TW201827372A - Optical glass, preform, and optical element having high refractive index and high dispersion of color with low production cost - Google Patents

Abstract

The present invention provides an optical glass, a preform, and an optical element, wherein the optical glass has optical characteristics of high refractive index and high dispersion of color, and the production cost of the glass is low. The optical glass contains, in mass%, more than 0% to 45.0% of a La2O3 component, more than 0% to 45.0% of a TiO2 component, and more than 0% to 40.0% of a BaO component. The total amount of the SiO2 component and the B2O3 component is 5.0% or more and 30.0% or less, the mass ratio of TiO2/(TiO2+BaO) is 0.10 or more and 0.90 or less, the refractive index (nd) is 1.90 or more, the Abbe number ([nu]d) is 30.0 or less, and the wavelength ([lambda]5) indicating the spectral transmittance of 5% is 400 nm or less.

Description

 Optical glass, preforms, and optical components  

This invention relates to optical glass, preforms, and optical components.

In recent years, the digitization of machines using optical systems and the high definition of images and images are rapidly developing. In particular, the high definition of images and images is extremely remarkable in optical cameras such as digital cameras, video recorders, and projectors. Further, at the same time, weight reduction and miniaturization can be achieved by reducing the number of optical elements incorporated in the optical system of these optical devices, such as lenses or cymbals.

Among the optical glasses in which optical elements are produced, in particular, the demand for high refractive index high dispersion glass having a high refractive index (n _d ) of 1.90 or more and a low Abbe number (ν _d ) of 15.0 or more and 30.0 or less is high because Such an optical glass can achieve an overall weight reduction and miniaturization of the optical system. As such a high refractive index low dispersion glass, a glass composition represented by Patent Document 1 is known.

[Previous Technical Literature]

[Patent Literature]

Patent Document 1: Japanese Laid-Open Patent Publication No. 2011-178571.

However, in order to promote high refractive index and high dispersion, the glass described in Patent Document 1 has a high content of components such as a GeO ₂ component, a Nb ₂ O ₅ component, and a Ta ₂ O ₅ component, and has a high production cost. This kind of problem exists. Therefore, it is desired to have an optical glass which has not only a high refractive index/high dispersion but also a wavelength (λ ₅ ) indicating a spectral transmittance of 5% and a low production cost.

In view of the above problems, an object of the present invention is to provide an optical glass having a high refractive index and a wavelength (λ ₅ ) indicating a spectral transmittance of 5%, and having a low production cost, and a preform using the optical glass. With optical components.

In order to solve the above problems, the inventors of the present invention have focused on the results of the cumulative test and found that the total amount of the SiO ₂ component and the B ₂ O ₃ component is adjusted by using the La ₂ O ₃ component, the TiO ₂ component, and the BaO component in combination. Or the mass ratio of TiO ₂ /(TiO ₂ +BaO), the desired high refractive index and high dispersion can be obtained, and the production cost is lowered, and the wavelength (λ ₅ ) indicating that the spectral transmittance is 5% becomes short, and the completion is completed. this invention.

Specifically, the present invention provides the following.

(1) An optical glass comprising, by mass% of the oxide, more than 0% to 45.0% of the La ₂ O ₃ component, more than 0% to 45.0% of the TiO ₂ component, and more than 0% to 40.0% of the BaO component. And the total amount of the SiO ₂ component and the B ₂ O ₃ component is 5.0% or more and 30.0% or less; the mass ratio of TiO ₂ /(TiO ₂ +BaO) is 0.10 or more and 0.90 or less; and the refractive index (n _d ) is 1.90 or more. The Abbe number (ν _d ) is 30.0 or less, and the wavelength (λ ₅ ) indicating that the spectral transmittance is 5% is 400 nm or less.

(2) The optical glass according to (1), wherein the SiO ₂ component is 0% to 30.0% by mass based on the oxide, and the B ₂ O ₃ component is 0% to 30.0%.

(3) The optical glass according to (1) or (2), wherein the ZnO component is 0% to 20.0% by mass based on the oxide, and the Y ₂ O ₃ is 0% to 15.0%, Nb ₂ O _{The 5} component is 0% to 25.0%, the Yb ₂ O ₃ component is 0% to 15.0%, and the Gd ₂ O ₃ component is 0% to 15.0%.

(4) The optical glass according to any one of (1) to (3), wherein (La ₂ O ₃ + Nb ₂ O ₅ + Gd ₂ O ₃ + Yb ₂ O ₃ ) based on the mass % of the oxide The sum of the masses is greater than 0% and less than 60.0%.

(5) The optical glass according to any one of (1) to (4), wherein the Ln ₂ O ₃ component (wherein Ln is selected from the group consisting of La, Gd, Y, Yb) The total amount of one or more of the groups is greater than 0% and 50.0% or less.

(6) The optical glass according to any one of (1) to (5), wherein the mass ratio of TiO ₂ /BaO is more than 0 and 3.00 or less on the basis of the oxide.

(7) The optical glass according to any one of (1) to (6) wherein, in the mass % of the oxide, the Rn ₂ O component (wherein Rn is selected from the group consisting of Li, Na, and K) The mass sum of one or more of them is 15.0% or less.

(8) The optical glass according to any one of (1) to (7), wherein, in the mass % of the oxide, the RO component (wherein R is selected from the group consisting of Mg, Ca, Sr, Ba, and Zn) The mass sum of one or more types in the group is greater than 0% and 35.0% or less.

(9) The optical glass according to any one of (1) to (8), wherein the mass % of the oxide is 0% to 20.0% of the ZrO ₂ component, and 0% to 15.0% of the Nb ₂ O ₅ component. 0% to 10.0% of WO ₃ component, 0% to 10.0% of Ta ₂ O ₅ component, 0% to 15.0% of MgO component, 0% to 15.0% of CaO component, 0% to 15.0% of SrO component, and 0 component of Li ₂ O % to 15.0%, Na ₂ O component 0% to 15.0%, K ₂ O component 0% to 15.0%, P ₂ O ₅ component 0% to 10.0%, GeO ₂ component 0% to 10.0%, Al ₂ O ₃ component 0% to 15.0%, Ga ₂ O ₃ component 0% to 15.0%, Bi ₂ O ₃ component 0% to 10.0%, TeO ₂ component 0% to 10.0%, SnO ₂ component 0% to 3.0%, and Sb ₂ O ₃ ingredients 0% to 1.0%.

(10) A preform obtained from the optical glass of any one of (1) to (9).

(11) An optical element comprising the optical glass of any one of (1) to (9).

(12) An optical device comprising the optical element according to (11).

According to the present invention, it is possible to provide an optical glass which has not only a high refractive index but also a wavelength (λ ₅ ) indicating a spectral transmittance of 5% and a low production cost, and a preform and an optical element using the optical glass.

Fig. 1 is a schematic diagram showing a normal line represented by a rectangular coordinate with a partial dispersion ratio (θg, F) as a vertical axis and an Abbe number (ν _d ) as a horizontal axis.

2 is a schematic view showing the relationship between the partial dispersion ratio (θg, F) and the Abbe number (ν _d ) of the glass of the embodiment of the present invention.

The optical glass of the present invention contains, by mass%, more than 0% to 45.0% of the La ₂ O ₃ component, more than 0% to 45.0% of the TiO ₂ component, and more than 0% to 40.0% of the BaO component; the SiO ₂ component and the B ₂ component The total amount of the O ₃ component is 5.0% or more and 30.0% or less; the mass ratio of TiO ₂ /(TiO ₂ +BaO) is 0.10 or more and 0.90 or less; the refractive index (n _d ) is 1.90 or more, and the Abbe number (ν _d ) is 30.0 or less, and the wavelength (λ ₅ ) which shows the spectral transmittance of 5% is 400 nm or less.

According to the present invention, by adjusting the content of each component by using the La ₂ O ₃ component, the TiO ₂ component, and the BaO component in combination, high refractive index and high dispersion of the glass can be expected, and the stability of the glass can be improved. Therefore, it is possible to provide an optical glass which has a high refractive index and a high dispersion and which has a short wavelength (λ ₅ ) indicating a spectral transmittance of 5% and a low production cost, and a preform and an optical element using the optical glass.

[Glass composition]

The composition range of each component constituting the optical glass of the present invention is as follows. In the present specification, the content of each component is expressed by mass% of the total mass of the glass based on the oxide, unless otherwise specified. Here, the "oxide-based" is an oxide, a composite salt, a metal fluoride or the like which is used as a raw material of the glass component of the present invention, and when it is completely decomposed into an oxide during melting, the oxide is used. The total mass is set to 100% by mass to represent the composition of various components contained in the glass.

<About essential ingredients, optional ingredients>

The La ₂ O ₃ component is a component which increases the refractive index of the glass and reduces the dispersion. In particular, by containing La ₂ O ₃ component is greater than 0%, it is possible to obtain the desired high refractive index, as a necessary ingredient. Therefore, the content of the La ₂ O ₃ component is preferably more than 0%, more preferably 3.0%, still more preferably 15.0%, still more preferably 20.0%, still more preferably 25.0%, and still more preferably 27.0%.

On the other hand, when the content of the La ₂ O ₃ component is 45.0% or less, the devitrification resistance of the glass can be improved, the specific gravity of the glass can be suppressed from increasing, and the production cost can be reduced. Therefore, the upper limit of the content of the La ₂ O ₃ component is preferably 45.0%, preferably 40.0%, more preferably 38.0%, still more preferably 37.0%.

As the La ₂ O ₃ component, La ₂ O ₃ , La(NO ₃ ) ₃ ‧XH ₂ O (X is an arbitrary integer), or the like can be used as a raw material.

When the content of the TiO ₂ component is more than 0%, the refractive index of the glass can be increased, the Abbe number can be lowered, the partial dispersion ratio can be increased, and an essential component for devitrification resistance can be improved. Therefore, the lower limit of the content of the TiO ₂ component is preferably more than 0%, more preferably 5.0%, still more preferably 10.0%, still more preferably 15.0%, still more preferably 18.0%, and still more preferably more than 20.0. %.

On the other hand, by setting the content of the TiO ₂ component to 45.0% or less, the coloration of the glass can be reduced and the visible light transmittance can be improved. Further, it is also possible to suppress devitrification caused by the excessive TiO ₂ component. Therefore, the upper limit of the content of the TiO ₂ component is preferably 45.0%, preferably 38.0%, more preferably 32.0%, still more preferably 27.0%, and still more preferably 25.0%.

As the TiO ₂ component, TiO ₂ or the like can be used as a raw material.

When the BaO component is more than 0%, the refractive index or devitrification resistance of the glass can be increased, and an essential component of the meltability of the glass raw material can be improved. Therefore, the content of the BaO component is preferably more than 0%, more preferably 5.0%, still more preferably 8.0%, still more preferably 10.0%.

On the other hand, by setting the content of the BaO component to 40.0% or less, it is difficult to lower the refractive index of the glass, and the devitrification of the glass can be reduced. Therefore, the upper limit of the content of the BaO component is preferably 40.0%, more preferably 35.0%, still more preferably 28.0%, still more preferably 23.0%, still more preferably 20.0%.

As the BaO component, BaCO ₃ , Ba(NO ₃ ) ₂ or the like can be used as a raw material.

The sum (mass sum) of the content of the B ₂ O ₃ component and the SiO ₂ component is preferably 5.0% or more and 30.0% or less.

In particular, by setting the sum to 5.0% or more, deterioration of devitrification resistance due to deficiency of the B ₂ O ₃ component or the SiO ₂ component can be suppressed. Therefore, the lower limit of the mass and (B ₂ O ₃ + SiO ₂ ) is preferably 5.0%, preferably 7.0%, more preferably 9.0%.

On the other hand, by setting the sum to 30.0% or less, it is possible to suppress a decrease in the refractive index due to the excessive inclusion of the components, so that a desired high refractive index can be easily obtained. Therefore, the upper limit of the mass and (B ₂ O ₃ + SiO ₂ ) is preferably 30.0%, preferably 23.0%, more preferably 18.0%, and still more preferably 16.50%.

In this case, the content of the _second component and the content of the component BaO and TiO ₂ and TiO component ratio (mass ratio), preferably to 0.10 or more. Thereby, in addition to maintaining a high refractive index and high dispersion, a high partial dispersion ratio can be obtained. Therefore, the mass ratio of TiO ₂ /(TiO ₂ +BaO) has a lower limit of preferably 0.10, preferably 0.30, more preferably 0.40, and still more preferably 0.45.

On the other hand, by setting the mass ratio to 0.90 or less, the coloration of the glass can be reduced, the visible light transmittance can be improved, and devitrification can be suppressed. Therefore, the mass ratio of TiO ₂ /(TiO ₂ +BaO) has an upper limit of preferably 0.90, preferably 0.80, more preferably 0.73, still more preferably 0.68.

When the content of the SiO ₂ component is more than 0%, an optional component which is resistant to devitrification can be improved. Therefore, the lower limit of the content of the SiO ₂ component is preferably more than 0%, more preferably more than 0.5%, still more preferably more than 1.0%, and still more preferably more than 2.0%.

On the other hand, by setting the content of the SiO ₂ component to 30.0% or less, the SiO ₂ component can be easily melted in the molten glass, and the melting can be prevented at a high temperature. The content of the SiO ₂ component is preferably 30.0%, more preferably 23.0%, still more preferably 16.0%, still more preferably 11.0%, still more preferably 9.0%.

As the SiO ₂ component, SiO ₂ , K ₂ SiF ₆ , Na ₂ SiF ₆ or the like can be used as a raw material.

When the content of the B ₂ O ₃ component is more than 0%, a network structure can be formed in the glass to promote the formation of a stable glass, and an optional component which is resistant to devitrification can be improved. Therefore, the lower limit of the content of the B ₂ O ₃ component is preferably more than 0%, more preferably more than 0.5%, still more preferably more than 1.0%, and still more preferably more than 2.0%.

On the other hand, when the content of the B ₂ O ₃ component is 30.0% or less, the decrease in the refractive index can be suppressed, the Abbe number can be made small, and the deterioration of chemical durability can be suppressed. Therefore, the upper limit of the content of the B ₂ O ₃ component is preferably 30.0% or less, more preferably 20.0%, still more preferably less than 15.0%, still more preferably 12.0%, still more preferably less than 10.0%.

As the B ₂ O ₃ component, H ₃ BO ₃ , Na ₂ B ₄ O ₇ , Na ₂ B ₄ O ₇ ‧10H ₂ O, BPO ₄ or the like can be used as a raw material.

When the content of the ZnO component is more than 0%, the meltability of the glass can be improved, the glass transition point can be lowered, and any component devitrified can be reduced. Therefore, the lower limit of the content of the ZnO component is preferably more than 0%, more preferably more than 0.5%, still more preferably more than 1.0%, and still more preferably more than 1.5%.

On the other hand, by setting the content of the ZnO component to 20.0% or less, the refractive index can be lowered or devitrified. Further, since the viscosity of the molten glass can be improved by this, the occurrence of streaking of the glass can be reduced. Therefore, the upper limit of the content of the ZnO component is preferably 20.0%, preferably 15.0%, more preferably 11.0%, still more preferably 8.0%.

As the ZnO component, ZnO, ZnF ₂ or the like can be used as a raw material.

When the content of the Y ₂ O ₃ component is more than 0%, an arbitrary component which can suppress an increase in the material cost of the glass can be suppressed.

By setting the content of the Y ₂ O ₃ component to 15.0% or less, it is possible to suppress the decrease in the refractive index of the glass, to reduce the Abbe number, and to improve the devitrification resistance of the glass. Therefore, the upper limit of the content of the Y ₂ O ₃ component is preferably 15.0%, preferably 10.0%, more preferably 5.0%.

As the Y ₂ O ₃ component, Y ₂ O ₃ , YF ₃ or the like can be used as a raw material.

When the content of the Nb ₂ O ₅ component is more than 0%, the refractive index of the glass can be increased, and an optional component which is resistant to devitrification can be improved. Therefore, the content of the Nb ₂ O ₅ component is preferably more than 0%, more preferably 2.0%, still more preferably 4.0%.

On the other hand, by setting the content of the Nb ₂ O ₅ component to 25.0% or less, it is possible to suppress the deterioration of the glass devitrification resistance due to the excessive Nb ₂ O ₅ or to suppress the low transmittance of visible light. And can suppress the increase in the material cost of the glass. Therefore, the upper limit of the content of the Nb ₂ O ₅ component is preferably 25.0%, preferably 20.0%, more preferably 16.0%, still more preferably 13.0%.

As the Nb ₂ O ₅ component, Nb ₂ O ₅ or the like can be used as a raw material.

When the content of the Yb ₂ O ₃ component is more than 0%, an arbitrary component of the refractive index of the glass can be increased.

On the other hand, by setting the content of the Yb ₂ O ₃ component to 15.0% or less, the devitrification resistance of the glass can be improved, and the Abbe number can be made small. Thus, Yb ₂ O ₃ content of the composition, preferably the upper limit to 15.0%, preferably 10.0%, more preferably 5.0%.

As the Yb ₂ O ₃ component, Yb ₂ O ₃ or the like can be used as a raw material.

When the content of the Gd ₂ O ₃ component is more than 0%, the refractive index of the glass can be increased, and an arbitrary component of the Abbe number can be increased.

On the other hand, by reducing the particularly expensive Gd ₂ O ₃ component of the rare earth element to 15.0% or less, the material cost of the glass can be reduced, so that an optical glass having a lower cost can be produced. In addition, the Abbe number of the glass can be prevented from rising to more than necessary. Therefore, the upper limit of the content of the Gd ₂ O ₃ component is preferably 15.0%, preferably 10.0%, more preferably 5.0%.

As the Gd ₂ O ₃ component, Gd ₂ O ₃ , GdF ₃ or the like can be used as a raw material.

Further, in the optical glass of the present invention, the sum (mass sum) of the contents of the La ₂ O ₃ component, the Nb ₂ O ₅ component, the Gd ₂ O ₃ component, and the Yb ₂ O ₃ component is preferably 60.0% or less. Thereby, since the content of these high-priced components can be reduced, the material cost of glass can be suppressed, and the Abbe number can be made small. Therefore, the upper limit of the mass and (La ₂ O ₃ + Nb ₂ O ₅ + Gd ₂ O ₃ + Yb ₂ O ₃ ) is preferably 60.0%, preferably 57.0%, more preferably 53.0%, and still more preferably 49.0%, and even more preferably 47.0%.

On the other hand, the desired high refractive index can be obtained by containing a mass sum of the components greater than 0%. Therefore, the lower limit is preferably more than 0%, preferably 10.0%, more preferably 20.0%, still more preferably 25.0%, still more preferably 30.0%, and still more preferably 35.0%.

The sum (mass sum) of the content of the Ln ₂ O ₃ component (wherein Ln is one or more selected from the group consisting of La, Gd, Y, and Yb) is preferably from 0% to 50%.

In particular, by setting the mass sum to be greater than 0%, the refractive index of the glass can be increased, so that a glass having a high refractive index can be easily obtained. In addition, the color of the glass can be reduced by this. Therefore, the lower limit of the content of the Ln ₂ O ₃ component is preferably more than 0%, more preferably 1.0%, still more preferably 3.0%, still more preferably 5.0%.

On the other hand, by setting the mass sum to 50.0% or less, the devitrification resistance can be improved and the Abbe number can be made small. Therefore, the upper limit of the content of the Ln ₂ O ₃ component is preferably 50.0%, preferably less than 40.0%, more preferably 30.0%, still more preferably 25.0%.

Here, the ratio (mass ratio) of the content of the TiO ₂ component to the sum of the contents of the La ₂ O ₃ component, the Nb ₂ O ₅ component, the Gd ₂ O ₃ component, and the Yb ₂ O ₃ component is preferably greater than 0. Thereby, in addition to maintaining high refractive index and high dispersion, a high partial dispersion ratio can be obtained, and production cost can be made low. Therefore, the mass ratio TiO ₂ /(La ₂ O ₃ +Nb ₂ O ₅ +Gd ₂ O ₃ +Yb ₂ O ₃ ) has a lower limit of more than 0, preferably 0.10, more preferably 0.20, and thus more preferably Is 0.40.

On the other hand, by setting the mass ratio to 2.00 or less, the coloration of the glass can be reduced, the visible light transmittance can be improved, and devitrification can be suppressed. Therefore, the mass ratio of TiO ₂ /(La ₂ O ₃ +Nb ₂ O ₅ +Gd ₂ O ₃ +Yb ₂ O ₃ ) has an upper limit of 2.00, preferably 1.00, more preferably 0.80, and still more preferably 0.66.

Here, the ratio (mass ratio) of the content of the TiO ₂ component to the content of the BaO component is preferably greater than zero. Thereby, in addition to maintaining a high refractive index and high dispersion, a high partial dispersion ratio can be obtained. The mass ratio TiO ₂ /BaO has a lower limit of more than 0, preferably 0.10, more preferably 0.40, and still more preferably 0.60.

On the other hand, by setting the mass ratio to 3.00 or less, the coloring of the glass can be reduced, the visible light transmittance can be improved, and devitrification can be suppressed. Therefore, the mass ratio of TiO ₂ /BaO has an upper limit of 3.00, preferably 2.00, more preferably 1.60.

Here, the ratio of the sum of the content of the TiO ₂ component to the content of the WO ₃ component to the BaO component (mass ratio) is preferably greater than zero. Thereby, in addition to maintaining high refractive index and high dispersion, a high partial dispersion ratio can be obtained, and devitrification resistance can be improved. Therefore, the mass ratio (TiO ₂ + WO ₃ ) / BaO has a lower limit of more than 0, preferably 0.30, more preferably 0.60, still more preferably 0.80, still more preferably 1.00.

On the other hand, by setting the mass ratio to 3.00 or less, the coloring of the glass can be reduced, the visible light transmittance can be improved, and devitrification can be suppressed. Therefore, the mass ratio (TiO ₂ + WO ₃ ) / BaO has an upper limit of 3.00, preferably 2.50, more preferably 1.90.

The sum (mass sum) of the content of the TiO ₂ component and the Nb ₂ O ₅ component is preferably greater than 0%. Thereby, the refractive index/dispersion of the glass can be improved, and the devitrification resistance can be improved. Therefore, the mass and (TiO ₂ + Nb ₂ O ₅ ) have a lower limit of more than 0%, preferably more than 10.0%, more preferably more than 15.0%, still more preferably more than 20.0%, and still more preferably More than 25.0%.

On the other hand, by setting the mass sum to 60.0% or less, the coloration of the glass can be reduced, the visible light transmittance can be improved, and devitrification can be suppressed. Therefore, the upper limit of the mass and (TiO ₂ + Nb ₂ O ₅ ) is preferably 60.0%, preferably less than 50.0%, more preferably 45.0%, still more preferably 40.0%, and still more preferably 35.0%. Further preferably, it is 33.0%.

The total amount of the Rn ₂ O component (wherein Rn is one or more selected from the group consisting of Li, Na, K, and Cs) is preferably 15.0% or less. Thereby, it is possible to suppress the decrease in the refractive index of the glass and to improve the devitrification resistance. Therefore, the upper limit of the mass of the Rn ₂ O component is preferably 15.0%, preferably 10.0%, more preferably less than 5.0%, still more preferably less than 1.0%.

The sum (mass sum) of the content of the RO component (wherein R is one or more selected from the group consisting of Mg, Ca, Sr, and Ba) is preferably 35.0% or less. Thereby, devitrification caused by the excessive RO component can be reduced, and the refractive index can be suppressed from being lowered. Therefore, the upper limit of the content of the RO component is preferably 35.0%, more preferably 30.0%, still more preferably 27.0%, still more preferably less than 23.0%, and still more preferably 20.0%.

On the other hand, by setting the mass sum to more than 0%, the meltability of the glass raw material or the stability of the glass can be improved. Therefore, the lower limit of the total content of the RO component is preferably more than 0%, more preferably 4.0%, still more preferably 7.0%, still more preferably more than 9.0%.

When the content of the ZrO ₂ component is more than 0%, it contributes to a high refractive index and a low dispersion of the glass, and an optional component which can improve the devitrification resistance of the glass. Therefore, the lower limit of the content of the ZrO ₂ component is preferably more than 0%, preferably 0.5%, more preferably 1.0%.

On the other hand, by setting the ZrO ₂ component to 20.0% or less, it is possible to suppress the deterioration of the glass devitrification resistance or the Abbe number due to the excessive ZrO ₂ component. Therefore, the upper limit of the content of the ZrO ₂ component is preferably 20.0%, preferably 16.0%, more preferably 12.0%, still more preferably 9.0%, and still more preferably less than 6.5%.

As the ZrO ₂ component, ZrO ₂ , ZrF ₄ or the like can be used as a raw material.

When the content of the WO ₃ component is more than 0%, in addition to reducing the coloration of the glass due to other high refractive index components, the refractive index can be increased, the partial dispersion ratio can be increased, and the devitrification resistance of the glass can be improved. Any ingredient. Further, the WO ₃ component is also a component capable of lowering the glass transition point. Therefore, the lower limit of the content of the WO ₃ component is preferably more than 0%, preferably 0.1%, more preferably 0.2%, still more preferably 0.3%.

On the other hand, by setting the content of the WO ₃ component to 10.0% or less, the glass coloration by the WO ₃ component can be reduced, and the visible light transmittance can be improved. Therefore, the upper limit of the content of the WO ₃ component is preferably 10.0%, preferably 5.0%, more preferably 3.0%.

As the WO ₃ component, WO ₃ or the like can be used as a raw material.

When the content of the Ta ₂ O ₅ component is more than 0%, the refractive index of the glass can be increased, and an optional component which is resistant to devitrification can be improved.

On the other hand, by lowering the expensive Ta ₂ O ₅ component to 10.0% or less, the material cost of the glass can be reduced, so that an optical glass having a lower cost can be produced. In addition, by setting the content of the Ta ₂ O ₅ component to 10.0% or less, the melting temperature of the raw material can be lowered, and the energy required for melting the raw material can be reduced, so that the production cost of the optical glass can also be reduced. Therefore, the upper limit of the content of the Ta ₂ O ₅ component is preferably 10.0%, preferably 8.0%, more preferably 5.0%. In particular, from the viewpoint of producing an optical glass having a lower cost, the content of the Ta ₂ O ₅ component is preferably 4.0%, more preferably 3.0%, still more preferably less than 1.0%, and most preferably no. contain.

As the Ta ₂ O ₅ component, Ta ₂ O ₅ or the like can be used as a raw material.

When the content of the MgO component is more than 0%, the meltability of the glass raw material or the devitrification resistance of the glass can be increased.

On the other hand, by setting the content of the MgO component to 15.0% or less, it is possible to suppress a decrease in refractive index or a decrease in devitrification resistance due to the excessive inclusion of such components. Therefore, the upper limit of the content of the MgO component is preferably 15.0%, preferably 10.0%, more preferably 5.0%.

As the MgO component, MgCO ₃ , MgF ₂ or the like can be used as a raw material.

When the content of the CaO component is more than 0%, the refractive index or the devitrification resistance of the glass can be increased, and an optional component which can improve the meltability of the glass raw material can be obtained. Therefore, the content of the CaO component is preferably more than 0%, more preferably 0.5%, still more preferably 1.5%, still more preferably 3.0%.

On the other hand, by setting the content of the CaO component to 15.0% or less, it is difficult to lower the refractive index of the glass, and the devitrification of the glass can be reduced. Therefore, the upper limit of the content of the CaO component is preferably 15.0%, preferably 10.0%, more preferably 5.0%.

As the CaO component, CaCO ₃ , CaF ₂ or the like can be used as a raw material.

When the content of the SrO component is more than 0%, the refractive index or the devitrification resistance of the glass can be increased, and any component which can improve the meltability of the glass raw material can be obtained. Therefore, the lower limit of the content of the SrO component is preferably more than 0%, more preferably 0.5%, still more preferably 1.5%, still more preferably 3.0%.

On the other hand, by setting the content of the SrO component to 15.0% or less, it is difficult to lower the refractive index of the glass, and the devitrification of the glass can be reduced. Therefore, the upper limit of the content of the SrO component is preferably 15.0%, preferably 10.0%, more preferably 5.0%.

As the SrO component, SrCO ₃ or SrF ₂ can be used as a raw material.

When the Li ₂ O component, the Na ₂ O component, and the K ₂ O component are at least 0% of the content of at least one of them, the component can improve the meltability of the glass. In particular, the K ₂ O component is also a component capable of further increasing the partial dispersion ratio of the glass.

On the other hand, by reducing the content of the Li ₂ O component, the Na ₂ O component, or the K ₂ O component, the refractive index of the glass can be suppressed from being lowered, and devitrification can be reduced. In particular, by reducing the content of the Li ₂ O component, it is possible to suppress a partial dispersion ratio of the glass from being lowered. Therefore, the content of at least one of the Li ₂ O component, the Na ₂ O component and the K ₂ O component is preferably 15.0% or less, more preferably less than 10.0%, still more preferably less than 5.0%, and furthermore Good is less than 1.0%.

As the Li ₂ O component, the Na ₂ O component, and the K ₂ O component, Li ₂ CO ₃ , LiNO ₃ , LiF, Na ₂ CO ₃ , NaNO ₃ , NaF, Na ₂ SiF ₆ , K ₂ CO ₃ , KNO ₃ , or the like can be used. KF, KHF ₂ , K ₂ SiF ₆ and the like are used as raw materials.

When the content of the P ₂ O ₅ component is more than 0%, the component which is resistant to devitrification of the glass can be improved. In particular, by setting the content of the P ₂ O ₅ component to 10.0% or less, it is possible to suppress the deterioration of the chemical durability of the glass, in particular, the deterioration of the water resistance. Therefore, the upper limit of the content of the P ₂ O ₅ component is preferably 10.0%, preferably 5.0%, more preferably 3.0%.

As the P ₂ O ₅ component, Al(PO ₃ ) ₃ , Ca(PO ₃ ) ₂ , Ba(PO ₃ ) ₂ , BPO ₄ , H ₃ PO ₄ or the like can be used as a raw material.

When the content of the GeO ₂ component is more than 0%, the refractive index of the glass can be increased, and an optional component which is resistant to devitrification can be improved. However, since the raw material of GeO ₂ is expensive, if the usage amount is high, the material cost becomes high, and the cost reduction effect by reducing the Gd ₂ O ₃ component or the Ta ₂ O ₅ component is impaired. Therefore, the content of the GeO ₂ component is preferably 10.0%, more preferably 5.0%, still more preferably 1.0%, and most preferably no.

As the GeO ₂ component, GeO ₂ or the like can be used as a raw material.

When the content of the Al ₂ O ₃ component and the Ga ₂ O ₃ component is more than 0%, the chemical durability of the glass can be improved, and an optional component which is resistant to devitrification of the glass can be improved.

On the other hand, by setting the content of the Al ₂ O ₃ component and the Ga ₂ O ₃ component to 15.0% or less, it is possible to suppress the deterioration of the glass devitrification resistance due to the excessive content of the components. Therefore, the upper limit of the content of each of the Al ₂ O ₃ component and the Ga ₂ O ₃ component is preferably 15.0%, more preferably 8.0%, still more preferably 3.0%.

As the raw material of the Al ₂ O ₃ component and the Ga ₂ O ₃ component, Al ₂ O ₃ , Al(OH) ₃ , AlF ₃ , Ga ₂ O ₃ , Ga(OH) ₃ or the like can be used.

When the content of the Bi ₂ O ₃ component is more than 0%, the refractive index can be increased, and any component of the glass transition point can be lowered.

On the other hand, by setting the content of the Bi ₂ O ₃ component to 10.0% or less, the devitrification resistance of the glass can be improved, and the coloration of the glass can be reduced to improve the visible light transmittance. Therefore, the upper limit of the content of the Bi ₂ O ₃ component is preferably 10.0%, preferably 5.0%, more preferably 3.0%.

As the Bi ₂ O ₃ component, Bi ₂ O ₃ or the like can be used as a raw material.

When the content of the TeO ₂ component is more than 0%, the refractive index can be increased, and any component of the glass transition point can be lowered.

However, when the glass raw material is placed in a crucible made of platinum or the portion placed in contact with the molten glass is melted in a molten bath formed of platinum, there is a problem that the TeO ₂ component may be alloyed with platinum. Therefore, the upper limit of the content of the TeO ₂ component is preferably 10.0%, preferably 5.0%, more preferably 3.0%, and even more preferably no.

As the TeO ₂ component, TeO ₂ or the like can be used as a raw material.

When the content of the SnO ₂ component is more than 0%, the molten glass can be oxidized to make the molten glass clear, and it is difficult to deteriorate the light transmittance of the glass.

On the other hand, when the content of the SnO ₂ component is 3.0% or less, coloring of the glass due to reduction of the molten glass or devitrification of the glass is less likely to occur. Further, since the alloying of the SnO ₂ component with the melting device (particularly, a noble metal such as Pt) is reduced, it is expected that the life of the melting device is prolonged. Therefore, the content of the SnO ₂ component is preferably 3.0% or less, more preferably less than 2.0%, still more preferably less than 1.0%, and even more preferably no.

As the SnO ₂ component, SnO, SnO ₂ , SnF ₂ , SnF ₄ or the like can be used as a raw material.

The Sb ₂ O ₃ component is an optional component capable of defoaming the molten glass when the content thereof is more than 0%.

On the other hand, by setting the content of the Sb ₂ O ₃ component to 1.0% or less, excessive foaming is less likely to occur, and alloying with a melting device (particularly, a noble metal such as Pt) is reduced. Therefore, the content of the Sb ₂ O ₃ component is preferably 1.0% or less, preferably less than 0.5%, more preferably less than 0.3%, still more preferably less than 0.1%.

As the Sb ₂ O ₃ component, Sb ₂ O ₃ , Sb ₂ O ₅ , Na ₂ H ₂ Sb ₂ O ₇ ‧5H ₂ O or the like can be used as a raw material.

Further, the component which clarifies and defoams the glass is not limited to the above-mentioned Sb ₂ O ₃ component, and a clarifier, an antifoaming agent or a combination thereof which is well known in the field of glass production can be used.

When the content of the F component is more than 0%, the Abbe number of the glass can be increased, the glass transition point can be lowered, and an optional component which is resistant to devitrification can be improved.

However, the content of the F component, that is, the total amount of F which is a fluoride which replaces part or all of one or two or more kinds of oxides of the above-mentioned respective metal elements, is more than 10.0%, and the amount of volatilization of the F component is changed. There are many, so it becomes difficult to obtain a stable optical constant, and it is difficult to obtain a homogeneous glass. In addition, the Abbe number will rise to more than necessary.

Therefore, the content of the component F is preferably 10.0% or less, more preferably less than 5.0%, still more preferably less than 3.0%, still more preferably less than 1.0%, and still more preferably not contained.

<About ingredients that should not be included>

Next, the components which should not be contained in the optical glass of the present invention and the components which are not suitable for inclusion will be described.

In the optical glass of the present invention, other components may be added as needed within a range that does not affect the characteristics of the glass of the present invention. However, the GeO ₂ component causes the dispersion of the glass to be improved, and it is preferably not contained.

In addition, various transition metal components other than Ti, Zr, Nb, W, La, Gd, Y, Yb, and Lu, such as Hf, V, Cr, Mn, Fe, Co, Ni, Cu, Ag, Mo, Ce, Nd When it is contained in a single or composite form, even if it contains a small amount of light which will color the glass and absorb light of a specific wavelength in the visible light region, it is especially in the optical glass using the wavelength of the visible light region. It is not really preferable to contain it.

In addition, lead compounds such as PbO and arsenic compounds such as As ₂ O ₃ and components of Th, Cd, Tl, Os, Be, and Se have been regarded as harmful chemical substances in recent years, and there is a tendency to avoid use, not only In the manufacturing steps of glass, even in the processing steps and after the product is processed, it is necessary to deal with environmental countermeasures. Therefore, in the case where the influence of the environment is emphasized, it is preferable that the components are not substantially contained in addition to the inevitable mixing. Thereby, the optical glass can be made substantially free of substances that pollute the environment. Therefore, the optical glass can be manufactured, processed, and discarded without taking special environmental measures.

[Production method]

The optical glass of the present invention can be produced, for example, in the following manner. That is, the raw materials are uniformly mixed in a predetermined content range, and the produced mixture is placed in a platinum crucible, a quartz crucible or an aluminoxane to be initially melted, and then the platinum and platinum are placed. In a crucible, a platinum alloy crucible, or a crucible, it is melted in a temperature range of 900 ° C to 1400 ° C for 1 hour to 5 hours, stirred to homogenize and defoamed, and then cooled to 1300 ° C or lower, followed by cooling to 1300 ° C or lower. The final stage of stirring is carried out to remove the streaks, and then formed by molding using a molding die. Here, as a method of obtaining the glass formed by using a molding die, a method of drawing the molten glass into the molding die, pulling the drawn glass from the other end of the molding die, or casting the molten glass may be mentioned. In the mold, let it cool down.

[physical property]

The optical glass of the present invention preferably has a high refractive index and a high dispersion.

In particular, the refractive index (n _d ) of the optical glass of the present invention has a lower limit of 1.90, preferably 1.95, more preferably 1.98. The upper limit of the refractive index is preferably 2.20, preferably 2.15 or less, more preferably less than 2.10.

Further, the Abbe number (ν _d ) of the optical glass of the present invention has a lower limit of preferably 15.0, preferably 18.0 or more, more preferably 20.0 or more, and the upper limit is preferably 30.0 or less, preferably 28.0 or less. More preferably, it is 27.0.

By having such a high refractive index, a large amount of refraction can be obtained even if the optical element is desired to be thinned. Further, by having such a high dispersion, high imaging characteristics can be achieved when combined with, for example, an optical element having a low dispersion (high Abbe number).

Therefore, the optical glass of the present invention can exert an effect on optical design, and in particular, in addition to high imaging characteristics and the like, it is possible to achieve miniaturization of the optical system and increase the degree of freedom in optical design.

The optical glass of the present invention preferably has a high visible light transmittance, and particularly has a high light transmittance in terms of short wavelength in visible light, whereby coloring is less.

In particular, the optical glass of the present invention, when expressed by the transmittance of glass, represents a wavelength (λ ₇₀ ) having a spectral transmittance of 70% in a sample having a thickness of 10 mm, and the upper limit is preferably 500 nm, more preferably 490 nm, more preferably 480 nm.

Further, in the optical glass of the present invention, the shortest wavelength (λ ₅ ) of the spectral transmittance of 5% is shown in the sample having a thickness of 10 mm, and the upper limit is preferably 400 nm, preferably 390 nm.

Thereby, the absorption edge of the glass becomes in the vicinity of the ultraviolet light region, and the transparency of the glass to visible light can be improved, and therefore, the optical glass can be applied to an optical element such as a lens that penetrates light.

The optical glass of the present invention preferably has a high partial dispersion ratio (θg, F). More specifically, the partial dispersion ratio (θg, F) of the optical glass of the present invention has a lower limit of preferably 0.570, preferably 0.580, more preferably 0.595, still more preferably 0.605, still more preferably 0.612.

Further, the partial dispersion ratio (θg, F) of the optical glass of the present invention, which is related to the Abbe number (ν _d ), preferably corresponds to (-0.00162 ν _d + 0.645) ≦ (θg, F) ≦ (- 0.00162ν _d +0.680) relationship.

Thereby, an optical glass having a small partial dispersion ratio (θg, F) can be obtained, and the optical glass can function to reduce chromatic aberration of the optical element and the like.

Therefore, the partial dispersion ratio (θg, F) of the optical glass of the present invention has a lower limit of (-0.00162 ν _d + 0.645), preferably (-0.00162 ν _d + 0.650). On the other hand, the partial dispersion ratio (θg, F) of the optical glass of the present invention has an upper limit of (-0.00162 ν _d + 0.675), preferably (-0.00162 ν _d + 0.670).

The relationship between the partial dispersion ratio (θg, F) and the Abbe number (ν _d ) is a straight line in which the partial dispersion ratio is the vertical axis and the Abbe number is the horizontal axis, and a straight line parallel to the normal line is used. To represent. The normal line indicates the linear relationship observed between the partial dispersion ratio (θg, F) and the Abbe number (ν _d ) of the conventionally known glass, and the partial dispersion ratio (θg, F) is used as the vertical axis. The Abbe number (ν _d ) is a rectangular coordinate of the horizontal axis and is represented by a straight line connecting the partial dispersion ratio of the mark NSL7 and PBM2 and the two points of the Abbe number (refer to Fig. 1). Further, the relationship between the partial dispersion ratio of the conventionally known glass and the Abbe number is substantially the same as the normal.

Here, NSL7 and PBM2 are optical glasses made by Ohara, the Abbe number (ν _d ) of PBM2 is 36.3, the partial dispersion ratio (θg, F) is 0.5828, and the Abbe number (ν _d ) of NSL7 is 60.5. The dispersion ratio (θg, F) is 0.5436.

[Preforms and optical components]

The glass molded body can be produced from the produced optical glass by, for example, a method of polishing or a method of press molding such as re-press molding or precision press molding. In other words, the glass molded body can be produced by performing mechanical processing such as grinding and polishing on the optical glass to produce a glass molded body, and performing reheating and press molding on the preform made of optical glass. The glass molded body is produced by processing, and the preform which is produced by the polishing process or the preform which is formed by a known floating molding or the like is subjected to precision press molding to produce a glass molded body or the like. However, the method of producing the glass molded body is not limited to the above.

As described above, the glass molded body formed of the optical glass of the present invention can exhibit various functions in various optical elements and optical designs, and is particularly suitable for use in optical elements such as lenses and iridium. By improving the stability of the glass, a glass molded body having a large diameter can be formed. Therefore, in addition to the increase in size of the optical element, it is possible to achieve high definition and high precision when used in an optical device such as a camera or a projector. Imaging characteristics and projection characteristics.

[Examples]

The glass composition of the examples (No. 1 to No. 52) of the present invention, the refractive index (n _d ), the Abbe number (ν _d ), the transmittance (λ ₅ , λ ₇₀ ), and the portions of the glasses The values of the dispersion ratio (θg, F) are shown in Tables 1 to 10. Further, the following examples are for illustrative purposes only, and the invention is not limited to the embodiments.

The glass of the examples, the raw materials of the respective components, are selected from the high-purity raw materials used for general optical glass such as oxides, hydroxides, carbonates, nitrates, fluorides, hydroxides, and bismuth-acid compounds. Then, the raw materials are weighed and uniformly mixed, and then placed in a platinum crucible, and the temperature is set to an electric furnace in the range of 1280 ° C to 1340 ° C, and the melting of the glass raw material is carried out for 2.5 hours, and the molten glass is stirred. After the raw material was defoamed, the temperature was lowered to 1,180 ° C and 1,250 ° C, and the mixture was further stirred and homogenized, and then cast in a mold, and then slowly cooled to prepare a glass.

The refractive index (n _d ) and the Abbe number (ν _d ) of the glass of the examples are shown as measured values with respect to the d-line (587.56 nm) of the xenon lamp. Further, the Abbe number (ν _d ) is a refractive index using the above d line, a refractive index (n _F ) with respect to the F line (486.13 nm) of the hydrogen lamp, and a refractive index with respect to the C line (656.27 nm) ( The value of n _C ) is calculated from the equation of Abbe number (ν _d )=[(n _d -1)/(n _F -n _C )].

The partial dispersion ratio is measured by the refractive index n _{C in the C} line (wavelength 656.27 nm), the refractive index n _{F in the F} line (wavelength 486.13 nm), and the refractive index n _g in the g line (wavelength 435.835 nm). The partial dispersion ratio is calculated from the equation of (θg, F) = (n _{g -} n _F ) / (n _{F -} n _C ).

The transmittance of the glass of the examples was measured in accordance with the Japanese Optical Glass Industry Association specification JOGIS02-2003. Further, in the present invention, the presence or absence of coloration of the glass and the degree of coloration thereof are determined by measuring the transmittance of the glass. Specifically, an abrasive product having a thickness of 10 ± 0.1 mm and relatively parallel is used, and a spectral transmittance of 200 nm to 800 nm is measured according to JIS Z8722, and λ ₅ (wavelength at a transmittance of 5%) and λ _{70 are obtained.} (wavelength at a transmittance of 70%).

Further, the glass used in the measurement was treated in a slow cooling furnace using a slow cooling rate of -25 ° C / hr.

As shown in the table, the optical glass of the embodiment of the present invention has a refractive index (n _d ) of 1.90 or more, and the refractive index (n _d ) is also 2.20 or less, and more specifically 2.10 or less. All are within the desired range.

Further, in the optical glass of the embodiment of the present invention, the Abbe number (ν _d ) is 30.0 or less, more specifically 28.0 or less, and the Abbe number (ν _d ) is also 15.0 or more. Specifically, it is 20.0 or more, and it is all within a desired range.

Further, in the optical glass of the embodiment of the invention, λ ₇₀ (wavelength at a transmittance of 70%) is 500 nm or less, and more specifically 490 nm or less. Further, in the optical glass of the embodiment of the present invention, λ ₅ (wavelength at a transmittance of 5%) is 400 nm or less, and more specifically 390 nm or less.

Further, in the optical glass of the embodiment of the present invention, the partial dispersion ratio (θg, F) is (-0.00162 ν _d + 0.645) or more, and more specifically (-0.00162 ν _d + 0.650) or more.

In contrast, the partial dispersion ratio of the optical glass of the embodiment of the present invention is (-0.00162 ν _d + 0.680) or less, and more specifically (-0.00162 ν _d + 0.670) or less. Therefore, it is understood that the partial dispersion ratios (θg, F) are within a desired range.

Therefore, it is clear that the optical glass of the embodiment of the present invention can be produced at a low cost in addition to the refractive index and the Abbe number within a desired range, and the coloring can be reduced.

Further, the optical glass obtained in the examples of the present invention was subjected to grinding and polishing after reheat press forming, and processed into a shape of a lens and a crucible. Further, the optical glass of the embodiment of the present invention is used to form a preform for precision press molding, and the preform for precision press molding is precisely press-formed. In any case, the glass which is softened by heating does not cause problems such as opacification and devitrification, and can be stably processed into various lenses and crucible shapes.

The present invention has been described in detail above by way of examples, and the embodiments of the present invention are intended to be illustrative only, and those of ordinary skill in the art should understand, without departing from the scope and scope of the invention. Many modifications are possible in the present invention.

Claims (12)

An optical glass containing, by mass% of oxide, containing: a La ₂ O ₃ component greater than 0% to 45.0%; a TiO ₂ component greater than 0% to 45.0%; and a BaO component greater than 0% to 40.0%; and containing SiO The total amount of the _two components and the B ₂ O ₃ component is 5.0% or more and 30.0% or less; the mass ratio of TiO ₂ /(TiO ₂ +BaO) is 0.10 or more and 0.90 or less; the refractive index (n _d ) is 1.90 or more, and the Abbe number (ν _d ) is 30.0 or less, and the wavelength (λ ₅ ) indicating that the spectral transmittance is 5% is 400 nm or less. The optical glass according to claim 1, wherein the SiO ₂ component is 0% to 30.0% by mass based on the oxide, and the B ₂ O ₃ component is 0% to 30.0%. The optical glass according to claim 1 or 2, wherein the ZnO component is 0% to 20.0% by mass based on the oxide; the Y ₂ O ₃ is 0% to 15.0%; and the Nb ₂ O ₅ component is 0%. To 25.0%; Yb ₂ O ₃ component is 0% to 15.0%; and Gd ₂ O ₃ component is 0% to 15.0%. The optical glass according to claim 1 or 2, wherein the mass sum of (La ₂ O ₃ + Nb ₂ O ₅ + Gd ₂ O ₃ + Yb ₂ O ₃ ) is greater than 0% by mass based on the oxide. And 60.0% or less. The optical glass according to claim 1 or 2, wherein the Ln ₂ O ₃ component is represented by mass% of the oxide (wherein Ln is one selected from the group consisting of La, Gd, Y, and Yb). The total amount of the above) is more than 0% and 50.0% or less. The optical glass according to claim 1 or 2, wherein the mass ratio of TiO ₂ /BaO is more than 0 and 3.00 or less on the basis of the oxide. The optical glass according to claim 1 or 2, wherein the Rn ₂ O component (wherein Rn is one or more selected from the group consisting of Li, Na, and K) is based on the mass% of the oxide. The mass sum is 15.0% or less.  The optical glass according to claim 1 or 2, wherein the RO component is (in the formula, R is one or more selected from the group consisting of Mg, Ca, Sr, Ba, and Zn). The mass sum is greater than 0% and less than 35.0%.   The optical glass according to claim 1 or 2, wherein, based on the mass % of the oxide, it contains: 0% to 20.0% of the ZrO ₂ component; 0% to 10.0% of the WO ₃ component; and 0% of the Ta ₂ O ₅ component To 10.0%; 0% to 15.0% of MgO component; 0% to 15.0% of CaO component; 0% to 15.0% of SrO component; 0% to 15.0% of Li ₂ O component; 0% to 15.0% of Na ₂ O component; K ₂ O composition 0% to 15.0%; P ₂ O ₅ component 0% to 10.0%; GeO ₂ component 0% to 10.0%; Al ₂ O ₃ component 0% to 15.0%; Ga ₂ O ₃ component 0% to 15.0%; The Bi ₂ O ₃ component is 0% to 10.0%; the TeO ₂ component is 0% to 10.0%; the SnO ₂ component is 0% to 3.0%; and the Sb ₂ O ₃ component is 0% to 1.0%.  A preform formed of the optical glass described in claim 1 or 2.    An optical element comprising the optical glass described in claim 1 or 2.    An optical machine having the optical component of claim 11.