxide glass, and O ²⁻ is a main component of an anion. The content of O ^2- may be considered as a guideline 90-100 anionic%. If the content of O ²⁻ is within the above range, the other anion components are F ⁻ , Cl ⁻ , Br ⁻ , I ⁻ , S ²⁻ , Se ²⁻ , N ³⁻ , NO ₃ ⁻ , or SO _4. ^2- etc. may be contained. In that case, the total content of F ⁻ , Cl ⁻ , Br ⁻ , I ⁻ , S ²⁻ , Se ²⁻ , N ³⁻ , NO ₃ ⁻ , and SO ₄ ²⁻ is, for example, 0 to 10 anion%. can do. The content of O ²⁻ may be 100 anion%.

  Next, the cation component will be described. Hereinafter, unless otherwise specified, the cation component content and the total content are expressed as cation%.

P ⁵⁺ is a glass network forming component and is an essential component in the optical glass of the present invention. It is effective in improving the thermal stability of the glass, and lowers the liquidus temperature and functions to suppress an increase in temperature at which the glass exhibits a viscosity suitable for blowing bubbles (preferably the viscosity is about 1.0 dPa · s). It is also an ingredient. When the content of P ⁵⁺ is less than 10%, it is difficult to obtain the above effect, and when the content of P ⁵⁺ exceeds 40%, the refractive index decreases and the tendency of crystallization of glass tends to increase. ^Therefore, the content of P ⁵⁺ is set to 10 to 40%. The preferable lower limit of the content of P ⁵⁺ is 12%, and it is more preferable that the lower limit value becomes larger in the order of 14%, 16%, 18%, 20%, 22%, 24%, and 26%. On the other hand, the preferable upper limit of the content of P ⁵⁺ is 38%, and it is more preferable that the upper limit value becomes smaller in the order of 35%, 33%, 31%, 30%, 29%, and 28%.

Ti ⁴⁺ , Nb ⁵⁺ , W ⁶⁺ , Bi ³⁺ , and Te ⁴⁺ all have a function of increasing the refractive index, and Ti ⁴⁺ , Nb ⁵⁺ , W ⁶⁺ , Bi ³⁺ are used to increase the refractive index nd to 2.02 or more. And the total content of Te ⁴⁺ is 50% or more. From the viewpoint of obtaining a glass having a higher refractive index, the preferable lower limit of the total content of Ti ⁴⁺ , Nb ⁵⁺ , W ⁶⁺ , Bi ³⁺ and Te ⁴⁺ is 55%, and hereinafter, 56%, 57%, 58%, 59 Larger values in the order of% and 60% are more preferable as the lower limit value. When the total content of Ti ⁴⁺ , Nb ⁵⁺ , W ⁶⁺ , Bi ³⁺ and Te ⁴⁺ is excessive, the thermal stability of the glass decreases, so the total content of Ti ⁴⁺ , Nb ⁵⁺ , W ⁶⁺ , Bi ³⁺ and Te ⁴⁺ The upper limit of the amount is preferably 75%. Hereinafter, smaller values in the order of 72%, 70%, 68%, and 66% are more preferable as the upper limit value.

^{Ti 4+, Nb 5+, W 6+} , among ^{Bi 3+,} ingredients beneficial effects on the viscosity of the glass melt to lower the temperature indicating the 1.0dPa · s is ^obtained, W 6+, a ^{Bi 3+.} Therefore, in the present invention, the cation ratio of the total content of Ti ⁴⁺ and Nb ^{5+ to} the total content of W ⁶⁺ and Bi ³⁺ in order to suppress an increase in temperature at which the viscosity of the glass melt shows 1.0 dPa · s. ((Ti ⁴⁺ + Nb ⁵⁺ ) / (W ⁶⁺ + Bi ³⁺ )) is set to 1.3 or less. When the cation ratio ((Ti ⁴⁺ + Nb ⁵⁺ ) / (W ⁶⁺ + Bi ³⁺ )) exceeds 1.3, the temperature range is effective for suppressing increase in coloration during glass melting, for example, clearer than the temperature range of 1100 ° C. or lower. The temperature rises. In order to suppress an increase in the fining temperature and suppress an increase in coloration of the glass, the cation ratio ((Ti ⁴⁺ + Nb ⁵⁺ ) / (W ⁶⁺ + Bi ³⁺ )) is preferably set to a range of 1.2 or less. Hereinafter, smaller values in the order of 1.15, 1.10, 1.05, 1.00, and 0.90 are more preferable as the upper limit value.

As described above, Ti ⁴⁺ , Nb ⁵⁺ , W ⁶⁺ , Bi ³⁺ , and Te ⁴⁺ have different effects on the meltability. However, when it is attempted to vitrify all the components without melting, there is a general tendency that the meltability of the glass is deteriorated such that other components deteriorate the coloring of the glass.
On the other ^{hand, B 3+, Li +, Na} +, K +, Rb +, Cs +, Mg 2+, Ca 2+, Sr 2+, Ba 2+, Zn 2+ has the function of improving the meltability of the glass.
In the present invention, in order to maintain the high refractive index characteristics, the total content of B ³⁺ , Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ , Mg ²⁺ , Ca ²⁺ , Sr ²⁺ , Ba ²⁺ and Zn ²⁺ The upper limit is defined by the ratio to the total content of Ti ⁴⁺ , Nb ⁵⁺ , W ⁶⁺ , Bi ³⁺ and Te ⁴⁺ . That is, the total content of B ³⁺ , Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ , Mg ²⁺ , Ca ²⁺ , Sr ²⁺ , Ba ²⁺ and Zn ²⁺ is ^expressed as Ti ⁴⁺ , Nb ⁵⁺ , W ⁶⁺ , Bi The total content of ³⁺ and Te ⁴⁺ is 1/3 or less. In addition, Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ and Cs ⁺ effective for improving the meltability are contained in total exceeding 0%. By doing so, an optical glass having a refractive index nd of 2.02 or more and excellent meltability can be obtained.
Note that B ³⁺ , Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ , Mg ²⁺ , Ca ²⁺ , Sr ²⁺ , Ba ^{2+ with} respect to the total content of Ti ⁴⁺ , Nb ⁵⁺ , W ⁶⁺ , Bi ³⁺ and Te ^4+. and ^{Zn 2+} total content of the cation ratio of ^{((B 3+ + Li + +} Na + + K + + Rb + + Cs + + Mg 2+ + Ca 2+ + Sr 2+ + Ba 2+ + Zn 2+) / (Ti 4+ + Nb 5+ + W 6+ + Bi 3+ + Te 4+)) The preferred upper limit is 3/10, the more preferred upper limit is 1/4, the more preferred upper limit is 9/40, the preferred lower limit is 1/5, the more preferred lower limit is 1/6, and the more preferred lower limit is 3/20, 4 / 30.

Ti ⁴⁺ is a component having a function of dispersing the glass with a high refractive index and a high dispersion, and is an optional component having a function of maintaining the thermal stability of the glass by coexisting with Bi ³⁺ and Nb ⁵⁺ . Therefore, the content can be 0%. It also functions to increase the chemical durability of the glass and increase the mechanical strength of the glass. When the content of Ti ⁴⁺ exceeds 15%, the thermal stability is lowered, the crystallization tendency is increased, the meltability is deteriorated, and the liquidus temperature is remarkably increased. Further, the absorption edge in the spectral transmittance characteristic has a longer wavelength, and the glass tends to be colored brown. Therefore, the content of Ti ⁴⁺ is preferably 0 to 15%. A more preferable upper limit of the content of Ti ⁴⁺ is 14%, a further preferable upper limit is 13%, a still more preferable upper limit is 12%, a still more preferable upper limit is 11%, and a still more preferable upper limit is 10%. The more preferred lower limit of the Ti ⁴⁺ content is 2%, the more preferred lower limit is 3%, the still more preferred lower limit is 4%, the still more preferred lower limit is 5%, and the still more preferred lower limits are 6%, 7% and 8%. is there.

Nb ⁵⁺ is a component having a function of making the glass have a high refractive index and a high dispersion, and is an optional component having a function of maintaining the thermal stability of the glass by coexisting with Bi ³⁺ and Ti ⁴⁺ . It also functions to increase the chemical durability of the glass and increase the mechanical strength of the glass. In order to obtain a desired high refractive index and high dispersion characteristic while maintaining thermal stability, the Nb ⁵⁺ content is preferably 10% or more, more preferably 12% or more, and 13% More preferably, it is 14% or more and 15% or more. On the other hand, when there is too much content of ^{Nb5 +} , the thermal stability of glass will fall, liquid phase temperature will rise remarkably, and the absorption edge in a spectral transmittance characteristic will show the tendency to become a little longer wavelength. Therefore, the Nb ⁵⁺ content is preferably 24% or less. Hereinafter, smaller values in the order of 23%, 22%, 21%, 20%, and 19% are more preferable as the upper limit value.

W ⁶⁺ is an optional component that functions to increase the refractive index and dispersion of the glass and increase the chemical durability and mechanical strength of the glass. Therefore, the content can be 0%. When the content of W ⁶⁺ increases too much, the thermal stability of the glass decreases, the liquidus temperature tends to increase, the glass exhibits a blue-gray color, and the absorption edge in the spectral transmittance characteristics becomes longer. Accordingly, the content of W ⁶⁺ is preferably 19% or less. A more preferable upper limit of the content of W ⁶⁺ is 18%. Hereinafter, smaller values in the order of 17%, 16%, 15%, 14%, 13%, and 12% are more preferable as the upper limit value.

Bi ³⁺ is a component having a high refractive index and a high dispersion, and works to improve the thermal stability of the glass by containing an appropriate amount. When the content of Bi ³⁺ is too large, the thermal stability is lowered, the liquidus temperature is raised, the glass is colored brown, and the absorption edge in the spectral transmittance characteristic is lengthened. Therefore, the Bi ³⁺ content is preferably 33% or less. Hereinafter, smaller values in the order of 32%, 31%, 30%, 29%, and 28% are more preferable as the upper limit value. The preferable lower limit of the Bi ³⁺ content is 16%, and the higher the order of 17%, 18%, 19%, and 20%, the more preferable the lower limit value.

Te ⁴⁺ has a function of increasing the refractive index and the dispersion of the glass and improving the thermal stability of the glass. Considering the thermal stability of the glass, the Te ⁴⁺ content is preferably 0 to 4%. However, considering the environmental impact, the Te ⁴⁺ content is preferably small, and the content range is 0 to 2%. % Is more preferable, and 0 to 1% is more preferable. Te ⁴⁺ may not be contained.

Li ⁺ is an effective component for improving the meltability, lowering the melting temperature, and lowering the temperature at which the glass exhibits a viscosity of 1.0 dPa · s, and shortens the absorption edge in the spectral transmittance characteristics. At the same time, it suppresses the reduction of the high refractive index component during glass melting and functions to suppress coloring. However, if the Li ⁺ content is excessive, the refractive index tends to decrease and the thermal stability tends to decrease. Therefore, the Li ⁺ content is preferably 5% or less. A more preferable upper limit of the content of Li ⁺ is 4%, a more preferable upper limit is 3%, a still more preferable upper limit is 2%, and a more preferable upper limit is 1%. The minimum with preferable content of Li ^<+> is 0%, and a more preferable minimum is 0.1%. In addition, when importance is attached to the stability of glass, it is not necessary to contain Li ^<+> .

Na ⁺ improves the meltability without lowering the thermal stability of the glass, lowers the melting temperature, shortens the absorption edge in the spectral transmittance characteristics, and reduces the high refraction during glass melting. It functions to suppress reduction of the rate-increasing component and to suppress coloring. It also serves to lower the liquidus temperature. However, when the Na ⁺ content is excessive, the refractive index is lowered, and the thermal stability tends to be lowered. In order to improve the meltability and thermal stability of the glass while maintaining the high refractive index characteristics, the Na ⁺ content is preferably 0 to 15%. As for the upper limit of the Na ⁺ content, smaller values in the order of 13%, 10%, 8%, and 6% are more preferable as the upper limit. Since Na ⁺ has an ionic radius between Li ⁺ and K ⁺ , the action of lowering the refractive index is larger than Li ^{+ and} smaller than K ⁺ . The preferable lower limit of the Na ⁺ content is 0%, the more preferable lower limit is 0.5%, the still more preferable lower limit is 1.0%, the more preferable lower limit is 1.5%, and the still more preferable lower limit is 2.0%. .

K ⁺ also functions to improve the meltability and lower the melting temperature. In addition, the wavelength of the absorption edge in the spectral transmittance characteristics is shortened, and the reduction of the high refractive index component during glass melting is suppressed and coloring is also suppressed. Furthermore, compared with Li ^<+> and Na ^{< +>} , it improves the thermal stability and functions to lower the liquidus temperature. However, when the K ⁺ content is excessive, the refractive index decreases and the thermal stability tends to decrease. Therefore, the K ⁺ content is preferably 0 to 15%. A more preferable upper limit of the content of K ⁺ is 13%, a further preferable upper limit is 10%, and a still more preferable upper limit is 8%, and further 6%.

Rb ⁺ also has a function of improving the meltability and can be introduced into the glass as an optional component. However, since it is more expensive than other alkali metal components, the content of Rb ⁺ is preferably 0 to 2%, more preferably 0 to 1%, and 0 to 0.5%. More preferably.
Cs ⁺ can be introduced into the glass as an optional component because the glass is stabilized by introduction of a small amount. However, since it is more expensive than other alkali metal components, the content of Cs ⁺ is preferably 0 to 5%, more preferably 0 to 3%, 0 to 2%, 0 to More preferably, it is 1%.
Rb ⁺ and Cs ⁺ need not be contained.

In order to improve the meltability and suppress the corrosion of platinum, gold and the like, the total content of Li ⁺ , Na ⁺ and K ⁺ is preferably more than 0%, more preferably 0.2% or more. Preferably, it is more preferably 0.5% or more, still more preferably 1.0% or more, still more preferably 1.5% or more, and even more preferably 2.0% or more. Preferably, 2.5% or more is even more preferable. The introduction of the alkali metal component is also preferable from the viewpoint of suppressing the coloring of the glass due to the reduction of the high refractive index increasing component.
From the standpoint of maintaining the high refractive index characteristics and the thermal stability of the glass, the total content of Li ⁺ , Na ⁺ and K ⁺ is preferably 15% or less, more preferably 12% or less. % Or less, more preferably 8% or less, even more preferably 6% or less, still more preferably 5% or less, and even more preferably 4% or less. preferable.

B ³⁺ functions to improve the thermal stability and meltability of the glass, increase the viscosity, and lower the liquidus temperature by introducing an appropriate amount. However, the temperature at which the glass can be clarified increases due to the effect of increasing the viscosity of B ³⁺ , and as a result, the coloration degree of the produced glass tends to deteriorate. If the content is excessive, the refractive index decreases, the thermal stability associated with reheating of the glass decreases, the liquidus temperature increases, and the glass tends to accelerate coloring due to the reduction of the higher refractive index component. In the present invention, B ³⁺ is a component whose content should be reduced as much as possible. That is, the content of B ³⁺ is preferably 0 to 8%. The more preferable upper limit of the content of B ³⁺ is 6%, the more preferable upper limit is 4%, the more preferable upper limit is 2%, and the still more preferable upper limit is 1%. The minimum with preferable content of ^{B3 +} is 0% or more, and it is preferable not to contain ^{B3 +} from a viewpoint of reducing clarification viscosity.

Mg ²⁺ , Ca ²⁺ , Sr ²⁺ , Ba ²⁺ , and Zn ²⁺ all have a function of improving the meltability of the glass. However, since Mg ²⁺ , Ca ²⁺ , Sr ²⁺ , Zn ²⁺ tend to decrease the refractive index when the content of these components is increased, the content of Mg ²⁺ is preferably in the range of 0 to 4%. More preferably, it is in the range of 0 to 2%, more preferably in the range of 0 to 1%, and the content of Ca ²⁺ is preferably in the range of 0 to 4%, and the range of 0 to 2% More preferably, it is more preferably in the range of 0 to 1%, the Sr ²⁺ content is preferably in the range of 0 to 4%, more preferably in the range of 0 to 2%. The content of Zn ²⁺ is preferably in the range of 0 to 4%, more preferably in the range of 0 to 2%, and more preferably in the range of 0 to 1%. It is more preferable to make the range.
^{Incidentally, Mg 2+, Ca 2+, Sr} 2+, may not contain a ^{Zn 2+.}

Ba ²⁺ improves the thermal stability of the glass, improves the meltability, shortens the absorption edge in the spectral transmittance characteristics, and functions to suppress the coloring of the glass due to the reduction of the high refractive index component. However, although not as much as Mg ²⁺ , Ca ²⁺ , Sr ²⁺ , and Zn ²⁺ , the content is preferably not excessive from the viewpoint of maintaining high refractive index characteristics. In this respect, the Ba ²⁺ content is preferably in the range of 0 to 10%. The upper limit of the Ba ²⁺ content is more preferably 8%, still more preferably 7%, still more preferably 6%, and even more preferably 5%. The more preferable lower limit of the Ba ²⁺ content is 0%, the more preferable lower limit is 1%, the still more preferable lower limit is 2%, the still more preferable lower limit is 3%, and the still more preferable lower limit is 4%. From the viewpoint of optical characteristics, Ba ²⁺ may not be contained.

Si ⁴⁺ is a component that lowers the refractive index. Further, since excessive introduction causes an increase in the liquidus temperature of the glass or phase separation of the glass, the content of Si ⁴⁺ is preferably 0 to 4%, more preferably 0 to 2%. More preferably, it is set to ˜1%. Although Si ⁴⁺ is mainly introduced by an ordinary oxide raw material, it can be mixed from a crucible (quartz crucible) made of a material mainly composed of SiO ₂ .

Since Al ^{3+ functions} to lower the refractive index and raise the liquidus temperature of the glass, the content of Al ³⁺ is preferably in the range of 0 to 3%, preferably in the range of 0 to 1%. Is more preferable. In addition, it is not necessary to contain ^{Al3 +} .

From the standpoint of maintaining the meltability and thermal stability of the glass while maintaining the refractive index nd exceeding 2.02, P ⁵⁺ , Bi ³⁺ , Nb ⁵⁺ , Ti ⁴⁺ , W ⁶⁺ , Li ⁺ , Na ⁺ , K The total content of ⁺ , B ³⁺ , Si ⁴⁺ and Ba ²⁺ is preferably 90 to 100%, more preferably 95 to 100%, still more preferably 98 to 100%, and 99 to 100 % Is more preferable. The total content may be 100%.

A clarifying agent may be added to the optical glass of the present invention. Among the fining agents, preferred is Sb ₂ O ₃ . When using the Sb ₂ O _3, it is preferable to set the outer split amount of _Sb 2 _{O 3} by mass ratio in the range of 0 to 10,000 ppm. In addition, the extra split addition amount by mass ratio is an addition amount shown by the ratio on the basis of the mass of a glass component. In addition to having a clarification effect, Sb ₂ O ₃ functions to make the above-described high refractive index component in an oxidized state and stabilize this oxidized state during glass melting. However, when the external addition amount exceeds 10,000 ppm, the glass tends to be colored due to light absorption of Sb itself. From the viewpoint of improving the transmittance characteristics of the glass, the preferable upper limit of the external addition amount of Sb ₂ O ₃ is 5000 ppm, the more preferable upper limit is 2000 ppm, the further preferable upper limit is 1100 ppm, the more preferable upper limit is 900 ppm, and the more preferable upper limit is An even more preferable upper limit is 400 ppm, a preferable lower limit is 0 ppm, a more preferable lower limit is 50 ppm, a still more preferable lower limit is 100 ppm, a still more preferable lower limit is 150 ppm, and a still more preferable lower limit is 200 ppm. In addition, since Sb is an additive, in the present invention, the addition amount is shown as an oxide-converted value, unlike the glass component.

In the optical glass of the present invention, it is desirable that any of cations of Pb, As, Cd, Tl, and Se is not contained or added in consideration of environmental load. In addition, V, Cr, Mn, Fe, Co, Ni, Cu, Pr, Nd, Eu, Tb, Ho, and Er cations are all contained in the glass or fluorescent when irradiated with ultraviolet light. It is desirable not to add. However, the inclusion and addition of the above does not exclude even mixing as impurities derived from the glass raw material or the glass melting step.
Ga ³⁺ , La ³⁺ , Gd ³⁺ , Y ³⁺ , Yb ³⁺ , Lu ³⁺ , In ³⁺ , Ge ⁴⁺ and Hf ⁴⁺ may be contained in small amounts, but a significant effect can be obtained by these components. Since both are expensive components, the content is preferably in the range of 0 to 2%, more preferably in the range of 0 to 1%, and 0% or more and 0.5%. More preferably, it is more preferably 0% or more and less than 0.1%, and it is desirable not to contain it in order to reduce the manufacturing cost of the glass.

[Refractive index, Abbe number]
Next, the glass characteristics of the optical glass of the present invention will be described in detail.
The refractive index nd of the optical glass of the present invention is 2.02 or more. Thus, the optical glass having a very high refractive index is suitable as a material for an optical element for constituting a high zoom ratio, wide angle, and compact optical system. The upper limit of the refractive index nd is naturally determined from the range of the glass composition, but can be 3.0 as a guide.
In addition, from the viewpoint of providing an optical glass used for an effective optical element by increasing the functionality of the optical system and making it compact, a preferable lower limit of the refractive index nd is 2.03, a more preferable lower limit is 2.05, and a further preferable lower limit. Is 2.07.
In order to maintain the meltability and thermal stability of the glass, the preferable upper limit of the refractive index nd is 2.3, the more preferable upper limit is 2.2, the still more preferable upper limit is 2.18, and the more preferable upper limit is 2.16. is there.

The upper limit of the Abbe number νd is preferably 18.0, more preferably 17.8, still more preferably 17.6, and still more preferably 17 in terms of correcting chromatic aberration by combining with an optical element made of low dispersion glass. .4, an even more preferred upper limit is 17.2, and an even more preferred upper limit is 17.1.
The lower limit of the Abbe number νd is naturally determined from the range of the above glass composition. From the viewpoint of maintaining the meltability and thermal stability of the glass, the preferred lower limit of the Abbe number νd is 14, a more preferred lower limit is 15, and a more preferred lower limit. Is 16.

From the viewpoint of obtaining a glass suitable for correcting chromatic aberration, a preferable range of refractive index nd and Abbe number νd is a range satisfying the following formula (1), and a more preferable range is a range satisfying the following formula (2), and further preferable. The range is a range that satisfies the following formula (3), a more preferable range is a range that satisfies the following formula (4), and a still more preferable range is a range that satisfies the following formula (5).
νd <39.00-10 × nd (1)
νd <38.80-10 × nd (2)
νd <38.60-10 × nd (3)
νd <38.40-10 × nd (4)
νd <38.20-10 × nd (5)

[Viscosity characteristics]
In a preferred embodiment of the optical glass of the present invention, the temperature at which the viscosity is 1.0 dPa · s in the glass melt state is 1100 ° C. or lower. At the time of glass production, the refining temperature of the molten glass is a temperature at which the viscosity shows 1.0 dPa · s. And since the refining temperature is the temperature at which the temperature of the glass becomes highest during glass melting, when the temperature is 1100 ° C. or lower, the glass melting step can be performed at 1100 ° C. or lower. As a result, the erodibility of the molten glass is reduced, and a metal melting vessel such as platinum and gold is less likely to be eroded by the glass, increasing the coloring of the glass due to the penetration of platinum ions, gold ions, etc., Ti, Nb, W, An increase in coloration due to reduction of a high refractive index component such as Bi can be suppressed. Thus, it is possible to obtain an optical glass that is sufficiently blown out and optically homogeneous and less colored.
Moreover, by suppressing the raise of the refining temperature, volatilization from molten glass can be suppressed, and the composition change by a volatilization and the fluctuation | variation of an optical characteristic can also be suppressed.
A preferable range of the temperature at which the viscosity is 1.0 dPa · s in the glass melt state is 1080 ° C. or less, a more preferable range is 1060 ° C. or less, a preferable range is 1050 or less, a further preferable range is 1040 ° C. or less, and a more preferable range is 1030. C. or lower, and a more preferable range is 1020 C or lower. Although the lower limit of the temperature indicating 1.0 dPa · s is naturally determined from the composition range of the glass, 800 ° C. may be considered as a guideline for the lower limit.

[Liquid phase temperature]
The liquidus temperature tends to increase with increasing the refractive index and dispersion of the glass. When the liquidus temperature rises, the melting temperature and the molding temperature are raised in order to prevent devitrification during glass production. A preferable range of the liquidus temperature of the optical glass of the present invention is a range of 1100 ° C. or lower. By setting the liquidus temperature within the above range, an excessive increase in the melting temperature and the molding temperature can be suppressed. In the glass manufacturing process, the liquid phase temperature is within the above range in order to prevent platinum and gold, which are melting container materials, from being melted into the glass and coloring the glass, or from mixing platinum and gold as foreign substances and deteriorating the quality of the glass. It is preferable to make it. The more preferred upper limit of the liquidus temperature is 1050 ° C., the more preferred upper limit is 1000 ° C., the more preferred upper limit is 980 ° C., the still more preferred upper limit is 960 ° C., the still more preferred upper limit is 950 ° C., and the still more preferred upper limit is 940 ° C. The preferred upper limit is 930 ° C, and the most preferred upper limit is 920 ° C.
Note that the lower limit of the liquidus temperature can be considered with 800 ° C. or more, more preferably 850 ° C. or more as a guideline from the viewpoint of containing a high refractive index component having a high melting point.
The viscosity of the glass at the liquidus temperature is preferably 1.0 dPa · s or more, more preferably 1.5 dPa · s or more, further preferably 2.0 dPa · s or more, and 2.5 dPa · s. -It is more preferable that it is s or more, it is still more preferable that it is 3.0 dPa * s or more, and it is still more preferable that it is 3.5 dPa * s or more.
The upper limit of the viscosity of the glass at the liquidus temperature is not particularly limited, but is preferably 100 dPa · s or less, more preferably 30 dPa · s or less, more preferably 20 dPa from the viewpoint of improving the optical properties of the glass. -More preferably, it is s or less.

[Coloring degree]
In general, in the spectral transmittance characteristics of optical glass, as an index indicating how far a short wavelength light is transmitted, a wavelength such as λ70 indicating a wavelength of 70% external transmittance and λ5 indicating a wavelength of 5% external transmittance are specified. An index by wavelength is used.
λ70 is a wavelength at which the light transmittance is 70% in the wavelength range of 280 to 700 nm. Here, the light transmittance means that a glass sample having parallel surfaces polished to a thickness of 10.0 ± 0.1 mm is used, and light is incident on the polished surface from a vertical direction. The obtained spectral transmittance, that is, Iout / Iin where Iin is the intensity of light incident on the sample and Iout is the intensity of light transmitted through the sample. The spectral transmittance includes light reflection loss on the sample surface. Moreover, the said grinding | polishing means that the surface roughness is smooth | blunted in the state small enough with respect to the wavelength of a measurement wavelength range. λ5 is a wavelength at which the light transmittance measured by the method described above for λ70 is 5%.
As described above, the conventional high refractive index glass tends to be easily colored in melting and refining. However, in the preferred embodiment of the optical glass of the present invention, λ70 of 550 nm or less is realized while the refractive index nd is 2.02 or more. can do. A more preferable range of λ70 is 520 nm or less, a further preferable range is 500 nm or less, a more preferable range is 490 nm or less, a still more preferable range is 480 nm or less, a still more preferable range is 470 nm or less, and a still more preferable range is 460 nm or less. The lower limit of λ70 is not particularly limited, but 380 nm may be considered as a guideline for the lower limit of λ70.
A preferable range of λ5 is 450 nm or less, a more preferable range is 430 nm or less, a further preferable range is 410 nm or less, a more preferable range is 400 nm or less, a still more preferable range is 395 nm or less, and an even more preferable range is 390 nm or less. The lower limit of λ5 is not particularly limited, but 300 nm may be considered as a guideline for the lower limit of λ5.
According to the present invention, it is possible to provide an optical glass that is not only less colored but also contains very little contamination due to ionization or contamination as a metal particle of a metallic material such as platinum or gold.

[specific gravity]
In the present invention, the specific gravity is defined by the specific gravity of the glass obtained at a slow cooling rate of −30 ° C./hour. The preferred upper limit of the specific gravity of the optical glass of the present invention is 6.5, the more preferred upper limit is 5.9, the still more preferred upper limit is 5.8, the more preferred upper limit is 5.7, and the still more preferred upper limit is 5.65. The preferred lower limit is not particularly limited, but if the specific gravity is excessively lowered, a phenomenon such as a decrease in the refractive index may occur. Therefore, the preferred lower limit of the specific gravity is 3.0, and the more preferred lower limit is 4.0. The preferred lower limit is 4.5, the more preferred lower limit is 4.8, and the still more preferred lower limit is 5.0.

Method for Producing Optical Glass The method for producing an optical glass of the present invention comprises melting a glass raw material by heating, clarifying the obtained molten glass, and forming a clarified molten glass. It mix | blends so that the optical glass of this invention is obtained.
Hereinafter, although specific loan of the manufacturing method of the optical glass of this invention is demonstrated, this invention is not limited to the following aspect.

For example, the compound raw materials corresponding to each component are weighed so as to become a glass having a required composition, mixed well to prepare a mixed raw material, and the mixed raw material is placed in a crucible and stirred at 1050 to 1250 ° C. with 0.5 to After melting for 3 hours, the glass melt is poured into a predetermined container, cooled and pulverized to obtain cullet.
Next, the obtained cullet is put into a crucible made of noble metal such as platinum, platinum alloy, gold, gold alloy, and heated to a liquidus temperature LT to LT + 80 ° C., preferably a liquidus temperature LT to LT + 50 ° C., and stirred. And melted. Next, the molten glass is clarified at a temperature ± 50 ° C. at which the glass exhibits 1.0 dPa · s, preferably at a temperature ± 20 ° C. at which the glass exhibits 1.0 dPa · s over 0.5 to 3 hours. After clarification, the glass temperature is changed from the clarification temperature to the liquidus temperature LT to LT + 80 ° C, preferably the liquidus temperature LT to LT + 50 ° C, more preferably the liquidus temperature LT to LT + 40 ° C, and more preferably the liquidus temperature LT to LT + 30 ° C. After the temperature is lowered, molten glass is allowed to flow out from a pipe connected to the bottom of the crucible, or cast into a mold and molded to obtain optical glass. The set temperature when using a gold noble metal crucible is set to 1050 ° C. or lower, which is lower than the melting point of gold.
The temperature conditions and the time required for each step can be adjusted as appropriate.
It is also possible to produce a plurality of types of cullet having different optical characteristics by the above-described method, prepare these cullets so as to obtain the required optical characteristics, and melt, clarify, and shape the optical glass.

Glass material for press molding The glass material for press molding of the present invention (hereinafter referred to as glass material) is composed of the optical glass of the present invention described above. In order to obtain the glass material of the present invention, for example, first, a glass material prepared so as to obtain the optical glass of the present invention is heated, melted and molded. The glass molded body thus produced is processed to produce a glass material corresponding to the amount of one press-formed product. Other than this method, a known method for producing a glass material for press molding from molten glass can be applied.

Optical element, method for producing optical element The optical element of the present invention comprises the optical glass of the present invention described above.
The optical element manufacturing method of the present invention is obtained by processing the optical glass of the present invention described above or by manufacturing the optical glass by the above-described optical glass manufacturing method of the present invention and processing the manufactured optical glass. To obtain an optical element.
Specific examples of optical elements include aspherical lenses, spherical lenses, or plano-concave lenses, plano-convex lenses, biconcave lenses, biconvex lenses, convex meniscus lenses, concave meniscus lenses, micro lenses, lens arrays, lenses with diffraction gratings, etc. Various lenses, prisms, prisms with lens functions, and the like can be exemplified. If necessary, an antireflection film, a wavelength selective partial reflection film, or the like may be provided on the surface.
Since the optical element of the present invention is made of optical glass having ultrahigh refractive index characteristics, it can be favorably corrected by combining with an optical element made of other glass. It is also effective in increasing the zoom ratio, wide angle, and compactness of the imaging optical system. Furthermore, since the increase in specific gravity can be suppressed by adjusting the composition while having an ultrahigh refractive index characteristic, it is possible to reduce the weight of the optical element, and it is also effective in preventing the deviation of the focal position with respect to vibration.
In addition, the use of glass with a shorter absorption edge in the spectral transmittance characteristics can prevent loss of image information in the visible short wavelength region, and is also effective in improving the color reproducibility of digital imaging devices. .
The optical element of the present invention includes an imaging optical system of various cameras such as a digital still camera, a digital video camera, a surveillance camera, and an in-vehicle camera, an optical element that guides a light beam for writing and reading data on an optical recording medium such as a DVD and a CD, For example, it is also suitable for an optical pickup lens or a collimator lens. It is also suitable as an optical element for optical communication.

  Processing for obtaining an optical element can be performed by a known method such as precision press molding, grinding, polishing, or the like. For example, a method of polishing the surface of a molded product obtained by molding the optical glass of the present invention, a glass material for press molding of the present invention is heated and press-molded to produce an optical element blank. The optical element can be produced by a known method such as a method of grinding and polishing, a method of heating the glass material for press molding of the present invention and precision press molding to form an optical element.

  Hereinafter, the present invention will be further described by examples. However, the present invention is not limited to the embodiment shown in the examples.

Example 1
No. shown in Table 1. The compound raw material corresponding to each component was weighed so as to obtain a glass having a composition of 1 to 14, and mixed well to obtain a blended raw material. The glass composition shown in Table 1 is based on the cation% value. In addition, No. The total amount of the anion component of the oxide glass having the composition of 1 to 14 is O ²⁻ .
Next, the prepared raw material was put in a quartz crucible and melted for 0.5 to 1.5 hours while stirring at 1100 ° C. to 1200 ° C., and then rapidly cooled and pulverized to obtain cullet.
Next, the obtained cullet was put into a platinum or gold noble metal crucible, heated to a liquidus temperature LT + 20 ° C. to LT + 80 ° C., stirred and melted. Next, the molten glass was clarified at a temperature ± 50 ° C. at which the glass exhibits 1.0 dPa · s, preferably at a temperature ± 20 ° C. at which the glass exhibits 1.0 dPa · s over 0.5 to 3 hours. After clarification, the temperature of the glass was lowered from the clarification temperature to the liquidus temperature LT to LT + 60 ° C., and then the molten glass was discharged from a pipe connected to the bottom of the crucible or cast into a mold to form a glass block. The set temperature when using a gold precious metal crucible was set to 1050 ° C. or lower, which is lower than the melting point of gold.
When light was incident on each of the obtained glass blocks and the optical path of the light in the glass was observed from the side, no foreign substances such as crystals were observed in the glass, and high-quality optical glass with high homogeneity was obtained. It was confirmed that

The obtained optical glass No. For 1 to 14, the refractive index nd, Abbe number νd, liquidus temperature, temperature showing a viscosity of 1.0 dPa · s, glass transition temperature, specific gravity, λ70, λ5 were measured as follows.
(1) Refractive index nd and Abbe number νd
It measured based on Japan Optical Glass Industry Association standard JOGIS-01. The measurement results are shown in Table 1.
(2) Temperature indicating liquidus temperature LT and viscosity of 1.0 dPa · s A glass sample is placed in a furnace heated to a predetermined temperature and held for 2 hours. After cooling, the inside of the glass is observed with a 100 × optical microscope. The liquidus temperature was determined from the presence or absence of crystals. Viscosity JIS standard Z8803, the viscosity was measured by a viscosity measuring method using a coaxial double cylindrical rotational viscometer, and a temperature showing a viscosity of 1.0 dPa · s was determined.
(3) Glass transition temperature Tg
The glass transition temperature was measured from the endothermic curve when the temperature of the solid glass was raised using a differential scanning calorimeter DSC3300SA. Tg measured by this measuring method shows a correspondence relationship with Tg measured based on Japan Optical Glass Industry Association Standard JOGIS-08. The measurement results are shown in Table 1.
(4) Specific gravity Measured based on Japan Optical Glass Industry Association Standard JOGIS-05. The measurement results are shown in Table 1.
(5) λ70, λ5
λ70 and λ5 were measured as follows. Spectral transmittances in a wavelength range from 280 nm to 700 nm are measured using glass samples having a plane parallel to each other and optically polished having a thickness of 10 mm. The spectral transmittance is calculated by B / A by measuring the intensity B of a light beam incident on an optically polished plane perpendicular to one plane and exiting from the other plane. Therefore, the spectral transmittance includes a reflection loss of light rays on the sample surface. The wavelength at which the spectral transmittance is 70% is λ70, and the wavelength at which the spectral transmittance is 5% is λ5. The measurement results are shown in Table 1.

(Example 2)
In the same manner as in Example 1, optical glass no. The glass raw material was heated, melted, clarified and homogenized so that 1 to 14 were obtained, and the obtained molten glass was poured into a mold and rapidly cooled to form glass black. Next, after annealing the glass block, it was cut and ground to produce a glass material for press molding.

(Example 3)
The glass material for press molding produced in Example 2 was heated and softened, and was press-molded by a known method using a press mold to produce optical element blanks such as a lens blank and a prism blank.
The obtained optical element blank was subjected to precision annealing to precisely adjust the refractive index so as to have a required refractive index, and then finished into a lens or a prism by known grinding and polishing methods.

Example 4
The surface of the glass material for press molding produced in Example 2 was polished to obtain a glass material for press molding for precision press molding, and this glass material was heated and precision press molded to obtain an aspheric lens. Precision press molding was performed by a known method.
In this way, optical elements such as various lenses and prisms were produced.

When the imaging optical system was configured using the lenses obtained in Examples 3 and 4, an imaging device with good color reproducibility could be obtained.
Moreover, when an imaging unit or an optical pickup unit mounted on a mobile phone was produced using the obtained lens, a unit with extremely small focal position deviation with respect to vibration could be obtained.
The optical element of the present embodiment enables good chromatic aberration correction when combined with a low dispersion glass optical element. In addition, it is effective for improving the performance and compactness of various optical devices including imaging devices.

  The present invention can provide an optical glass having a high refractive index suitable as an optical element material for correcting chromatic aberration, and further can provide a glass material for press molding and an optical element using the optical glass. .

That is, the above object was achieved by the following means.
[1] As a cation component,
10 to 40 cation% of P ⁵⁺
Ti ⁴⁺ , Nb ⁵⁺ , W ⁶⁺ , Bi ³⁺ and Te ⁴⁺ total 50 cation% or more (however, the sum of Ti ⁴⁺ and Nb ^{5+ with} respect to the total content of W ⁶⁺ and Bi ³⁺ Cation ratio of content ((Ti ⁴⁺ + Nb ⁵⁺ ) / (W ⁶⁺ + Bi ³⁺ )) is 1.3 or less),
B ³⁺ , Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ , Mg ²⁺ , Ca ²⁺ , Sr ²⁺ , Ba ²⁺ and Zn ²⁺ in total, Ti ⁴⁺ , Nb ⁵⁺ , 1/3 or less of the total content of W ⁶⁺ , Bi ³⁺ and Te ⁴⁺ ,
Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ and Cs ⁺ in total exceeding 0%,
An optical glass having a refractive index of 2.02 or more.
[2] The optical glass according to [1], containing 0 to 4 cation% of Te ⁴⁺ as a cation component .
[ 3 ] The optical glass according to [1] or [2] , wherein the Abbe number νd is 18.0 or less.
[ 4 ] In a method for producing optical glass, comprising melting a glass raw material by heating, refining the obtained molten glass, and forming a clarified molten glass.
A method for producing an optical glass, wherein the glass raw material is prepared such that the optical glass according to any one of [1] to [3] is obtained.
[ 5 ] The method for producing an optical glass according to [ 4 ], wherein the melting is performed using a molten glass container prepared using platinum, a platinum alloy, gold, or a gold alloy.
[ 6 ] A glass material for press molding comprising the optical glass according to any one of [1] to [3] .
[ 7 ] An optical element made of the optical glass according to any one of [1] to [3] .
[ 8 ] By processing the optical glass according to any one of [1] to [3] , or by manufacturing the optical glass by the method according to [ 4 ] or [ 5 ], the manufactured optical glass is processed. By this, the manufacturing method of the optical element which obtains an optical element.

Claims (7)

As a cation component,
10 to 40 cation% P ⁵⁺
Ti ⁴⁺ , Nb ⁵⁺ , W ⁶⁺ , Bi ³⁺ and Te ⁴⁺ total 50 cation% or more (provided that the cation ratio of the total content of Ti ⁴⁺ and Nb ^{5+ to} the total content of W ⁶⁺ and Bi ³⁺ ((Ti ⁴⁺ + Nb ⁵⁺ ) / (W ⁶⁺ + Bi ³⁺ )) is 1.3 or less)
B ³⁺ , Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ , Mg ²⁺ , Ca ²⁺ , Sr ²⁺ , Ba ²⁺ and Zn ²⁺ in total, Ti ⁴⁺ , Nb ⁵⁺ , W ⁶⁺ , Bi ³⁺ and Te ⁴⁺ 1/3 or less of the total content of
Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ and Cs ⁺ in total exceeding 0%,
An optical glass having a refractive index of 2.02 or more. The optical glass according to claim 1, wherein the Abbe number νd is 18.0 or less. In a method for producing optical glass, comprising melting a glass raw material by heating, clarifying the obtained molten glass, and forming a clarified molten glass,
The method for producing optical glass, wherein the glass raw material is prepared so that the optical glass according to claim 1 or 2 is obtained. The manufacturing method of the optical glass of Claim 3 which performs the said melting using the molten glass container produced using platinum, a platinum alloy, gold | metal | money, or a gold alloy. A glass material for press molding comprising the optical glass according to claim 1. An optical element made of the optical glass according to claim 1. An optical element obtained by processing the optical glass according to claim 1 or 2 or by producing the optical glass by the method according to claim 3 or 4 and processing the produced optical glass. Production method.