KR20110065490A - Optical glass and method for suppressing the deterioration of spectral transmittance - Google Patents

Abstract

The optical glass by which time-dependent deterioration of spectral transmittance was suppressed, and the method of suppressing deterioration of the spectral transmittance of glass are obtained. The optical glass has a content of Sb ₂ O _{3 in a} mass% of 0.5% or less and a solarization (deterioration in spectral transmittance at a wavelength of 450 nm) of 5.0% or less with respect to the total glass mass of the oxide conversion composition. In addition, the deterioration suppressing method of the spectral transmittance of the glass is to reduce the content of Sb ₂ O ₃ component contained in the glass.

Description

OPTICAL GLASS AND METHOD FOR SUPPRESSING THE DETERIORATION OF SPECTRAL TRANSMITTANCE}

The present invention relates to a method of suppressing deterioration of optical glass and spectral transmittance.

In recent years, the digitization and high precision of the apparatus which uses an optical system is progressing rapidly, and high precision and light weight with respect to optical elements, such as spherical lenses used for various optical apparatuses, such as a digital camera and a video camera, etc. , And the demand for miniaturization is becoming stronger.

In the manufacture of such an optical element, a method of grinding and polishing a molded glass obtained by heat-softening and shaping a glass material (reheat press molding), or by cutting a gob or a glass block, grinding And a method (precision press molding) in which a polished preform material or a preform material molded by known floating molding is heat-softened, and press-molded into a mold having a high-precision molding surface.

As glass used for such rich press molding and precision press molding, optical glass containing a SiO ₂ component, an Nb ₂ O ₅ component, and / or a TiO ₂ component is known. As such optical glass, glass having a composition as represented by Patent Literatures 1 and 2 is known. For example, Patent Document 1 shows an optical glass having a refractive index n _d of 1.63 to 1.75 and an Abbe's number (ν _d ) of 23 to 35. Moreover, the optical glass whose refractive index n _d is 1.80 or more and Abbe's number ((nu) _d ) is 30 or less is shown by patent document 2. As shown in FIG.

Japanese Patent Publication No. 2002-087841 Japanese Patent Publication No. 2004-155639

However, in the glass disclosed by patent documents 1 and 2, there existed a problem of the solarization in which the spectral transmittance falls by the ultraviolet-ray contained in sunlight and the like. Since glass with large solarization is colored by ultraviolet irradiation for a long time, it was difficult to maintain the desired spectral transmittance at the time of manufacture.

The objective of this invention was made in view of the said problem, Comprising: It aims at obtaining the optical glass which suppressed the deterioration of spectral transmittance with time, and the method of suppressing deterioration of spectral transmittance.

The inventors of the Pt component and / or Fe ingredients result of intensive testing and research in order to solve the above problems, reducing the content of Sb ₂ O ₃ component contained in the optical glass, and incorporated in and more preferably an optical glass By adjusting the content, it was found that the solarization of the optical glass was reduced, and the present invention was completed. Specifically, the present invention provides the following.

(1) and with respect to the glass the total mass of the oxide in terms of composition, the content of Sb ₂ O ₃ component in weight percent less than 0.5%, solarization (deterioration amount of the spectral transmittance at a wavelength of 450nm), an optical glass is not more than 5.0%.

(2) Optical glass as described in (1) whose content of @Pt component is 15 ppm or less.

(3) Optical glass as described in (1) or (2) whose content of Fe component is 50 ppm or less with respect to the glass total mass of a xoxide conversion composition.

(4) The optical glass according to any one of the SiO ₂ component, and Nb ₂ O ₅ component, and / or (1) to (3) containing the TiO ₂ component.

(5) against the glass the total mass of the oxide in terms of composition, and the SiO ₂ component in terms of mass% containing 1.0% or more and 60.0% or less, and Nb ₂ O ₅ component than 65.0% to 10.0%, the content of the TiO ₂ ingredient 40.0 The optical glass as described in (4) which is% or less.

(6) By mass% with respect to the total glass mass of oxide conversion composition

0-20.0% of B ₂ O ₃ component, and / or

0-30.0% GeO ₂ component, and / or

0-25.0% Al ₂ O ₃ component, and / or

ZrO ₂ component 0-20.0%, and / or

Ta ₂ O ₅ component 0-20.0%, and / or

WO ₂ component 0-20.0%, and / or

ZnO component 0-30.0%, and / or

MgO component 0-20.0%, and / or

CaO component: 0-30.0%, and / or

SrO component 0-30.0%, and / or

BaO component: 0 to 30.0%, and / or

0-20.0% Li ₂ O component, and / or

Na ₂ O component 0-30.0%, and / or

The optical glass according to any one of the K ₂ O component 0 ~ 20.0% of (1) to (5).

(7) By mass% with respect to the total glass mass of oxide conversion composition

La ₂ O ₃ component 0-50.0%, and / or

0-30.0% Gd ₂ O ₃ component, and / or

Y ₂ O ₃ component 0-30.0%, and / or

0-20.0% Ga ₂ O ₃ component, and / or

0-50.0% TeO ₂ component, and / or

0-50.0% of Bi ₂ O ₃ component, and / or

The optical glass according to any one of the CeO ₂ component 0 ~ 10.0% of (1) to (6).

(8) between the partial dispersion ratio (θg, F) with the Abbe number (ν _d), in the range of ^{_{ν d ≤25 (-1.60 × 10 -3}} × ν d +0.6346) ≤ (θg, F) ≤ (−4.21 × 10 ⁻³ × ν _d +0.7207), satisfying the relationship, and in the range of ν _d > 25, (−2.50 × 10 ⁻³ × ν _d +0.6571) ≦ (θ g, F) ≦ the optical glass according to any one of _{^{(-4.21 × 10 -3 × ν d}} +0.7207) (1) to (7), satisfy the following relations.

(9) Optical glass in any one of (1)-(8) whose glass transition point (Tg) is 400 degreeC or more and 650 degrees C or less.

The optical element which uses the optical glass as described in any one of (10) '(1)-(9) as a base material.

(11) Lens preform consisting of the optical glass according to any one of (1) to (9).

The lens preform for mold press molding which consists of an optical glass in any one of (12) '(1)-(9).

The optical element formed by shape | molding the lens preform as described in (13) '(11) or (12).

(14) A method of suppressing deterioration in spectral transmittance as a method of suppressing deterioration in spectral transmittance of glass, wherein the content of Sb ₂ O ₃ component contained in glass is reduced.

According to the present invention, by reducing the content of the Sb ₂ O ₃ component contained in the optical glass, and more preferably by adjusting the content of the Pt component and / or Fe component to be mixed in the optical glass, by long-term irradiation of ultraviolet A method of suppressing deterioration of optical glass and spectral transmittance in which solarization of the optical glass is reduced can be obtained.

1 is a diagram showing a relationship between the content and solarization of Sb ₂ O ₃ ingredient.
Figure 2 is a graph showing the relation between the content of the solarization, Pt component in each of the Sb ₂ O ₃ ingredient content.
3 is a diagram showing the relationship between the content of the Fe component and the solarization.

In the optical glass of the present invention, the content of the Sb ₂ O ₃ component is 0.5% or less with respect to the total glass mass of the oxide conversion composition, and the solarization (deterioration amount of the spectral transmittance at a wavelength of 450 nm) is 5.0% or less. By reducing the content of Sb ₂ O ₃ component contained in the optical glass is reduced solarization of the glass. For this reason, the optical glass and optical element by which time-dependent deterioration of spectral transmittance was suppressed can be obtained.

In addition, the deterioration suppressing method of the spectral transmittance of the glass of the present invention to reduce the content of Sb ₂ O ₃ component contained in the glass. The solarization of the optical glass can be reduced by reducing the content of Sb ₂ O ₃ component contained in the glass. For this reason, the lens preform and optical element in which time-dependent deterioration of spectral transmittance was suppressed can be manufactured more reliably.

EMBODIMENT OF THE INVENTION Hereinafter, although embodiment of the optical glass of this invention and the method for suppressing deterioration of spectral transmittance is described in detail, this invention is not limited to the following embodiment at all, It changes within the range of the objective of this invention suitably, Can be added. In addition, about the place where description overlaps, description may be abbreviate | omitted suitably, but it does not limit the meaning of invention.

[Optical glass]

First, the component and the physical property of the optical glass of this invention are demonstrated. In addition, the glass used by the method for suppressing deterioration of the spectral transmittance of the present invention is not particularly limited as long as the content of the Sb ₂ O ₃ component is less than or equal to the predetermined amount, and among these, the glass that is described below is preferable.

Hereinafter, the composition range of each component which comprises the optical glass of this invention is described below. In this specification, when there is no notice in particular, content of each component shall be represented by the mass% with respect to the glass total mass of oxide conversion composition. Here, the "oxide conversion composition" means the total mass of oxides produced when it is assumed that all oxides, complex salts, metal fluorides, and the like, which are used as raw materials for the glass constituents of the present invention, are decomposed upon melting to change into oxides. Is 100 mass%, and it is the composition which described each component contained in glass.

<About components which should suppress content>

First, the component which should suppress content in the optical glass of this invention is demonstrated.

The Sb ₂ O ₃ component is a component having a defoaming effect when the glass is melted, but becomes a factor in which the solarization of the optical glass is enhanced by irradiation of ultraviolet rays. In particular, as shown in Fig. 1, since the content of the Sb ₂ O ₃ component is 0.5% or less, the solarization tends to be reduced to 5.0% or less, so that it is easy to obtain an optical glass that is hard to deteriorate in spectral transmittance even when used for a long time. There is a number. Therefore, the content of Sb ₂ O ₃ component to the entire mass of the glass composition in terms of oxide is preferably 0.5%, preferably from 0.3 percent, and most preferably from 0.2% as the upper limit. There is no technical disadvantage in particular if the content of the Sb ₂ O ₃ component is within this range. However, as shown in FIG. 1, the content of the Sb ₂ O ₃ component is made greater than 0% so as not to contain the Sb ₂ O ₃ component. The solarization can be lowered than when not. Therefore, the content of Sb ₂ O ₃ component to the entire mass of the glass composition in terms of oxide is preferably more than the 0%, and the more preferably 0.0001%, and most preferably from 0.001% as the lower limit. Sb ₂ O ₃ component is, for example, as a raw material can be used, and _{Sb 2 O 3, Sb 2 O} 5, Na 2 H 2 Sb 2 O 7 · 5H 2 O.

The Pt component is a component to be mixed into the optical glass from a member such as a platinum crucible when producing the optical glass, for example. However, the Pt component is a factor that increases the solarization of the optical glass by irradiation with ultraviolet rays. In particular, as shown in Fig. 2, since the solarization tends to be reduced by the content of the Pt component of the optical glass of 15 ppm or less, it is possible to easily obtain an optical glass whose spectral transmittance hardly changes even when used for a long time. Therefore, content of Pt component in optical glass becomes like this. Preferably it is 15 ppm, More preferably, it is 10 ppm, Most preferably, 7 ppm is an upper limit. A Pt component is a component contained in optical glass by elution from members containing platinum, such as a platinum crucible, even if it does not contain a Pt component as a material. Therefore, the amount of mixing in the optical glass can be reduced by, for example, shortening the melting time of the glass in the platinum crucible or lowering the melting temperature of the glass. Further, in addition to the suppression of the content of Fig. As shown, the Pt component 2, Sb ₂ O _3, by performing a content inhibition of the components at the same time, is apt to solarization of the optical glass is further reduced. In this case also it is possible to decrease the solarization compared with the case by increasing the content of Sb ₂ O ₃ ingredient than 0%, but not containing Sb ₂ O ₃ ingredient.

The Fe component is a component to be mixed in the optical glass, for example, as an impurity of the raw material of the optical glass when producing the optical glass, but it is a factor that increases the solarization of the optical glass by irradiation of ultraviolet rays. In particular, as shown in Fig. 3, since the content of the Fe component is 50 ppm or less, the solarization is easily reduced to 5.0% or less, and thus it is possible to easily obtain an optical glass that hardly changes the spectral transmittance even when used for a long time. Therefore, content of Fe component with respect to the total glass mass of oxide conversion composition becomes like this. Preferably it is 50 ppm, More preferably, it is 10 ppm, Most preferably, 5 ppm is an upper limit. The Fe component can reduce the amount of mixing in the optical glass, for example, by selecting a raw material of the optical glass having less Fe component. In addition to suppressing the content of the Fe component, simultaneously suppressing the content of the Sb ₂ O ₃ component and the Pt component, the solarization of the optical glass is more easily reduced.

<About essential component and arbitrary component>

Next, the essential component and arbitrary components of glass which are used suitably as the optical glass of this invention are demonstrated.

The SiO ₂ component is an oxide that forms glass and is a useful component for forming the skeleton of the glass. In particular, when the content of the SiO ₂ component is 1.0% or more, since the network structure of the glass increases to the extent that stable glass is obtained, the devitrification resistance of the glass can be improved. On the other hand, when the content of the SiO ₂ component is set to 60.0% or less, the refractive index of the glass becomes less likely to be lowered, and thus an optical glass having a desired refractive index can be easily obtained. Therefore, the content of SiO ₂ component to the free total mass of the oxide in terms of composition, preferably preferably less than 1.0%, preferably 5.0%, and most preferably is 10.0% as the lower limit, preferably 60% more, Preferably, the upper limit is 50.0%, most preferably 40.0%. The SiO ₂ component can be contained in the glass using, for example, SiO ₂ , K ₂ SiF ₆ , Na ₂ SiF _6, or the like as a raw material.

The Nb ₂ O ₅ component is a component that lowers the partial dispersion ratio (θg, F) of the glass and increases the refractive index of the glass. In particular, by setting the content of the Nb ₂ O ₅ component to 65.0% or less, a decrease in the devitrification resistance can be suppressed and a glass having a desired dispersibility can be easily obtained. Therefore, the content of Nb ₂ O ₅ component to the entire mass of the glass composition in terms of oxide, preferably a 65.0%, preferably 60% more, most preferably 55.0% as an upper limit. Further, in the optical glass of the present invention, since the content of Nb ₂ O ₅ component to more than 10.0%, it is possible to easily obtain the refractive index and the partial dispersion ratio (θg, F) of the desired. Therefore, the content of Nb ₂ O ₅ component to the entire mass of the glass composition in terms of oxide, and a preferably 10.0%, more preferably 15.0%, most preferably from 20.0% as the lower limit. Nb ₂ O ₅ component, for example, as a raw material by using a Nb ₂ O ₅ can be contained in the glass.

TiO ₂ is a component to increase the refractive index of the glass, a component for lowering the Abbe number of the glass, and any components in the optical glass of the present invention. The content of the TiO ₂ component, since, in particular, to the internal transmittance in the short wavelength region of visible light (500nm or less) by deterioration difficult to less than 40.0%, it is possible to reduce the coloring of the glass. Therefore, the content of TiO ₂ component of the total mass of the glass composition in terms of oxide, and a preferably 40.0%, more preferably 30.0%, most preferably from 20.0% as an upper limit. In the optical glass of the present invention, does not contain TiO ₂ component, but can produce an optical glass the solarization is reduced, by containing the TiO ₂ component, it is possible to easily obtain a desired refractive index. Therefore, the content of TiO ₂ component of the total mass of the glass composition in terms of oxide is preferably more than 0%, and the more preferably 0.1%, most preferably from 1.0% as the lower limit. The TiO ₂ component can be contained in glass using TiO ₂ etc. as a raw material.

The B ₂ O ₃ component is an oxide forming glass, a useful component for forming the skeleton of the glass, and an optional component in the optical glass of the present invention. In particular, when the content of the B ₂ O ₃ component is 40.0% or less, the refractive index of the glass is less likely to decrease, and the internal transmittance in the short wavelength region of visible light is less likely to deteriorate. Therefore, the content of B ₂ O ₃ component to the entire mass of the glass composition in terms of oxide, and a preferably 40.0%, more preferably 20.0%, most preferably from 10.0% as an upper limit. B ₂ O ₃ component is, for example, as a raw material using such as _{H 3 BO 3, Na 2 B} 4 O 7, Na 2 B 4 O 7 · 10H 2 O, BPO 4 can be contained in the glass. In addition, although the optical glass of the present invention do not contain B ₂ O ₃ component to produce an optical glass the solarization is reduced, by making the content of B ₂ O ₃ component to 0.1% or more, a substantial covered with the improved optical glass It can be easier to obtain. Therefore, the content of B ₂ O ₃ component to the entire mass of the glass composition in terms of oxide is preferably about 0.1%, preferably 0.5%, most preferably from 1.0% as the lower limit.

GeO ₂ component is any component in increasing the refractive index of the glass and a component which stabilizes the glass reduced devitrification (失透) at the time of molding, the optical glass of the present invention. In particular, when the content of the GeO ₂ component is 30.0% or less, the amount of the expensive GeO ₂ component is reduced, so that the material cost of the glass can be reduced. Therefore, the content of the GeO ₂ component to the entire mass of the glass composition in terms of oxide, and a preferably 30.0%, more preferably 20.0%, most preferably from 10.0% as an upper limit. GeO ₂ component can be contained in glass using GeO ₂ etc. as a raw material.

The Al ₂ O ₃ component is a component which improves the chemical durability of glass, and is an arbitrary component in the optical glass of this invention. Therefore, the content of Al ₂ O ₃ component to the entire mass of the glass composition in terms of oxides, and preferably the 15%, preferably 10% more, and most preferably from 5.0% as the upper limit. Al ₂ O ₃ component is, for example, as a raw material by using a Al ₂ O _3, Al (OH) _3, AlF ₃ can be contained in the glass.

The ZrO ₂ component is a component having the effect of lowering the liquidus temperature of the glass to improve the devitrification resistance, improving the chemical durability of the glass, and decreasing the partial dispersion ratio (θg, F) of the glass, and any of the optical glasses of the present invention. Ingredient. In particular, the chemical durability of the glass can be improved by setting the content of the ZrO ₂ component to 20.0% or less. Therefore, the content of the ZrO ₂ component of the total mass of the glass composition in terms of oxide is preferably 20.0%, preferably 15% more, most preferably 11% to the upper limit. ZrO ₂ component is, for example, as a raw material by using a ZrO _2, ZrF ₄ can be contained in the glass.

Ta ₂ O ₅ component to increase the refractive index of the glass, and lower the devitrification temperature of the glass component is any component in the optical glass of the present invention. In particular, it is possible to maintain the resistance to devitrification of the glass, by the content of Ta ₂ O ₅ component to less than 20.0%. Therefore, the content of Ta ₂ O ₅ component to the entire mass of the glass composition in terms of oxide, and a preferably 20.0%, more preferably 15.0%, most preferably from 10.0% as an upper limit. Ta ₂ O ₅ component, for example, as a raw material by using a Ta ₂ O ₅ can be contained in the glass.

WO ₃ is a component to increase the refractive index of the glass, and lower the devitrification temperature of the glass component is any component in the optical glass of the present invention. In particular, when the content of the WO ₃ component is 20.0% or less, the transmittance in the region of short wavelength (500 nm or less) of visible light, in particular, can be made difficult to deteriorate. Therefore, the content of WO ₃ components of the entire mass of the glass composition in terms of oxide, and a preferably 20.0%, more preferably 15.0%, most preferably from 10.0% as an upper limit. The WO ₃ component can be contained in glass using WO ₃ etc. as a raw material.

A ZnO component lowers the devitrification temperature of glass, lowers a glass transition point (Tg), and is an arbitrary component in the optical glass of this invention. In particular, the chemical durability of the glass can be improved by setting the content of the ZnO component to 30.0% or less. Therefore, content of ZnO component with respect to the total glass mass of oxide conversion composition becomes like this. Preferably it is 30.0%, More preferably, it is 20.0%, Most preferably, let 10.0% make an upper limit. ZnO is a component, for example, as a raw material using a ZnO, ZnF _2, etc. can be contained in the glass.

An MgO component is a component which lowers the melting temperature of glass, and is an arbitrary component in the optical glass of this invention. In particular, the chemical durability of glass can be improved by making content of MgO component into 20.0% or less. Therefore, content of MgO component with respect to the total glass mass of oxide conversion composition becomes like this. Preferably it is 20.0%, More preferably, it is 15.0%, Most preferably, let 10.0% make an upper limit. MgO component is, for example, as a raw material by using MgO, MgCO _3, MgF _2, etc. can be contained in the glass.

CaO component is a component which lowers the devitrification temperature of glass, and is an arbitrary component in the optical glass of this invention. In particular, the devitrification resistance of glass can be improved by making content of CaO component into 30.0% or less. Therefore, content of CaO component with respect to the total glass mass of oxide conversion composition becomes like this. Preferably it is 30.0%, More preferably, it is 20.0%, Most preferably, it makes an upper limit 10.0%. CaO component is, for example, as a raw material using a CaCO _3, CaF _2, etc. can be contained in the glass.

SrO component is a component which lowers the devitrification temperature of glass, adjusts the refractive index of glass, and is an arbitrary component in the optical glass of this invention. In particular, the devitrification resistance of glass can be improved by making content of an SrO component into 30.0% or less. Therefore, content of SrO component with respect to the glass total mass of oxide conversion composition becomes like this. Preferably it is 30.0%, More preferably, it is 20.0%, Most preferably, let 10.0% make an upper limit. SrO component is, for example, as a raw material by using _{Sr (NO 3) 2, SrF} 2 , etc. can be contained in the glass.

BaO component is a component which lowers the devitrification temperature of glass and adjusts the optical constant of glass. In particular, the devitrification resistance of glass can be improved by making content of BaO component into 30.0% or less. Therefore, content of BaO component with respect to the total glass mass of oxide conversion composition becomes like this. Preferably it is 30.0%, More preferably, it is 20.0%, Most preferably, it makes an upper limit 10.0%. BaO component, for example, as a raw material using a _{BaCO 3, Ba (NO 3)} 2 , etc. can be contained in the glass.

In the optical glass of the present invention, the RO component (wherein R is one or more selected from the group consisting of Zn, Mg, Ca, Sr, and Ba) is used to lower the devitrification temperature of the glass and adjust the refractive index as described above. Although it is a useful component, when the total content of these RO components is too much, the devitrification resistance of glass will rather deteriorate rather easily. Therefore, the total content of the RO component with respect to the total glass mass of the oxide conversion composition is preferably 30.0%, more preferably 20.0%, and most preferably 10.0%. In addition, in the optical glass of this invention, even if it does not contain RO component, it is possible to manufacture the optical glass with reduced solarization, but adjusting the optical constant of glass is made easy by making total content of RO component into 1.0% or more. You can do it. Therefore, the total content of the RO component with respect to the total glass mass of the oxide conversion composition is preferably 0.1%, more preferably 0.5%, and most preferably 1.0%.

Li ₂ O is a component decreasing the partial dispersion ratio (θg, F) of the glass and, lower the devitrification temperature of the glass, a component to decrease the glass transition point (Tg), is any component in the optical glass of the present invention. In particular, when the content of the Li ₂ O component is 20.0% or less, the solarization becomes difficult, so that the optical glass with reduced solarization can be easily obtained. Therefore, the content of Li ₂ O component to the entire mass of the glass composition in terms of oxide, and a preferably 20.0%, more preferably 15.0%, most preferably from 10.0% as an upper limit. In the optical glass of the present invention, since the total amount of do not contain Li ₂ O component is possible to produce an optical glass the solarization is reduced, but the Li ₂ O component by not less than 0.1%, a glass transition point (Tg Since)) becomes low, the glass which is easy to perform press molding can be obtained. Therefore, the total content of the Li ₂ O component with respect to the total glass mass of the oxide conversion composition is preferably 0.1%, more preferably 0.5%, and most preferably 1.0%. The Li ₂ O component can be contained in the glass using, for example, Li ₂ CO ₃ , LiNO ₃ , LiF, or the like as a raw material.

The Na ₂ O component is a component that lowers the glass transition point (Tg) and is an optional component in the optical glass of the present invention. In particular, by the content of Na ₂ O ingredient to less than 30.0%, it is possible to facilitate vitrification, since the increase of the devitrification temperature of the glass suppressed. Therefore, the content of Na ₂ O component to the entire mass of the glass composition in terms of oxide, and a preferably 30.0%, more preferably 20.0%, most preferably 15% as an upper limit. In the optical glass of the present invention, since the total amount of required free of Na ₂ O component is possible to produce an optical glass the solarization is reduced, but the Na ₂ O component by not less than 0.1%, a glass transition point (Tg Since)) becomes low, the glass which is easy to perform press molding can be obtained. Therefore, the total content of the Na ₂ O component with respect to the total glass mass of the oxide conversion composition is preferably 1.0%, more preferably 2.0%, and most preferably 3.0%. The Na ₂ O component can be contained in the glass using, for example, Na ₂ CO ₃ , NaNO ₃ , NaF, Na ₂ SiF _6, or the like.

K ₂ O component is an optional component of a component to decrease the glass transition point (Tg), the optical glass of the present invention. In particular,,, it is possible to facilitate vitrification, since the increase of the devitrification temperature of the glass by suppressing the content of K ₂ O ingredient to less than 20.0%. Therefore, it is the content of K ₂ O component to the entire mass of the glass composition in terms of oxide is preferably 20.0%, preferably 10% more, most preferably 2.0% as the upper limit. K ₂ O component is, for example, as a raw material by using a _{K 2 CO 3, KNO 3,} KF, KHF 2, K 2 SiF 6 can be contained in the glass.

In the optical glass of the present invention, Rn ₂ O component is preferably not more than 20.0%, a content by mass of the sum of (Rn in the formula is at least one member selected from the group consisting of Li, Na, K). By making this mass sum 20.0% or less, since the rise of the devitrification temperature of glass is suppressed, vitrification can be made easy. Therefore, the content by mass of the sum of Rn ₂ O component to the entire mass of the glass composition in terms of oxide, and a preferably 20.0%, more preferably 17.0%, most preferably 15% as an upper limit. In the optical glass of the present invention, since the total content of Rn ₂ does not contain the O element is possible to produce an optical glass the solarization is reduced, but Rn ₂ O component to 1.0% or more and a glass transition point (Tg Since)) becomes low, the glass which is easy to perform press molding can be obtained. Therefore, the total content of the Rn ₂ O component with respect to the total glass mass of the oxide conversion composition is preferably 1.0%, more preferably 2.0%, and most preferably 5.0%.

The La ₂ O ₃ component is a component that increases the Abbe's number of glass while increasing the refractive index of the glass, and is an optional component in the optical glass of the present invention. In particular, it is possible to increase resistance to devitrification of the glass, by the content of La ₂ O ₃ component to less than 50.0%. Therefore, the content of La ₂ O ₃ component to the entire mass of the glass composition in terms of oxide, and a preferably 50.0%, preferably 20.0% more, and most preferably from 5.0% as the upper limit. As the La ₂ O ₃ component, for example, La ₂ O ₃ , La (NO ₃ ) ₃ .XH ₂ O (where X is an arbitrary integer) and the like can be used.

Gd ₂ O ₃ component is while increasing the refractive index of the glass component to increase the Abbe number of the glass, an optional component of the optical glass of the present invention. In particular, it is possible to increase resistance to devitrification of the glass, by the content of Gd ₂ O ₃ component to less than 30.0%. Therefore, the content of Gd ₂ O ₃ component to the entire mass of the glass composition in terms of oxide, and a preferably 30.0%, preferably 10% more, and most preferably from 5.0% as the upper limit. As the Gd ₂ O ₃ component, for example, Gd ₂ O ₃ , GdF _3, or the like can be used.

Y ₂ O ₃ is a component while increasing the refractive index of the glass components to increase the resistance to devitrification of the glass, an optional component of the optical glass of the present invention. In particular, when the content of the Y ₂ O ₃ component is 30.0% or less, the increase in the liquidus temperature of the glass is suppressed, and thus, it is difficult to devitrify the glass when the glass is produced from the molten state. Therefore, the content of Y ₂ O ₃ component to the entire mass of the glass composition in terms of oxide, and a preferably 30.0%, preferably 15% more, and most preferably from 5.0% as the upper limit. Y ₂ O ₃ component, it is possible to use, for example, as a raw material Y ₂ O _3, YF ₃ and the like.

In the optical glass of the present invention, that the content by weight of the sum of Ln ₂ O ₃ component (wherein Ln is at least one member selected from the group consisting of La, Y, Gd) more than 30.0% is preferable. By making this mass sum 30.0% or less, the devitrification resistance of glass can be improved. Therefore, the content by mass of the total of Ln ₂ O ₃ component to the entire mass of the glass composition in terms of oxide, and a preferably 30.0%, preferably 15% more, and most preferably from 5.0% as the upper limit.

Ga ₂ O ₃ component is a component improving the refractive index of the glass, an optional component of the optical glass of the present invention. In particular, when the content of the Ga ₂ O ₃ component is 20.0% or less, the amount of the expensive Ga ₂ O ₃ component used is reduced, so that the material cost of the glass can be reduced. Therefore, the content of Ga ₂ O ₃ component to the entire mass of the glass composition in terms of oxide, and a preferably 20.0%, more preferably 15.0%, most preferably from 10.0% as an upper limit. The Ga ₂ O ₃ component can be contained in the glass using, for example, Ga ₂ O ₃ or the like as a raw material.

TeO ₂ is a component for raising the refractive index of the glass, a component to decrease the glass transition point (Tg), is any component in the optical glass of the present invention. In particular, when the content of the TeO ₂ component is 50.0% or less, the internal transmittance of the glass can be increased while reducing the coloring of the glass. Therefore, the content of TeO ₂ component of the glass the total mass of the oxide in terms of composition, to preferably less than 50%, as a preferably 30.0%, more preferably 15% than the upper limit, and most preferably 10.0% do. The TeO ₂ component can be contained in glass using TeO ₂ etc. as a raw material.

Bi ₂ O ₃ component is up to the refractive index of the glass, a component to decrease the glass transition point (Tg), is any component in the optical glass of the present invention. In particular, when the content of the Bi ₂ O ₃ component is 50.0% or less, the internal transmittance of the glass can be increased while reducing the coloring of the glass. Therefore, the content of Bi ₂ O ₃ component of the glass the total mass of the oxide in terms of composition, preferably 50%, more preferably 30.0%, more preferably to 15.0% as an upper limit, and most preferably from 10.0% It is less than. Bi ₂ O ₃ component is, for example, as a raw material can be contained in the glass by using a Bi ₂ O _3.

The CeO ₂ component is a component that adjusts the optical constant of the glass, improves the solarization of the glass, and is an optional component in the optical glass of the present invention. In particular, by the content of the CeO ₂ component to less than 10%, it is possible to reduce the solarization of the glass. Therefore, the content of the CeO ₂ component to the entire mass of the glass composition in terms of oxide, and a preferably 10.0%, more preferably 5.0%, most preferably from 1.0% as the upper limit. However, since the CeO ₂ component is contained, the absorption tends to occur at a specific wavelength in the visible range. Therefore, it is preferable that the CeO ₂ component is not substantially included in terms of coloring of the glass. CeO ₂ component can be contained in glass using CeO ₂ etc. as a raw material.

In addition, for fining the glass component (淸澄), and defoaming is not limited to the above-Sb ₂ O ₃ component, it is possible to use a refining agent or defoamer, or in a combination of well-known in the field of glass production.

<About components which should not be contained>

Next, the component which should not be contained in the optical glass of this invention, and the component which is not preferable to contain are demonstrated.

Other components can be added to the optical glass of this invention as needed in the range which does not impair the characteristic of glass.

However, each transition metal component such as V, Cr, Mn, Co, Ni, Cu, Ag, and Mo, except for Ti, Zr, and Nb, may be colored even in the case of containing a small amount alone or in combination with each other. Since there is a property of causing absorption at a specific wavelength of, it is particularly preferable that the optical glass using the wavelength in the visible region is not substantially included.

Further, lead compounds and As ₂ O _3, such as arsenic compounds, and the components of Th, Cd, Tl, Os, Be and Se of such as PbO is, tends to forego the use of a hazardous chemicals in recent years, the production of glass In addition to the process, measures on environmental measures are required from the processing process and the disposal after commercialization. Therefore, in the case of emphasizing environmental effects, it is preferable not to contain these substantially except inevitable mixing. As a result, the substance which contaminates the environment is not substantially contained in the optical glass. Therefore, this optical glass can be manufactured, processed, and discarded without taking special environmental measures.

The glass which is preferably used as the optical glass of the present invention is not directly expressed by mol% of the substrate because its composition is expressed in mass% relative to the total mass of glass in terms of oxide, but it is required in the present invention. The composition by mole-% display of each component which exists in the glass composition which satisfy | fills the various characteristics to become takes the following values generally by oxide conversion composition.

1.0-70.0 mol% of SiO ₂ components and

Nb ₂ O ₅ Component 3.0 ~ 25.0 mol%

And

0-50.0 mol% and / or TiO ₂ component

0-55.0 mol% and / or B ₂ O ₃ component

0-30.0 mol% and / or GeO ₂ component

0-25.0 mol% and / or Al ₂ O ₃ component

0-15.0 mol% and / or ZrO ₂ component

0 to 5.0 mole% of Ta ₂ O ₅ component and / or

WO ₁ component 0-10.0 mol% and / or

ZnO component 0-40.0 mol% and / or

MgO component 0-45.0 mol% and / or

CaO component 0-55.0 mol% and / or

SrO component 0-30.0 mol% and / or

BaO component 0-20.0 mol% and / or

0-55.0 mol% and / or Li ₂ O component

0-45.0 mol% and / or Na ₂ O component

0-20.0 mol% and / or K ₂ O component

0-25.0 mol% and / or La ₂ O ₃ component

0-10.0 mol% and / or Gd ₂ O ₃ component

Y ₂ O ₃ Component 0-15.0 mol% and / or

Ga ₂ O ₃ component 0-10.0 mol% and / or

0-30.0 mol% of TeO ₂ component and / or

0-20.0 mol% and / or Bi ₂ O ₃ component

CeO ₂ Component 0 ~ 3.0mol%

<Physical properties>

As for the optical glass of this invention, it is preferable that solarization is 5.0% or less. Thereby, the color balance becomes difficult for the apparatus which put the optical glass to worsen even by long-term use. In particular, since the higher the use temperature, the larger the solarization, the optical glass of the present invention is particularly effective when used under high temperature, such as for a vehicle. Therefore, the solarization of the optical glass of the present invention is preferably 5.0%, more preferably 4.8%, and most preferably 4.5%. In addition, in this specification, "solarization" shows the amount of deterioration of the spectral transmittance in 450 nm at the time of irradiating an ultraviolet-ray to glass, Specifically, Japan Optical Glass Industry Association JOGIS04-1994 "Solarization of optical glass Is measured by measuring the spectral transmittances before and after irradiating light of a high-pressure mercury lamp, respectively.

Moreover, the optical glass of this invention has a desired partial dispersion ratio ((theta) g, F) in the relation with Abbe's number ((nu) _d ), and can correct chromatic aberration of a lens more accurately. More specifically, the partial dispersion ratios θg and F of the optical glass of the present invention are (−1.60 × 10 ⁻³ × ν _d +0) in a range of ν _d ≦ 25 between Abbe numbers ν _d . .6346) ≤ (θg, F) ≤ (-4.21 × 10 ^-3 × v _{d +} 0.7207), satisfying the relationship, and in the range of ν _d > 25 (-2.50 × 10 ^-3 × v _d + 0 .6571) ≤ (θg, F) ≤ (-4.21 x 10 ^-3 x v _{d +} 0.7207). As a result, an optical glass having the desired partial dispersion ratio θg and F while having a low solarization can be obtained. Therefore, chromatic aberration of the lens in the optical apparatus can be corrected with high accuracy over a long period of time. Here, the partial dispersion ratio (θg, F) of the optical glass at ν _d ≦ 25 is preferably (−1.60 × 10 ⁻³ × ν _d +0.6346), and more preferably (−1.60 × 10 ^{− 3} x v _d +0.6366), and most preferably (-1.60 x ^10-3 x v _d +0.6386) as a lower limit. In addition, the partial dispersion ratios (θg, F) of the optical glass at ν _d > 25 are preferably (−2.50 × 10 ⁻³ × ν _d +0.6571), and more preferably (−2.50 × 10 ^{− 3} x v _d +0.6591), and most preferably (-2.50 x 10 ^-3 x v _{d +} 0.6611) as a lower limit. On the other hand, the upper limit of the partial dispersion ratios (θg, F) of the optical glass is preferably (−4.21 × 10 ⁻³ × ν _d +0.7207), more preferably (−4.21 × 10 ⁻³ × ν _d +0 7187), more preferably (-4.21 x ^10-3 x v _d +0.7177), most preferably (-4.21 x ^10-3 x v _d +0.7172). Moreover, especially in the area | region where Abbe's number ((nu) _d ) is small, the partial dispersion ratio ((theta) g, F of general glass exists in the value higher than normal line, and it is compared with the partial dispersion ratio ((theta) g, F) of general glass. The relationship of Abbe's number ν _d is represented by a curve. However, since the approximation of this curve is difficult, the present invention shows that the partial dispersion ratio (θg, F) is lower than that of general glass by using a straight line having different inclinations around v _d = 25.

Moreover, it is preferable that the optical glass of this invention has the glass transition point (Tg) of 400 degreeC or more and 650 degrees C or less. When glass transition point (Tg) is 400 degreeC or more, the bad influence by the frictional heat which generate | occur | produces when carrying out grinding | polishing process with respect to glass can be reduced. On the other hand, when the glass transition point (Tg) is 650 ° C. or lower, press molding at a lower temperature is possible, so that oxidation of the metal mold used for mold press molding can be reduced, thereby achieving longer life. . Therefore, glass transition point (Tg) of the optical glass of this invention becomes like this. Preferably it is 400 degreeC, More preferably, it is 450 degreeC, Most preferably, 500 degreeC is a lower limit, Preferably it is 650 degreeC, More preferably, 620 degreeC, Most preferably, 600 degreeC is an upper limit.

Moreover, it is preferable that the optical glass of this invention has a yield point (At) of 450 degreeC or more and 700 degrees C or less. The yield point At is one of the indices indicating the softness of the glass similarly to the glass transition point Tg, and is an index indicating the temperature close to the press molding temperature. Therefore, by using glass whose yield point At is 450 degreeC or more, the bad influence by the frictional heat which arises when carrying out the grinding | polishing process with respect to glass can be reduced. Moreover, since press molding at a lower temperature becomes possible by using glass whose yield point At is 700 degrees C or less, press molding can be performed more easily. Therefore, the yield point At of the optical glass of the present invention is preferably 450 ° C, more preferably 500 ° C, most preferably 540 ° C as the lower limit, preferably 700 ° C, more preferably 670 ° C, most preferably 650 ° C as the upper limit.

Moreover, it is preferable that the optical glass of this invention has predetermined refractive index and dispersion (Abe number). More specifically, the refractive index n _d of the optical glass of the present invention is preferably 1.78, more preferably 1.80, most preferably 1.82 is the lower limit, preferably 1.95, more preferably 1.92, Most preferably, 1.90 is an upper limit. In addition, the Abbe's number (ν _d ) of the optical glass of the present invention is preferably 18, more preferably 20, most preferably 22 as a lower limit, preferably 30, more preferably 28, most preferably. The upper limit is 27. As a result, the degree of freedom of optical design can be increased, and a large amount of light can be obtained even if the device is thinned.

[Method of Inhibiting Deterioration of Spectral Transmittance of Glass]

Next, the deterioration suppression method of the spectral transmittance of the glass of this invention is demonstrated. In the method for suppressing deterioration of the spectral transmittance of the present invention, the content of the Sb ₂ O ₃ component contained in the glass is reduced. Thereby, solarization of glass reduces even if it irradiates an ultraviolet-ray. For this reason, the optical glass by which time-dependent deterioration of the spectral transmittance was suppressed can be obtained easily. Here, the means for reducing the content of the Sb ₂ O ₃ component is, for example, a means for reducing the content of the Sb ₂ O ₃ component contained in the raw material, but is not limited thereto. Moreover, it is more effective if it uses together the method of reducing Pt component and Fe component.

[Production of glass and glass molding]

The glass used by the optical glass of this invention and the deterioration suppression method of the spectral transmittance of this invention is produced as follows, for example. That is, raw materials are mixed uniformly so that each component exists in the range of predetermined content. After the prepared mixture is poured into a quartz crucible and coarsely melted, it is placed in a platinum crucible or a platinum alloy crucible, melted for a predetermined time in a predetermined temperature range, homogenized by stirring, and foaming is performed. Next, the optical glass is produced by lowering the temperature of the molten glass and pouring it into a mold to cool. Here, when the material is melted using a platinum crucible, since the glass can be melted at a high temperature, glass having a high melting temperature, for example, the SiO ₂ component and the Nb ₂ O ₅ component described above, and / or TiO _Although glass containing _two components can be melted efficiently, the Pt component is easily eluted from the platinum crucible into the glass. Therefore, in order to reduce elution of the Pt component to glass, the melting temperature of the glass is preferably 1400 ° C, more preferably 1300 ° C, most preferably 1200 ° C, and the melting time of the glass is preferably It is 6 hours, More preferably, it is 4 hours, Most preferably, it is 2 hours.

From the produced optical glass, a glass molded body can be produced using means, such as reheat press molding and precision press molding, for example. That is, a lens preform for forming a mold press can be produced from optical glass, and after forming a rich press on the lens preform, polishing can be performed to produce a glass molded body. Moreover, the glass molded object can also be produced by performing precision press molding with respect to the lens preform produced by carrying out grinding | polishing process. In addition, the means for producing a glass molded body is not limited to these means.

Although the glass molded body produced in this way is useful for various optical elements, it is especially preferable to use for the use of optical elements, such as a lens and a prism. As a result, the deterioration of the spectral transmittance of the optical element with time is suppressed, so that the color balance of the optical element can be made worse even with long-term use.

Example

Compositions of Examples (No. 1 to No. 159) and Comparative Examples (No. 1 to No. 2) of the present invention, concentrations of Pt component and Fe component of these glasses, refractive index (n _d ), Abbe number ( ν _d ), the results of the spectral transmittance, solarization, partial dispersion ratio (θg, F), glass transition point (Tg), and yield point (At) at a wavelength of 450 nm before and after light irradiation are shown in Tables 1 to 22. Shown in In addition, the following Examples are for the purpose of illustration only, and are not limited only to these Examples.

The glass of the examples (No. 1 to No. 159) and the comparative examples (No. 1 to No. 2) of the present invention are all used as raw materials for the respective components, corresponding to oxides, hydroxides, carbonates, nitrates, fluorides, hydroxides, The raw material of the high purity used for normal optical glass, such as a metaphosphate compound, was selected, and it weighed and mixed uniformly so that it might become the ratio of the composition of each Example and the comparative example shown in Table 1-Table 22. Thereafter, the mixture was charged into a platinum crucible, melted for 2 to 4 hours in a temperature range of 1200 to 1350 ° C. in an electric furnace depending on the difficulty of melting the glass composition, and homogenized by stirring to remove bubbles. Thereafter, the temperature of the molten glass was lowered to 1100 to 1200 ° C, homogenized by stirring, poured into a mold, and cooled to prepare a glass.

Here, content of the Pt component and Fe component of the glass of Example (No. 1-No. 159) and the comparative example (No. 1-No. 2) makes the glass which has the composition of an Example and a comparative example into powder form, The solution obtained by treating with acid was measured using an ICP emission spectrometer (Vista-PRO manufactured by Seiko Instruments Inc.).

In addition, the solarization of the glass of an Example (No. 1-No. 159) and a comparative example (No. 1-No. 2) is Japanese Optical Glass Industry Standard JOGIS04-1994 "Method of measuring the solarization of an optical glass". According to this, the change (%) of the light transmittance at a wavelength of 450 nm before and after light irradiation was measured. Here, light irradiation was performed by heating an optical glass sample at 100 degreeC, and irradiating the light of wavelength 450nm for 4 hours using an ultrahigh pressure mercury lamp.

In addition, the refractive index (n _d ), Abbe's number (ν _d ), and partial dispersion ratio (θg, F) of the glass of Examples (No. 1 to No. 159) and Comparative Examples (No. 1 to No. 2) Was measured based on the Japan Optical Glass Industry Standard JOGIS01-2003. And when the inclination a in the relation ((theta) g, F) =-a * (nu) _d + b is 0.0016, 0.0020, and 0.00421 with respect to the value of the calculated Abbe number (v _d ) and partial dispersion ratio ((theta) g, F), The intercept b was obtained. In addition, the glass used for this measurement used the thing which processed in the slow cooling furnace using the slow cooling rate as -25 degreeC / hr.

In addition, the glass transition point (Tg) and yield point (At) of the glass of an Example (No. 1-No. 159) and a comparative example (No. 1-No. 2) are parallax heat measuring apparatus (Nechgerete) It was calculated | required by performing the measurement using Bausa made from STA-409 CD. Here, the sample particle size at the time of measuring was 425-600 micrometers, and the temperature increase rate was 10 degreeC / min.

As shown in Table 1-Table 22, all the optical glasses of the Example of this invention were 5.0% or less of solarization, More specifically, they were 4.3% or less, and were in the desired range. On the other hand, the glass of the comparative example had larger solarization than 5.0%. Therefore, compared with the glass of the comparative example, in the optical glass of the Example of this invention, it turned out that the solarization of the optical glass by long time irradiation of an ultraviolet-ray is reduced.

As for the optical glass of the Example of this invention, the thing of (nu) _{d =} 25 has the partial dispersion ratio ((theta) g, F) more than (-1.60 * 10 <^-3> v _{d +} 0.6346), More specifically, it is (-1.60 * 10 <^{->). 3} x v _{d +} 0.6497) or more. Moreover, as for v _d > 25, the partial dispersion ratios (θg, F) are (−2.50 × 10 ⁻³ × ν _d +0.6571) or more, more specifically (−2.50 × 10 ⁻³ × ν _d +0. 6670). On the other hand, the partial dispersion ratios (θg, F) of the optical glass of the embodiment of the present invention are (−4.21 × 10 ⁻³ × ν _d +0.7207) or less, more specifically (−4.21 × 10 ⁻³ × ν _d +0.7187) or less. Therefore, it turned out that these partial dispersion ratios ((theta) g, F) exist in the desired range. On the other hand, in all the glasses of the comparative example of this invention, partial dispersion ratio ((theta) g, F) exceeded (-4.21 * 10 <^-3> v ( _d ) +0.7187). Therefore, it turned out that the optical glass of the Example of this invention has a small partial dispersion ratio ((theta) g, F) in the relation with Abbe's number ((nu) _d ) compared with the glass of a comparative example.

In addition, all of the optical glasses of the embodiment of the present invention have a refractive index n _d of 1.78 or more, more specifically 1.82 or more, and the refractive index n _d is 1.95 or less, more specifically 1.90 or less, and a desired range. Was mine.

Moreover, as for the optical glass of the Example of this invention, all the Abbe's number ((nu) _d ) is 18 or more, more specifically, 22 or more, and this Abbe's number ((nu) _d ) is 30 or less, More specifically, it is 27 or less, Was in the range of.

Moreover, all of the optical glasses of the Example of this invention have a glass transition point (Tg) 400 degreeC or more, more specifically 500 degreeC or more, and this glass transition point (Tg) is 650 degreeC or less, More specifically, 600 degreeC It was below and was in a desired range.

Moreover, all the optical glasses of the Example of this invention have a yield point (At) of 450 degreeC or more, more specifically 540 degreeC or more, and this yield point (At) is 700 degrees C or less, More specifically, it is 650 degrees C or less. , Was within the scope of hope.

In addition, after performing Richt press molding using the optical glass of the Example of this invention, grinding and polishing were performed, it processed into the shape of a lens and a prism, and obtained the glass molded object. Moreover, the lens preform for precision press molding was formed using the optical glass of the Example of this invention, and this lens preform was precision press-molded and the glass molded object was obtained. As a result, the embodiment of the optical glass of the present invention, Sb ₂ O and the content of the _three components _is a predetermined amount or less, the resulting glass shaped body is less solarization, possible to have a predetermined spectral transmittance of a lens and a prism for a long period of time free A molded product was obtained. On the other hand, the comparative example is glass, and contains a predetermined or more Sb ₂ O ₃ component, the resulting glass shaped body was easily colored by ultraviolet light. For this reason, as for the glass molded object produced from the optical glass of the Example of this invention, compared with the glass molded object produced from the glass of the comparative example, solarization was reduced and it turned out that the deterioration of spectral transmittance with time is suppressed.

As mentioned above, although this invention was demonstrated in detail for the purpose of illustration, it is understood that this embodiment is only for the purpose of illustration only, and many changes can be made by a person skilled in the art without deviating from the mind and range of this invention. .

Claims (14)

With respect to the total mass of the glass composition in terms of oxide, and the content of Sb ₂ O ₃ component not more than 0.5% in mass%, solarization (deterioration amount of the spectral transmittance at a wavelength of 450nm) optical glass is not more than 5.0%. The method of claim 1,
Content of Pt component is 15 ppm or less, Optical glass characterized by the above-mentioned. The method according to claim 1 or 2,
Content of Fe component is 50 ppm or less with respect to the glass total mass of oxide conversion composition, The optical glass characterized by the above-mentioned. 4. The method according to any one of claims 1 to 3,
An optical glass containing a SiO ₂ component, an Nb ₂ O ₅ component, and / or a TiO ₂ component. The method of claim 4, wherein
Regarding the total glass mass of the oxide conversion composition, 1.0% or more and 60.0% or less of the SiO ₂ component and 10.0% or more and 65.0% or less of the Nb ₂ O ₅ component are contained in mass%, and the content of the TiO ₂ component is 40.0% or less. Characterized by optical glass. The method according to any one of claims 1 to 5,
By mass% with respect to the total glass mass of oxide conversion composition
0-20.0% of B ₂ O ₃ component, and / or
0-30.0% GeO ₂ component, and / or
0-25.0% Al ₂ O ₃ component, and / or
ZrO ₂ component 0-20.0%, and / or
Ta ₂ O ₅ component 0-20.0%, and / or
WO ₂ component 0-20.0%, and / or
ZnO component 0-30.0%, and / or
0-20.0% MgO component, and / or
CaO component 0-30.0%, and / or
0-30.0% SrO component, and / or
0-30.0% BaO component, and / or
0-20.0% Li ₂ O component, and / or
Na ₂ O component 0-30.0%, and / or
K ₂ O component 0 ~ 20.0% of the optical glass, characterized in that. The method according to any one of claims 1 to 6,
By mass% with respect to the total glass mass of oxide conversion composition
La ₂ O ₃ component 0-50.0%, and / or
0-30.0% Gd ₂ O ₃ component, and / or
Y ₂ O ₃ component 0-30.0%, and / or
0-20.0% Ga ₂ O ₃ component, and / or
0-50.0% TeO ₂ component, and / or
0-50.0% of Bi ₂ O ₃ component, and / or
CeO ₂ component 0-10.0%, The optical glass characterized by the above-mentioned. The method according to any one of claims 1 to 7,
Between the partial dispersion ratio (θg, F) with the Abbe number (ν _d), in the range of ^{_{ν d ≤25 (-1.60 × 10 -3}} × ν d +0.6346) ≤ (θg, F) ≤ (- 4.21 × 10 ⁻³ × ν _d +0.7207), satisfying the relationship, and (−2.50 × 10 ⁻³ × ν _d +0.6571) ≦ (θg, F) ≦ (−4.21 in the range of ν _d > 25. × 10 ^-3 optical glass characterized in that it satisfies the relationship × ν _d +0.7207). The method according to any one of claims 1 to 8,
The glass transition point (Tg) is 400 degreeC or more and 650 degrees C or less, The optical glass characterized by the above-mentioned. The optical element which uses the optical glass as described in any one of Claims 1-9 as a base material. The lens preform consisting of the optical glass of any one of Claims 1-9. The lens preform for mold press molding which consists of an optical glass of any one of Claims 1-9. The optical element formed by shape | molding the lens preform of Claim 11 or 12. As a method of suppressing deterioration of the spectral transmittance of glass,
How to suppress the deterioration of the spectral transmittance to reduce the content of Sb ₂ O ₃ component contained in the glass.

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