WO2019069553A1

WO2019069553A1 - Optical glass, preform, and optical element

Info

Publication number: WO2019069553A1
Application number: PCT/JP2018/029362
Authority: WO
Inventors: 岩▲崎▼菜那
Original assignee: 株式会社オハラ
Priority date: 2017-10-02
Filing date: 2018-08-06
Publication date: 2019-04-11
Also published as: JP7126341B2; JP2019064876A; CN111183122B; CN111183122A

Abstract

Provided is an optical glass which has a low partial dispersion ratio (θg, F) while having a refractive index (nd) and an Abbe number (νd) in a desired range. This optical glass comprises, in mass%, 15.0 to 45.0% of a SiO2 component, 10.0 to 40.0% of a Nb2O5 component, over 0 to 20.0% of a Na2O component, 5.0 to 20.0% of a mass sum (ZrO2+Li2O), and 0.90 or less of a mass ratio (BaO/MgO+CaO+SrO+BaO), wherein the partial dispersion ratio (θ g, F) satisfies the relationship (-0.00162×νd+0.620)≤(θg, F)≤(-0.00162×νd+0.657) with the Abbe number (νd), and the temperature coefficient (40 to 60°C) of the relative refractive index (589.29 nm) is in a range of +6.0×10-6 to -5.0×10-6(°C-1).

Description

Optical glass, preform and optical element

The present invention relates to an optical glass and an optical element.

Optical systems such as digital cameras and video cameras include blurs called aberrations, though the size is large. Although this aberration is classified into monochromatic aberration and chromatic aberration, in particular, the chromatic aberration strongly depends on the material properties of the lens used in the optical system.

In general, the chromatic aberration is corrected by combining a low dispersion convex lens and a high dispersion concave lens, but this combination can only correct the aberration of the red region and the green region, and the aberration of the blue region remains. The aberration in the blue region that can not be eliminated is called a secondary spectrum. In order to correct the secondary spectrum, it is necessary to carry out optical design in which the trend of g-line (435. 835 nm) in the blue region is taken into consideration. At this time, the partial dispersion ratio (θg, F) is used as an index of optical characteristics to be focused on in optical design. In an optical system combining the above-described low dispersion lens and high dispersion lens, an optical material having a large partial dispersion ratio (θg, F) is used for the low dispersion lens, and the partial dispersion ratio ( By using an optical material with a small θg, F), the secondary spectrum is well corrected.

The partial dispersion ratio (θg, F) is expressed by the following equation (1).
θ _g , F = (n _g -n _F ) / (n _F -n _C ) (1)

In optical glass, there is an approximately linear relationship between a partial dispersion ratio (θg, F) representing partial dispersion in a short wavelength range and an Abbe number (ν _d ). The straight line representing this relationship was obtained by plotting the partial dispersion ratio and Abbe number of NSL7 and PBM2 on Cartesian coordinates with partial dispersion ratio (θg, F) on the vertical axis and Abbe number (ν _d ) on the horizontal axis. It is represented by a straight line connecting two points and is called a normal line (see FIG. 1). Normal glass, which is the standard of the normal line, varies depending on the optical glass manufacturer, but they are defined by almost the same inclination and intercept. (NSL7 and PBM2 are optical glasses manufactured by OHARA INC., And the Abbe number (ν _d ) of PBM 2 is 36.3, the partial dispersion ratio (θg, F) is 0.5828, and the Abbe number (ν _d ) of NSL 7 Is 60.5, and the partial dispersion ratio (θg, F) is 0.5436.)

In recent years, a glass having an Abbe number (v _d ) of 30 or more and 45 or less is often used as an optical material having a small partial dispersion ratio (θg, F) according to needs in optical design.

Also, in recent years, optical elements incorporated in in-vehicle optical devices such as in-vehicle cameras, and optical elements incorporated in optical devices that generate a large amount of heat such as projectors, copiers, laser printers and broadcasting equipment, etc. Use in high temperature environments is increasing. In such a high temperature environment, the temperature at the time of use of the optical element constituting the optical system tends to fluctuate greatly, and the temperature often reaches 100 ° C. or more. At this time, since the adverse effect on the imaging characteristics and the like of the optical system due to the temperature fluctuation is so large that it can not be ignored, it is required to configure an optical system in which the imaging characteristics and the like are hardly affected even by the temperature fluctuation.

When constructing an optical system in which the influence of temperature fluctuations on the imaging characteristics and the like does not easily occur, the optical element is made of glass in which the refractive index decreases when the temperature rises and the temperature coefficient of the relative refractive index becomes negative. The use of an optical element made of glass in which the refractive index increases when the temperature rises and the temperature coefficient of the relative refractive index is positive corrects the influence of the temperature change on the imaging characteristics, etc. It is preferable at the point which can be done.

On the other hand, in an optical material having a small partial dispersion ratio (θg, F), a component (eg, Nb ₂ O ₅ component, La ₂ O ₃ component, etc.) contained to obtain various excellent optical properties, Due to the low content of alkali metal, the temperature coefficient of the relative refractive index tends to increase. As such optical glass, the glass compositions shown in Patent Documents 1 and 2 are known.
Furthermore, since it is often used under various environments such as in-vehicle lenses and interchangeable lenses used in recent years, optical glass with a small partial dispersion ratio (θg, F) and a small temperature coefficient of relative refractive index It has been demanded.

JP, 2013-245140, A Showa 58-125637

However, the glass disclosed in Patent Document 1 has a large content of the BaO component that increases the partial dispersion ratio, and a small content of the Nb ₂ O ₅ component that decreases the partial dispersion ratio, so the partial dispersion ratio increases. It is not sufficient for use as a lens for correcting the secondary spectrum. In addition, since the transmittance in visible light is deteriorated, it can not be said that sufficient optical characteristics are obtained. Further, the glass disclosed in Patent Document 2 has a large content of the La ₂ O ₃ component, but the content of the Nb ₂ O ₅ is small, so the partial dispersion ratio becomes large, and the content of the alkali metal is small. It can not be said that the temperature coefficient of the relative refractive index is small.

The present invention has been made in view of the above problems, and the object of the present invention is to obtain a partial dispersion ratio (n _d ) and an Abbe number (v _d ) within a desired range. An object of the present invention is to obtain an optical glass having a small θg, F) and a small temperature coefficient of relative refractive index.

The inventors of the present invention conducted intensive studies to solve the above problems, and as a result, in the glass containing the SiO ₂ component and the Nb ₂ O ₅ component, the Na ₂ O component is contained in the desired range. It has been found that an optical glass having a high refractive index, an Abbe number (high dispersion), a low partial dispersion ratio, and a small temperature coefficient of relative refractive index can be obtained, and the present invention has been completed.

(1) mass%,
SiO ₂ component 15.0 to 45.0%
Nb ₂ O ₅ component 10.0 to 40.0%
Na ₂ O ingredient more than 0 ~ 20.0%
5.0 to 20.0% by mass (ZrO ₂ + Li ₂ O),
Containing a mass ratio (BaO / MgO + CaO + SrO + BaO) of 0.90 or less,
The partial dispersion ratio (θg, F) is between the Abbe number (ν _d ),
The temperature coefficient (40 to 100) of the relative refractive index (589.29 nm) is satisfied, which satisfies the relationship of (−0.00162 × ν _d +0.620) ≦ (θg, F) ≦ (−0.00162 × ν _d + 0.657) Optical glass having a temperature of 60 ° C. in the range of + 6.0 × 10 ⁻⁶ to −5.0 × 10 ⁻⁶ (° C. ⁻¹ ).

(2) The optical glass according to (1), which has a mass ratio (Li ₂ O / Li ₂ O + Na ₂ O + K ₂ O) of 1.00 or less.

(3) Refractive index _{(n d)} and Abbe number ([nu _d) is, - satisfies the relation of _{(0.01 × ν d +2.01) ≦} n d ≦ (-0.01 × ν d +2.12) Optical glass as described in (1) or (2).

(4) A preform material comprising the optical glass according to any one of (1) to (3).

(5) An optical element comprising the optical glass according to any one of (1) to (3).

(6) An optical apparatus comprising the optical element according to (5).

According to the present invention, the refractive index (n _d) and Abbe number ([nu _d) is while remaining within the desired range, has a low partial dispersion ratio, and the temperature coefficient of the relative refractive index to obtain a small optical glass Can.

FIG. 7 is a diagram showing a normal line in which the partial dispersion ratio (θg, F) is represented on the vertical axis and the Abbe number (部分_d ) is represented on the rectangular coordinate of the horizontal axis. It is a figure which shows the relationship of the partial dispersion ratio ((theta) g, F) and Abbe's number ((nu) _d ) about the Example of this application. It is a figure which shows the refractive index ( _nd ) and Abbe's number ((nu) _d ) relationship about the Example of this application.

The optical glass of the present invention contains 15.0 to 45.0% of the SiO ₂ component, 10.0 to 40.0% of the Nb ₂ O ₅ component, and 0 of the Na ₂ O component in mass% of the oxide conversion composition. containing ultra-20.0%, the partial dispersion ratio ([theta] g, F) is between the Abbe number _{(ν d), (- 0.00162} × ν d +0.620) ≦ (θg, F) ≦ ( It is characterized in that the temperature coefficient of the relative refractive index is small, which satisfies the relationship of −0.00162 × が_d +0.657).
An optical glass containing a predetermined amount of SiO ₂ component and Nb ₂ O ₅ component and containing Na ₂ O, a glass having high refractive index and Abbe number (high dispersion) within a desired range, and low partial dispersion ratio In particular, by containing Na ₂ O in excess of 0% to 20.0%, the temperature coefficient of relative refractive index can be reduced while keeping the partial dispersion ratio (θg, F) small.
Therefore, while having desired high refractive index (n _d ) and low Abbe number ( _{d d} ), the partial dispersion ratio (θg, F) is small, which is useful for reducing the chromatic aberration of the optical system, and the relative refractive index An optical glass having a small temperature coefficient of

Hereinafter, although the embodiment of the optical glass of the present invention will be described in detail, the present invention is not limited to the following embodiment at all, and can be implemented with appropriate modifications within the scope of the object of the present invention . In addition, about the location which description overlaps, description may be abbreviate | omitted suitably, but the meaning of invention is not limited.

[Glass composition]
The composition range of each component which comprises the optical glass of this invention is described below. In the present specification, unless otherwise specified, the contents of the respective components are all represented by mass% relative to the total mass of the glass in the oxide conversion composition. Here, “oxide conversion composition” is assumed that all oxides, composite salts, metal fluorides, etc. used as raw materials of the glass component of the present invention are decomposed at the time of melting and converted into oxides, It is the composition which described each ingredient contained in glass on the basis of 100 mass% of gross mass of the generated oxide concerned.

<Required Component, Optional Component>
The SiO ₂ component promotes stable glass formation and can lower the liquidus temperature, and thus is an essential component to reduce devitrification (the generation of crystals) which is undesirable as optical glass.
In particular, by setting the content of the SiO ₂ component to 15.0% or more, a glass excellent in devitrification resistance can be obtained without significantly increasing the partial dispersion ratio. In addition, devitrification and coloring can be reduced. Therefore, the content of the SiO ₂ component is preferably 15.0% or more, more preferably 18.0% or more, more preferably 20.0% or more, and still more preferably 25.0% or more.
On the other hand, by making the content of the SiO ₂ component 45.0% or less, it is possible to easily obtain a desired high refractive index by making the refractive index difficult to reduce, and it is possible to suppress an increase in the partial dispersion ratio. Further, this can suppress the decrease in the meltability of the glass material. Therefore, the content of the SiO ₂ component is preferably 45.0% or less, more preferably 43.0% or less, still more preferably 41.5% or less, and most preferably 40.0% or less.
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.

The Nb ₂ O ₅ component is an essential component capable of enhancing the refractive index, reducing the Abbe number and the partial dispersion ratio, and enhancing the devitrification resistance.
In particular, by making the content of the Nb ₂ O ₅ component 10.0% or more, the refractive index is increased to the target optical constant and the anomalous dispersion is reduced by adjusting within the component of the range of the present invention can do. Therefore, the content of the Nb ₂ O ₅ component is preferably 10.0% or more, more preferably 12.0% or more, and still more preferably 15.0% or more.
On the other hand, by the content of _Nb 2 _{O 5} component below 40.0%, thereby reducing the material cost of the glass. In addition, it is possible to suppress the rise of the melting temperature at the time of glass production, and to reduce the devitrification due to the excessive content of the Nb ₂ O ₅ component. Furthermore, the deterioration of the chemical durability of the glass can also be improved. Therefore, the content of the Nb ₂ O ₅ component is preferably 40.0%, more preferably 38.0% or less, and further preferably 35.0% or less.
For the Nb ₂ O ₅ component, Nb ₂ O ₅ or the like can be used as a raw material.

The TiO ₂ component is an optional component that raises the refractive index, lowers the Abbe number, and increases the devitrification resistance when it is contained in excess of 0%. Therefore, the content of the TiO ₂ component is preferably more than 0%, more preferably more than 1.0%, and still more preferably 2.5%.
On the other hand, when the content exceeds 20.0%, the partial dispersion ratio is a component that increases. Therefore, by setting the content of the TiO ₂ component to 20.0% or less, the coloration of the glass can be reduced and the internal transmittance can be enhanced. Moreover, since it becomes difficult to raise a partial dispersion ratio by this, it can be easy to obtain the desired low partial dispersion ratio near a normal line. Therefore, the content of the TiO ₂ component is preferably 20.0% or less, more preferably 15.0% or less, more preferably 12.0% or less, and further preferably less than 10.0%.
TiO ₂ component can be used such as TiO ₂ as a raw material.

The K ₂ O component is an arbitrary component that increases the thermal expansion coefficient and decreases the temperature coefficient of the relative refractive index.
Therefore, the content of the K ₂ O component is preferably more than 0%, more preferably more than 0.3%, and still more preferably more than 0.5%.
On the other hand, by setting the content of the K ₂ O component to 10.0% or less, an increase in partial dispersion ratio can be suppressed, and devitrification can be reduced. Therefore, the content of the K ₂ O component is preferably 10.0% or less, more preferably less than 8.0%, and still more preferably less than 5.0%.
K ₂ O component, _K 2 _CO 3 as a raw _material, KNO _{3, _KF,} can be used KHF _2, K ₂ SiF ₆ and the like.

When the B ₂ O ₃ content is more than 0%, it promotes stable glass formation and can lower the liquidus temperature, so that the devitrification resistance can be enhanced and the meltability of the glass material can be enhanced. It is an optional component. Therefore, the content of the B ₂ O ₃ component is preferably more than 0%, more preferably more than 0.5%, more preferably more than 1.0%, still more preferably more than 1.5%. .
On the other hand, by setting the content of the B ₂ O ₃ component to 15.0% or less, the decrease in the refractive index can be suppressed and the increase in the partial dispersion ratio can be suppressed. Furthermore, the deterioration of the chemical durability of the glass can be improved. Therefore, the content of the B ₂ O ₃ component is preferably 15.0% or less, more preferably 14.0% or less, and still more preferably 12.0% or less.
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.

The Li ₂ O component is an optional component which can lower the partial dispersion ratio, improve the transmittance, lower the liquidus temperature, and enhance the meltability of the glass material, when it is contained in excess of 0%. Therefore, the content of the Li ₂ O component is preferably more than 0%, more preferably more than 0.5%, more preferably more than 1.0%, and still more preferably more than 1.5%.
On the other hand, by making the content of the Li ₂ O component 15.0% or less, the decrease in refractive index can be suppressed, and the devitrification due to the excessive content can be reduced.
Therefore, the content of the Li ₂ O component is preferably 15.0% or less, more preferably 10.0% or less, and even more preferably less than 8.0%.
As the Li ₂ O component, Li ₂ CO ₃ , LiNO ₃ , LiF or the like can be used as a raw material.

The Na ₂ O component is an optional component that can lower the partial dispersion ratio, increase the thermal expansion coefficient, and decrease the temperature coefficient of the relative refractive index, when it is contained in excess of 0%. Therefore, the content of the Na ₂ O component is preferably more than 0%, more preferably more than 0.5%, and still more preferably more than 1.0%.
On the other hand, by setting the content of the Na ₂ O component to 20.0% or less, the decrease in refractive index can be suppressed, and the devitrification due to excessive inclusion can be reduced.
Therefore, the content of the Na ₂ O component is preferably 20.0% or less, more preferably 19.0% or less, and further preferably less than 18.0%.
As the Na ₂ O component, Na ₂ CO ₃ , NaNO ₃ , NaF, Na ₂ SiF ₆ or the like can be used as a raw material.

The temperature coefficient of the relative refractive index when the sum (mass sum) of the content of the Rn ₂ O component (wherein Rn is one or more selected from the group consisting of Li, Na and K) is greater than 0 Is an optional component that can reduce Therefore, the sum of Rn ₂ O components is preferably at least 0%, more preferably at least 3.0%, and still more preferably at least 5.0%.
On the other hand, by setting the sum of the content of the Rn ₂ O component to 30.0% or less, the viscosity in the glass can be hardened to improve the formability. Accordingly, the upper limit is preferably 30.0% or less, more preferably 28.0% or less, and still more preferably 26.0% or less.

The ZrO ₂ component is an optional component capable of enhancing the refractive index and Abbe number of the glass, lowering the partial dispersion ratio, and enhancing the devitrification resistance, when it is contained in excess of 0%. In addition, devitrification and coloring can be reduced. Therefore, the lower limit of the content of the ZrO ₂ component is preferably at least 0%, more preferably at least 1.0%, and more preferably at least 3.0%.
On the other hand, when the content of the ZrO ₂ component is 10.0% or less, the devitrification can be reduced and a more homogeneous glass can be easily obtained. Therefore, the content of the ZrO ₂ component is preferably 10.0% or less, more preferably 9.0% or less, and more preferably 8.5% or less.
As the ZrO ₂ component, ZrO ₂ , ZrF ₄ or the like can be used as a raw material.

The MgO component is an optional component that can lower the melting temperature of the glass when it contains more than 0%.
On the other hand, when the content of the MgO component is 10.0% or less, the devitrification can be reduced while suppressing the decrease in the refractive index. Therefore, the content of the MgO component is preferably 10.0% or less, more preferably less than 5.0%, and still more preferably less than 3.0%.
As the MgO component, MgO, MgCO ₃ , MgF ₂ or the like can be used as a raw material.

The CaO component is an optional component capable of reducing Abbe's number, reducing devitrification and improving the meltability of the glass material while reducing the material cost of the glass when the CaO content is more than 0%. Therefore, the content of the CaO component is preferably more than 0%, more preferably more than 0.3%, and still more preferably more than 0.5%.
On the other hand, by setting the content of the CaO component to 10.0% or less, it is possible to suppress the decrease in refractive index, the increase in Abbe number, and the increase in partial dispersion ratio, and the devitrification can be reduced. Therefore, the upper limit of the content of the CaO component is preferably 10.0% or less, more preferably less than 8.0%, and still more preferably less than 6.0%. The CaO component is CaCO ₃ , CaF ₂ or the like as a raw material Can be used.

The SrO component is an optional component capable of enhancing the refractive index and enhancing the devitrification resistance, when it is contained in excess of 0%.
In particular, by setting the content of the SrO component to 10.0% or less, the deterioration of the chemical durability can be suppressed. Therefore, the content of the SrO component is preferably 10.0% or less, more preferably less than 8.0%, still more preferably less than 6.0%, and still more preferably less than 5.0%.
As the SrO component, Sr (NO ₃ ) ₂ , SrF ₂ or the like can be used as a raw material.

The BaO component is an optional component that can increase the refractive index, increase the devitrification resistance, increase the thermal expansion coefficient, and decrease the temperature coefficient of the relative refractive index when the BaO component is contained more than 0%. Therefore, the content of the BaO component is preferably more than 0%, more preferably more than 0.3%, and still more preferably more than 0.5%.
In particular, by setting the content of the BaO component to 10.0% or less, the decrease in refractive index, the increase in Abbe number, and the increase in partial dispersion ratio can be suppressed, and the devitrification can be reduced. Therefore, the content of the BaO component is preferably 10.0% or less, more preferably less than 9.0%, more preferably less than 8.5%, and still more preferably less than 8.0%.
As the BaO component, BaCO ₃ , Ba (NO ₃ ) ₂ or the like can be used as a raw material.

The ZnO component is an optional component which is inexpensive, can improve the devitrification resistance, and can lower the glass transition point, when it is contained at more than 0%. Therefore, the content of the ZnO component may be preferably more than 0%, more preferably more than 0.3%, and still more preferably more than 0.5%.
On the other hand, devitrification and coloring can be reduced by setting the content of the ZnO component to 10.0% or less. Therefore, the content of the ZnO component is preferably 10.0% or less, more preferably 8.0% or less, and more preferably less than 5.5%.

The refractive index can be increased and the partial dispersion ratio can be decreased by containing at least one of La ₂ O ₃ component, Gd ₂ O ₃ component, Y ₂ O ₃ component and Yb ₂ O ₃ component by more than 0%. It is an ingredient.
In particular, by setting the content of each of the La ₂ O ₃ component, the Gd ₂ O ₃ component, the Y ₂ O ₃ component, and the Yb ₂ O ₃ component to 10.0% or less, the increase in Abbe number can be suppressed, and the loss occurs. The permeability can be reduced and the material cost can be reduced. Therefore, the content of each of the La ₂ O ₃ component, the Gd ₂ O ₃ component, the Y ₂ O ₃ component and the Yb ₂ O ₃ component is preferably 10.0% or less, more preferably 8.0% or less, and further preferably Preferably, the upper limit is less than 7.0%.
The La ₂ O ₃ component, the Gd ₂ O ₃ component, the Y ₂ O ₃ component and the Yb ₂ O ₃ component are, as raw materials, La ₂ O ₃ , La (NO ₃ ) ₃ .XH ₂ O (where X is any integer), Y ₂ O ₃ , YF ₃ , Gd ₂ O ₃ , GdF ₃ , Yb ₂ O ₃ or the like can be used.

The Ta ₂ O ₅ component is an optional component capable of enhancing the refractive index, lowering the Abbe number and the partial dispersion ratio, and enhancing the devitrification resistance, when the Ta ₂ O ₅ component is contained.
On the other hand, by setting the content of the Ta ₂ O ₅ component to 10.0% or less, the amount of use of the Ta ₂ O ₅ component, which is a rare mineral resource, is reduced, and the glass is easily melted at a lower temperature. The production cost of glass can be reduced. This also can reduce the devitrification of the glass due to excessive content of Ta ₂ O ₅ component. Therefore, the content of the Ta ₂ O ₅ component is preferably 10.0% or less, more preferably less than 5.0%, still more preferably less than 3.0%, and still more preferably less than 1.0%. . In particular, in view of reducing the material cost of glass, the Ta ₂ O ₅ component may not be contained.
As the Ta ₂ O ₅ component, Ta ₂ O ₅ or the like can be used as a raw material.

The WO ₃ component is an optional component capable of enhancing the refractive index to lower the Abbe number, enhancing the devitrification resistance, and enhancing the meltability of the glass material, when the WO ₃ component is contained.
On the other hand, by setting the content of the WO ₃ component to 10.0% or less, the partial dispersion ratio of the glass can be hardly increased, and the coloration of the glass can be reduced to increase the internal transmittance. Therefore, the content of the WO ₃ component is preferably 10.0% or less, more preferably less than 5.0%, still more preferably less than 3.0%, and still more preferably less than 1.0%.
WO ₃ components, it is possible to use WO ₃ or the like as a raw material.

The P ₂ O ₅ component is an optional component that can enhance the stability of the glass when it contains more than 0%.
On the other hand, when the content of the P ₂ O ₅ component is 10.0% or less, devitrification due to the excessive content of the P ₂ O ₅ component can be reduced. Therefore, the content of the P ₂ O ₅ component is preferably 10.0% or less, more preferably less than 5.0%, and still more preferably less than 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 and the} like can be used as raw materials.

The GeO ₂ component is an optional component that can increase the refractive index and reduce the devitrification when it contains more than 0%.
On the other hand, by setting the content of the GeO ₂ component to 10.0% or less, the amount of use 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 is preferably 10.0% or less, more preferably less than 5.0%, and still more preferably less than 3.0%.
The GeO ₂ component can use GeO ₂ etc. as a raw material.

The Al ₂ O ₃ component and the Ga ₂ O ₃ component are optional components that can increase the refractive index and improve the devitrification resistance when containing at least either of them in excess of 0%.
On the other hand, by the respective content of the _Al 2 _{O 3} component and _Ga 2 _{O 3} component to 10.0% or less, reduce the devitrification due to excessive content of _Al 2 _{O 3} component and the _Ga 2 _{O 3} component it can. Therefore, the content of each of the Al ₂ O ₃ component and the Ga ₂ O ₃ component is preferably 10.0% or less, more preferably less than 5.0%, and still more preferably less than 3.0%.
As 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 as raw materials.

The Bi ₂ O ₃ component is an optional component which can increase the refractive index to lower the Abbe number and lower the glass transition point, when the content is more than 0%.
On the other hand, by setting the content of the Bi ₂ O ₃ component to 10.0% or less, it is possible to make it difficult to increase the partial dispersion ratio, and it is possible to reduce the coloration of the glass and to increase the internal transmittance. Therefore, the content of the Bi ₂ O ₃ component is preferably 10.0% or less, more preferably less than 5.0%, still more preferably less than 3.0%, and still more preferably less than 1.0%.
Bi ₂ O ₃ component can be used _Bi 2 _{O 3} and the like as raw materials.

The TeO ₂ component is an optional component that can increase the refractive index, lower the partial dispersion ratio, and lower the glass transition point, when it is contained in excess of 0%.
On the other hand, by setting the content of the TeO ₂ component to 5.0% or less, it is possible to reduce the coloration of the glass and to increase the internal transmittance. In addition, by reducing the use of the expensive TeO ₂ component, it is possible to obtain glass with lower material cost. Therefore, the content of the TeO ₂ component is preferably 5.0% or less, more preferably less than 3.0%, and still more preferably less than 1.0%.
As the TeO ₂ component, TeO ₂ or the like can be used as a raw material.

The SnO ₂ component is an optional component capable of clarifying (defoaming) the melted glass when it contains more than 0%, and increasing the visible light transmittance of the glass.
On the other hand, by setting the content of the SnO ₂ component to 1.0% or less, it is possible to make it difficult to cause coloring of the glass due to reduction of the molten glass and devitrification of the glass. Moreover, since the alloying of the SnO ₂ component and the melting facility (in particular, noble metals such as Pt) is reduced, the lifetime of the melting facility can be extended. Therefore, the content of the SnO ₂ component is preferably 1.0% or less, more preferably less than 0.5%, and still more preferably less than 0.1%.
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 promotes degassing of the glass when it contains more than 0%, and is a component to clarify the glass, and is an optional component in the optical glass of the present invention. The content of the Sb ₂ O ₃ component with respect to the total mass of the glass can be made to be 1.0% or less, thereby making it difficult to cause excessive foaming at the time of melting the glass, and the Sb ₂ O ₃ component is a melting facility (especially Pt Etc. can be difficult to be alloyed. Accordingly, the upper limit of the content of the Sb ₂ O ₃ component to the total glass mass of the oxide conversion composition is preferably 1.0% or less, more preferably 0.8% or less, and still more preferably 0.6% or less. .
Sb ₂ O ₃ component can be used _{_{_{_{Sb 2 O 3, Sb 2 O}}}} 5, Na 2 H 2 Sb 2 O 7 · 5 H 2 O and the like as raw materials.

The components for clarifying and degassing the glass are not limited to the above-mentioned Sb ₂ O ₃ components, and known clarifiers and defoamers in the field of glass production can be used, or a combination thereof. .

The mass sum of ZrO ₂ and Li ₂ O is preferably 5.0% or more. Thereby, glass with a small partial dispersion ratio can be obtained. Accordingly, the lower limit of the mass sum (ZrO ₂ + Li ₂ O) is 5.0% or more, more preferably 7.0% or more, and still more preferably 8.0% or more.
On the other hand, the sum of mass (ZrO ₂ + Li ₂ O) is preferably 20.0% or less. Thereby, the devitrification by excess content can be reduced and the devitrification at the time of reheat press can be suppressed. Therefore, the content is preferably 20.0% or less, more preferably 18.0% or less, and further preferably 16.0% or less.

The mass sum of ZrO ₂ and Nb ₂ O ₅ is preferably 18.0% or more. Thereby, it is possible to obtain a glass having a small partial dispersion ratio and a good transmittance. Accordingly, the lower limit of the mass sum ZrO ₂ + Nb ₂ O ₅ is preferably 18.0% or more, more preferably 19.0% or more, and still more preferably 21.1% or more.
On the other hand, the mass sum _ZrO 2 + _Nb 2 _{O 5} is preferably 45.0% or less. Thereby, the devitrification by excess content can be reduced and the devitrification at the time of reheat press can be suppressed. Therefore, the content is preferably 45.0% or less, more preferably 44.0% or less, more preferably 43.0% or less, and still more preferably 42.0% or less.

When the ratio of BaO to the mass sum of MgO, CaO, SrO and BaO is more than 0, the desired refractive index and dispersion can be obtained. Therefore, the mass ratio BaO / (MgO + CaO + SrO + BaO) is preferably more than 0, more preferably 0.05 or more, and still more preferably 0.09 or more.
On the other hand, the mass ratio BaO / (MgO + CaO + SrO + BaO) is preferably 0.90 or less. Thereby, it is possible to obtain a glass having a small partial dispersion ratio and a low specific gravity.
Therefore, it is preferably 0.90 or less, more preferably 0.85 or less, and still more preferably 0.80 or less.

The ratio of Li ₂ O to the mass sum of Li ₂ O, Na ₂ O and K ₂ O is preferably 0.01 or more. Thereby, glass with a small partial dispersion ratio can be obtained. Therefore, the mass ratio Li ₂ O / (Li ₂ O + Na ₂ O + K ₂ O) is preferably 0.01 or more, more preferably 0.02 or more, and still more preferably 0.03 or more.
On the other hand, the ratio of Li ₂ O to the mass sum of Li ₂ O, Na ₂ O and K ₂ O is preferably 1.00 or less. Thereby, the viscosity is not too low, and a glass that is easy to form can be obtained. Therefore, it is preferably 1.00 or less, more preferably 0.90 or less, and still more preferably 0.70 or less.

When the total (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) exceeds 0%, the desired refractive index or dispersion Can be adjusted. Therefore, the content of the RO component is preferably more than 0%, more preferably more than 0.5%, still more preferably more than 1.5%.
On the other hand, the total content of RO components is preferably less than 15.0%. Thereby, the fall of the refractive index of glass and the fall of devitrification resistance by excess content of RO component can be suppressed. Therefore, the mass sum of the RO component is preferably less than 15.0%, more preferably 14.0% or less, and further preferably 13.0% or less.

The total (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, Yb) is preferably less than 10.0%. Thus, due to excessive content of Ln ₂ O ₃ component is suppressed and decline in devitrification of the refractive index of the glass. Therefore, the mass sum of the Ln ₂ O ₃ component is preferably less than 10.0%, more preferably 8.5% or less, and still more preferably 7.0% or less.

<About ingredients that should not be contained>
Next, the components which should not be contained in the optical glass of the present invention and the components which should not be contained are described.

Other components can be added as needed as long as the properties of the glass of the present invention are not impaired. However, each transition metal component such as Ti, Zr, Nb, W, La, Gd, Y, Yb, Lu excluding V, Cr, Mn, Fe, Co, Ni, Cu, Ag and Mo is independent. In the case of an optical glass using a wavelength in the visible range, it is preferable that the glass be substantially free of light, because the glass is colored even when contained in a small amount in a complex or causes absorption at a specific wavelength in the visible range. .

Further, lead compounds and As ₂ O ₃ or the like arsenic compound such as PbO, because environmental load is highly components, it does not substantially contained, i.e., it is desirable not to contain any except inevitable contamination.

Furthermore, Th, Cd, Tl, Os, Be, and Se components tend to refrain from use as harmful chemical substances in recent years, and they are not only used in glass manufacturing processes but also in processing processes and disposal after productization. All environmental measures are needed. Therefore, when emphasizing environmental impact, it is preferable not to contain these substantially.

[Production method]
The optical glass of the present invention is produced, for example, as follows. That is, the above raw materials are uniformly mixed so that each component is within a predetermined content range, and the prepared mixture is put into a platinum crucible, a quartz crucible or an alumina crucible and roughly melted, and then a gold crucible and a platinum crucible , Put in a platinum alloy crucible or iridium crucible, melt for 3 to 5 hours in a temperature range of 1000 to 1400 ° C, stir and homogenize, perform bubble breakage, etc., and then lower to a temperature of 900 to 1200 ° C and then finish stirring. It is produced by removing the cord, casting in a mold and annealing.

<Physical properties>
The optical glass of the present invention has a high refractive index and an Abbe number in a predetermined range.
The refractive index (n _d ) of the optical glass of the present invention is preferably 1.65 or more, more preferably 1.67 or more, and still more preferably 1.68 or more. The upper limit of the refractive index is preferably 1.80 or less, more preferably 1.79 or less, and more preferably 1.78 or less.
The Abbe number (ν _d ) of the optical glass of the present invention is preferably 25.0, more preferably 27.0, still more preferably 29.0. On the other hand, the Abbe number (ν _d ) of the optical glass of the present invention is preferably 40.0, more preferably 39.0, still more preferably 38.0.
The optical glass of the present invention having such refractive index and Abbe number is useful for optical design, and the optical system can be miniaturized while achieving particularly high imaging characteristics etc. You can spread the degree.

Here, the optical glass of the present invention is a refractive index _{(n d)} and Abbe number ([nu _d) _{is, (- 0.01 × ν d +2.01} ) ≦ n d ≦ (-0.01 × ν d +2 It is preferable to satisfy the relationship of .12). The glass composition specified in the present invention refractive index (n _d) and Abbe number ([nu _d) is even satisfy this relationship, obtain a stable glass.
Accordingly, in the optical glass of the present invention refractive index _{(n d)} and Abbe number ([nu _d) is, it is preferable to satisfy _{_{n d ≧ (-0.01 × ν d}} +2.01) relations, _{n d} ≧ It is more preferable to satisfy the relationship of (−0.01 × ν _d +2.03).
On the other hand, in the optical glass of the present invention, the refractive index (n) and the Abbe number (v _d ) preferably satisfy the relationship of n _d ≦ (−0.01 × v _d +2.12), n _d ≦ It is more preferable to satisfy the relationship of (−0.01 × ν _d +2.11).

The optical glass of the present invention has a low partial dispersion ratio (θg, F).
More specifically, the partial dispersion ratio of the optical glass of the present invention ([theta] g, F) is between the Abbe number _{(ν d), (- 0.00162} × ν d +0.620) ≦ (θg, F It is preferable to satisfy the following relationship: ≦ (−0.00162 × v _d +0.657).
Therefore, in the optical glass of the present invention, the partial dispersion ratio (θg, F) and the Abbe number (ν _d ) preferably satisfy the relationship of θg, Fθ (−0.00162 × ν _d +0.620), It is more preferable to satisfy the relationship of θg, F ≧ (−0.00162 × ν _d +0.630).
On the other hand, in the optical glass of the present invention, the partial dispersion ratio (θg, F) and the Abbe number (( _d ) preferably satisfy the relationship of θg, F ≦ (−0.00162 × _{d d} + 0.657) It is more preferable to satisfy the relationship of θ g, F ≦ (−0.00162 × v _d +0.650).
As a result, an optical glass having a low partial dispersion ratio (θg, F) can be obtained, and the optical element formed of this optical glass can be used to reduce the chromatic aberration of the optical system.

In particular, in a region where the Abbe number (v _d ) is small, the partial dispersion ratio (θg, F) of a general glass is higher than that of the normal line, and the abscissa axis represents the Abbe number (v _d ) and the ordinate axis The relationship between the general glass partial dispersion ratio (θg, F) and the Abbe number (ν _d ) when taking the partial dispersion ratio (θg, F) is represented by a curve with a larger slope than the normal line . In the above-mentioned partial dispersion ratio (θg, F) and Abbe's number () _d ) relations, partial straight line with a larger slope than that of the normal line is used to define these relations to make partial dispersions more than general glasses. It indicates that a small glass of ratio (θg, F) can be obtained.

In the optical glass of the present invention, the temperature coefficient (dn / dT) of the relative refractive index takes a low value.
More specifically, the temperature coefficient of the relative refractive index of the optical glass of the present invention is preferably + 6.0 × 10 ⁻⁶ ° C. ⁻¹ , more preferably + 5.5 × 10 ⁻⁶ ° C. ⁻¹ , more preferably The upper limit value may be + 5.0 × 10 ⁻⁶ ° C. ^−1, and the upper limit value or a lower value (negative side) may be taken.
On the other hand, the temperature coefficient of the relative refractive index of the optical glass of the present invention is preferably -2.0 x 10 ^-6 ° C ^-1 , more preferably -1.0 x 10 ^-6 ° C ^-1 , still more preferably- The lower limit value may be 0.5 × 10 ⁻⁶ ° C. ⁻¹ and the lower limit value or a value higher than that lower limit (plus side) can be taken.
Among these, as a glass having a refractive index (n _d ) of 1.65 or more and an Abbe number (ν _d ) of 20 or more and 35 or less, many glasses having a low temperature coefficient of relative refractive index are present. In addition, it is possible to expand the options of correction such as imaging shift due to temperature change and make the correction easier. Therefore, by setting the temperature coefficient of the relative refractive index in such a range, it is possible to contribute to the correction of the image shift due to the temperature change and the like.
The temperature coefficient of the relative refractive index of the optical glass of the present invention is the temperature coefficient of the refractive index (589.29 nm) in air at the same temperature as the optical glass, and when the temperature is changed from 40 ° C. to 60 ° C. It is represented by the amount of change per 1 ° C. (° C. ⁻¹ ).

The optical glass of the present invention preferably has an average linear thermal expansion coefficient α at 100 to 300 ° C. of 75 (10 ⁻⁷ ° C. ⁻¹ ) or more. That is, the average linear thermal expansion coefficient α of the optical glass of the present invention at 100 to 300 ° C is preferably 75 (10 ^-7 ° C ^-1 ) or more, more preferably 80 (10 ^-7 ° C ^-1 ) or more, more preferably The lower limit is 85 (10 ^-7 ° C ^-1 ) or more.
Generally, when the average linear thermal expansion coefficient α is large, the glass is likely to be cracked during processing, so it is desirable that the value of the average linear thermal expansion coefficient α be as small as possible. On the other hand, from the viewpoint of joining in combination with a glass material having a low relative refractive index temperature coefficient and a large value of the average linear thermal expansion coefficient α, the value of the glass material and the average linear thermal expansion coefficient α are the same or approximate Is desirable.
Among these, in the glass having a refractive index (n _d ) of 1.65 or more and an Abbe number (ν _d ) of 25 or more and 40 or less, the glass material having a large average linear thermal expansion coefficient α is small, and the low refractive index When used in combination with a low dispersion glass material, it is more useful to have a large average linear thermal expansion coefficient α as in the present invention.

[Preform and Optical Element]
A glass molded body can be produced from the produced optical glass, for example, by means of mold press molding such as reheat press molding and precision press molding. That is, a preform for mold press molding is produced from optical glass, and the preform is subjected to reheat press molding and then subjected to polishing processing to produce a glass molded body, for example, to polishing processing. The glass preform can be manufactured by performing precision press molding on the preform. In addition, the means to produce a glass forming body is not limited to these means.

The glass molded body produced in this manner is useful for various optical elements, and among them, it is particularly preferable to use it for applications of optical elements such as lenses and prisms. This reduces color bleeding due to chromatic aberration in the transmitted light of the optical system in which the optical element is provided. Therefore, when this optical element is used for a camera, the object to be photographed can be expressed more accurately, and when this optical element is used for a projector, a desired image can be projected with higher definition.

Composition of Examples (No. 1 to No. 13) of the present invention and Comparative Examples, and refractive index (n _d ), Abbe number (( _d ), partial dispersion ratio (θ g, F), average linear thermal expansion coefficient The temperature coefficient (dn / dT) of the relative refractive index of glass (100-300 ° C.) is shown in Tables 1 and 2. The following examples are for the purpose of illustration only, and are not limited to these examples.

The glasses of the examples and comparative examples all have high purity, which are used for ordinary optical glasses such as oxides, hydroxides, carbonates, nitrates, fluorides, metaphosphoric acid compounds and the like respectively corresponding to the raw materials of the respective components. Raw materials are selected, weighed and uniformly mixed so that the proportions of the compositions of the respective examples and comparative examples shown in the table are obtained, and then a stone crucible (a platinum crucible or an alumina crucible is used depending on the melting property of glass) The solution is placed in an electric furnace and melted in an electric furnace for 0.5 to 5 hours in a temperature range of 1100 Then, the temperature was lowered to 1000 to 1200 ° C. to stir and homogenize, and then cast into a mold and gradually cooled to produce a glass.

The refractive index (n _d ), Abbe number (ν _d ) and partial dispersion ratio (θg, F) of the glasses of Examples and Comparative Examples were measured based on Japan Optical Glass Industrial Standard JOGIS 01-2003.

The temperature coefficient (dn / dT) of the relative refractive index of the glass of the example and the comparative example is the method described in Japan Optical Glass Industry Standard JOGIS 18-2008 “Method of measuring the temperature coefficient of the refractive index of optical glass”. The value of the temperature coefficient of relative refractive index at 40-60 ° C. was measured by interferometry for light of wavelength 589.29 nm.

Further, the average linear thermal expansion coefficient (100-300 ° C.) of the glass of the example and the comparative example is the temperature and the elongation of the sample according to the Japan Optical Glass Industrial Standard JOGIS 08-2003 “Method of measuring the thermal expansion of optical glass”. It calculated | required from the thermal expansion curve obtained by measuring the relationship of.

The optical glass of the embodiment of the present invention has a refractive index (n _d ) of 1.65 or more, more specifically 1.67 or more, and the refractive index (n _d ) of 1.80 or less. , Was within the desired range.
In addition, the optical glasses according to the examples of the present invention each have an Abbe number (v _d ) of 25 or more, more specifically 29 or more, and the Abbe number (v _d ) of 40 or less. It was inside.

As shown in these tables, the optical glass of the embodiment of the present invention has a partial dispersion ratio (θg, F) and an Abbe number (ν _d ) of (−0.00162 × ν _d +0.620) ≦ (θg, F) (−0.00162 × ν _d +0.657), and more specifically, (−0.00162 × νd + 0.650) ≦ (θg, F) ≦ (−0.00162 × ν _d) The relationship of +0.630 was satisfied. That is, the relationship between the partial dispersion ratio (θg, F) and the Abbe number (ν _d ) for the glass of the example of the present application is as shown in FIG.
On the other hand, the optical glass of the comparative example did not satisfy the relationship of (−0.00162 × v _d +0.620) ≦ (θg, F) ≦ (−0.00162 × v _d +0.657).

In addition, the optical glass of the embodiment of the present invention has a refractive index (n _d ) and an Abbe number (ν _d ) of (−0.01 × ν _d +2.01) ≦ n _d ≦ (−0.01 ×) It satisfies the relationship of _{d d} + 2.12), and more specifically satisfies the relationship of (−0.01 × ν _d +2.03) ≦ n _d ≦ (−0.01 × ν _d + 2.11) The That is, the relationship between the refractive index (n _d ) and the Abbe number (v _d ) for the glass of the example of the present application is as shown in FIG.

As shown in the table, all the optical glasses of the examples have temperature coefficients of relative refractive index within the range of + 6.0 × 10 ⁻⁶ to −0.5 × 10 ⁻⁶ (° C. ⁻¹ ). , Was within the desired range.

In addition, the optical glass of the present invention had an average linear thermal expansion coefficient α at 100 to 300 ° C. of 80 (10 ⁻⁷ ° C. ⁻¹ or more).

Furthermore, a glass block was formed using the optical glass of the embodiment of the present invention, and this glass block was ground and polished to be processed into a lens and a prism shape. As a result, it could be stably processed into various lens and prism shapes.

Although the present invention has been described in detail for the purpose of illustration, the present embodiment is for the purpose of illustration only, and many modifications can be made by those skilled in the art without departing from the spirit and scope of the present invention. Will be understood.

Claims

In mass%,
SiO 2 component 15.0 to 45.0%
Nb 2 O 5 component 10.0 to 40.0%
Na 2 O ingredient more than 0 ~ 20.0%
5.0 to 20.0% by mass (ZrO 2 + Li 2 O),
Containing a mass ratio (BaO / MgO + CaO + SrO + BaO) of 0.90 or less,
The partial dispersion ratio (θg, F) is between the Abbe number (ν d ),
The temperature coefficient (40 to 100) of the relative refractive index (589.29 nm) is satisfied, which satisfies the relationship of (−0.00162 × ν d +0.620) ≦ (θg, F) ≦ (−0.00162 × ν d + 0.657) Optical glass having a temperature of 60 ° C. in the range of + 6.0 × 10 −6 to −5.0 × 10 −6 (° C. −1 ).
The weight ratio (Li 2 O / Li 2 O + Na 2 O + K 2 O) according to claim 1 optical glass, wherein a is 1.00 or less.
Refractive index (n d) and Abbe number ([nu d) is, (- 0.01 × ν d +2.01 ) satisfies the relationship of ≦ n d ≦ (-0.01 × ν d +2.12) according to claim 1 Or 2 optical glass.
A preform material comprising the optical glass according to any one of claims 1 to 3.
An optical element comprising the optical glass according to any one of claims 1 to 3.
An optical apparatus comprising the optical element according to claim 5.