CN109592898B

CN109592898B - Optical glass, preform and optical element

Info

Publication number: CN109592898B
Application number: CN201811144057.3A
Authority: CN
Inventors: 岩崎菜那
Original assignee: Ohara Inc
Current assignee: Ohara Inc
Priority date: 2017-10-02
Filing date: 2018-09-29
Publication date: 2023-09-19
Anticipated expiration: 2038-09-29
Also published as: CN109592898A

Abstract

The subject of the application is to obtain an optical glass, a preformed material and an optical element, wherein the refractive index (n _d ) Abbe number (v) _d ) In the expected range, and the partial dispersion ratio (thetag, F) is small. The optical glass contains SiO in mass percent ₂ 20.0 to 45.0 percent of Nb ₂ O ₅ 25.0 to 60.0 percent of components, tiO ₂ 0 to 5.0% of components (Li ₂ O/Na ₂ O+K ₂ O) is between 0.40 and 1.00, the partial dispersion ratio (thetag, F) and Abbe number (v) _d ) Satisfies (-0.00162 Xv) _d +0.620)≤(θg，F)≤(‑0.00162×ν _d The relation of +0.657) and the temperature coefficient (40-60 ℃) of the relative refractive index (589.29 nm) is +6.0X10 ^‑6 ～‑5.0×10 ^‑6 (℃ ^‑1 ) Within a range of (2).

Description

Optical glass, preform and optical element

Technical Field

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

Background

Optical systems such as digital cameras and video cameras contain more or less bleeding called aberrations. The aberration is classified into monochromatic aberration and chromatic aberration, particularly chromatic aberration, and depends largely on the material characteristics of lenses used in the optical system.

In general, chromatic aberration is corrected by a combination of a low-dispersion convex lens and a high-dispersion concave lens, but such a combination can correct only aberrations of a red region and a green region, and aberrations of a blue region still exist. This aberration that cannot remove the clean blue region is called the secondary spectrum. When correcting the secondary spectrum, an optical design is required that considers the g-line (435.835 nm) movement of the blue region. In this case, the partial dispersion ratio (θg, F) is used as an optical characteristic index which is a focus of optical design. In the optical system in which the low-dispersion lens and the high-dispersion lens are combined, the low-dispersion lens uses an optical material having a large partial dispersion ratio (θg, F), and the high-dispersion lens uses an optical material having a small partial dispersion ratio (θg, F), whereby the secondary spectrum can be corrected well.

The partial dispersion ratio (θg, F) is represented by the following formula (1).

θg，F＝(n _g -n _F )/(n _F -n _C )……(1)

In the optical glass, the ratio of partial dispersion (thetag, F) and Abbe number (v) of the partial dispersion in the short wavelength region are expressed _d ) There is a substantially linear relationship between them. The straight line showing the relationship has a vertical axis of the partial dispersion ratio (thetag, F) and an Abbe number (v) _d ) The orthogonal coordinates of the horizontal axis are represented by a straight line drawn by 2 points of the abbe number and the partial dispersion ratio of NSL7 and PBM2, and this straight line is referred to as a normal line (see fig. 1). Standard glass, which is a standard for normal lines, varies from optical glass manufacturer to optical glass manufacturer, but each manufacturer is defined by almost the same inclination and intercept. (NSL 7 and PBM2 are optical glasses manufactured by Nigaku Kogyo Co., ltd., abbe number (. Nu.) of PBM2 _d ) An Abbe number (. Nu.) of 36.3, a partial dispersion ratio (. Theta.g, F) of 0.5828, NSL7 _d ) 60.5, and a partial dispersion ratio (. Theta.g, F) of 0.5436. )

In recent years, due to the demand for optical design, as an optical material having a small partial dispersion ratio (θg, F), an optical material having an abbe number (v) of 25 to 40 is more used _d ) Is a glass of (a).

In recent years, optical elements incorporated in optical devices for vehicles such as in-vehicle cameras and optical devices for optical devices that generate a large amount of heat such as projectors, copiers, laser printers, and broadcasting devices have been used in environments with higher temperatures. In such a high-temperature environment, the temperature of the optical element constituting the optical system tends to vary greatly when in use, and this temperature often reaches 100 ℃ or higher. In this case, since adverse effects of temperature fluctuation on imaging characteristics and the like of the optical system are large enough to be ignored, it is desirable to construct an optical system which is difficult to affect imaging characteristics and the like even if temperature fluctuation occurs.

When an optical element composed of glass having a negative temperature coefficient of relative refractive index is used together with an optical element composed of glass having a positive temperature coefficient of relative refractive index and a negative temperature coefficient of relative refractive index is used when the temperature is increased, it is preferable that the influence on imaging characteristics and the like due to temperature change can be corrected when the optical element is composed of glass having a negative temperature coefficient of relative refractive index and the like, which is hardly influenced by temperature fluctuation.

On the other hand, in an optical material having a small partial dispersion ratio (θg, F), the optical material is obtained by adding a component (e.g., nb ₂ O ₅ Component, la ₂ O ₃ Components, etc.), the temperature coefficient of the relative refractive index tends to be large. As such an optical glass, for example, a glass composition as shown in patent document 1 is known.

In particular, in-vehicle lenses, exchange lenses, and the like that have been used in recent years have been increasingly used in various environments, and therefore, there is a need for an optical glass that has a small partial dispersion ratio (θg, F) and a small temperature coefficient of relative refractive index.

Prior art literature

Patent document 1 Japanese patent laid-open No. 58-125637

Disclosure of Invention

However, the glass disclosed in patent document 1 is Nb in which the partial dispersion ratio is reduced ₂ O ₅ Low content of components, while TiO ₂ The amount is large and therefore insufficient for use as a lens for correcting the secondary spectrum. Moreover, it cannot be said that the alkali metal content is small and the temperature coefficient of the relative refractive index is small.

The present application has been made in view of the above-described problems, and an object thereof is to obtain an optical glass having a refractive index (n _d ) Abbe number (v) _d ) The partial dispersion ratio (thetag, F) is relatively high within the desired rangeSmall and has a small temperature coefficient of relative refractive index.

As a result of intensive studies to solve the above problems, the inventors have found that SiO is contained ₂ Component and Nb ₂ O ₅ In the glass with the components, tiO is prepared by ₂ The present application has been completed by limiting the component content to 5.0% or less, and obtaining an optical glass having a high refractive index and abbe number (high dispersion) in a desired range, a low partial dispersion ratio, and a low temperature coefficient of relative refractive index.

(1) An optical glass comprising, in mass%, siO ₂ 20.0 to 45.0 percent of component and Nb ₂ O ₅ 25.0 to 60.0 percent of components and TiO ₂ 0 to 5.0% of components (Li ₂ O/Na ₂ O+K ₂ O) is between 0.40 and 1.00, the partial dispersion ratio (thetag, F) and Abbe number (v) _d ) Satisfies (-0.00162 Xv) _d +0.620)≤(θg，F)≤(-0.00162×ν _d The relation of +0.657) and the temperature coefficient (40-60 ℃) of the relative refractive index (589.29 nm) is +6.0X10 ^-6 ～-5.0×10 ^-6 (℃ ^-1 ) Within a range of (2).

(2) The optical glass according to (1), wherein the mass ratio (Rn ₂ O/Nb ₂ O ₅ ) Wherein Rn is at least one selected from the group consisting of Li, na and K, and is 0.50 or less.

(3) The optical glass according to (1) or (2), having a refractive index (n _d ) Abbe number (v) _d ) Meets (-0.01 Xv) _d +2.03)≤nd≤(-0.01×ν _d +2.13).

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

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

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

According to the present application, an optical glass having a refractive index (n _d ) Abbe number (v) _d ) In the expected range, the partial dispersion is relatively low and the relative refractive index is relatively lowThe temperature coefficient of (c) is small.

Drawings

FIG. 1 shows Abbe number (. Nu.) with the longitudinal axis of the partial dispersion ratio (. Theta.g, F) _d ) A normal line schematic diagram represented by rectangular coordinates of a horizontal axis;

FIG. 2 is a graph showing the partial dispersion ratio (θg, F) and Abbe number (v) of an embodiment of the application _d ) Schematic representation of the relationship;

FIG. 3 is a graph showing refractive index (n _d ) With Abbe number (v) _d ) Is a schematic diagram of the relationship of (a).

Detailed Description

The optical glass of the present application is characterized by comprising SiO in terms of mass% of oxide composition ₂ 20.0 to 45.0 percent of component and Nb ₂ O ₅ 25.0 to 60.0 percent of components and TiO ₂ 0 to 5.0% of component (Li) ₂ O/Na ₂ O+K ₂ O) is 0.40 to 1.00, and the ratio of partial dispersion (thetag, F) to Abbe number (v) _d ) Satisfies (-0.00162 Xv) _d +0.620)≤(θg，F)≤(-0.00162×ν _d +0.657), the temperature coefficient of the relative refractive index is small.

Contains a specified amount of SiO ₂ Component, nb ₂ O ₅ The component (C) contains less than 5.0% of TiO ₂ The optical glass having the components can obtain a glass having a high refractive index, an Abbe number (high dispersion) and a low partial dispersion ratio in a desired range. In particular, by making TiO ₂ The content of (C) is kept below 5.0%, and the temperature coefficient of the relative refractive index can be reduced while keeping the partial dispersion ratio (thetag, F) small.

Therefore, a refractive index (n) having a desired high refractive index _d ) Low abbe number (v) _d ) Meanwhile, the optical glass with smaller partial dispersion ratio (thetag, F) is beneficial to reducing chromatic aberration of an optical system and smaller temperature coefficient of relative refractive index.

The embodiments of the optical glass according to the present application will be described in detail below, but the present application is not limited to the following embodiments, and can be implemented with appropriate modifications within the scope of the object of the present application. Note that, although the description of the parts to be repeated is omitted appropriately, the gist of the application is not limited thereto.

[ glass component ]

The composition ranges of the respective components constituting the optical glass of the present application are as follows. In the present specification, unless otherwise specified, the content of each component is expressed as mass% relative to the total mass of the glass in terms of oxide composition. The term "oxide conversion composition" as used herein means a composition of each component contained in the glass, assuming that all of the oxides, complex salts, metal fluorides and the like used as raw materials of the glass constituent components of the present application are decomposed to become oxides at the time of melting, the total mass of the oxide to be formed is set to 100 mass%.

< essential component, optional component >

SiO ₂ The components are essential components that promote stability of glass formation, lower liquidus temperatures, and reduce unwanted devitrification (generation of crystals) in the optical glass.

In particular, by incorporating SiO ₂ The content of the component is 20.0% or more, and a glass excellent in devitrification resistance can be obtained without greatly increasing the partial dispersion ratio. In addition, devitrification and coloration can be reduced. Thus, siO ₂ The content of the component (a) is preferably 20.0% or more, more preferably 23.0% or more, and still more preferably 25.0% or more.

On the other hand, by combining SiO ₂ The content of the component is 45.0% or less, and the refractive index is hardly lowered, so that the desired high refractive index can be easily obtained, and the increase of the partial dispersion ratio can be suppressed. In addition, the decrease in the melting property of the glass raw material can be suppressed. Thus, siO ₂ The content of the component (a) 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.

SiO ₂ SiO may be used as the component ₂ 、K ₂ SiF ₆ 、Na ₂ SiF ₆ Etc. as raw materials.

Nb ₂ O ₅ Composition of the componentsAs an essential component, it can increase refractive index, reduce abbe number and partial dispersion ratio, and can improve devitrification resistance.

In particular, by adding Nb to ₂ O ₅ The content of the component is 25.0% or more, and the refractive index is increased until the target optical constant is reached by adjusting the content within the range of the present application, whereby anomalous dispersion can be reduced. Thus, nb ₂ O ₅ The content of the component (a) is preferably 25.0% or more, more preferably 30.0% or more, and still more preferably 35.5% or more.

On the other hand, by Nb ₂ O ₅ The content of the component (A) is 60.0% or less, and the cost of the glass material can be reduced. In addition, the melting temperature rise during glass production can be suppressed, and the Nb content can be reduced ₂ O ₅ Devitrification caused by excessive content of the components. In addition, the chemical durability of the glass can be improved. Thus, nb ₂ O ₅ The content of the component (a) is preferably 60.0% or less, more preferably 55.0% or less, still more preferably 50.0% or less, and still more preferably 48.0% or less.

Nb ₂ O ₅ The component (A) may be Nb ₂ O ₅ Etc. as raw materials.

TiO ₂ When the content of the component (a) is more than 0%, the refractive index can be increased, the Abbe number can be reduced, and the devitrification resistance can be improved. On the other hand, if the content is too large, the partial dispersion ratio becomes large.

Thus, by combining TiO ₂ The content of the component (A) is 5.0% or less, whereby the coloring of the glass can be reduced and the internal transmittance can be improved. In addition, the partial dispersion ratio is hard to rise, and a desired low partial dispersion ratio close to the normal line is easily obtained. Thus, tiO ₂ The content of the component (a) is preferably 5.0% or less, more preferably 4.8% or less, and still more preferably less than 4.5%.

TiO ₂ The component (A) may be TiO ₂ Etc. as raw materials.

K ₂ The O component is an optional component, and when the content is more than 0%, the thermal expansion coefficient can be increased, and the temperature of the relative refractive index can be increasedThe coefficient of degree becomes smaller.

Thus, K is ₂ The content of the O component is preferably more than 0%, more preferably more than 0.3%, and most preferably more than 0.5%.

On the other hand, by combining K ₂ The content of the O component is 10.0% or less, whereby the increase in the partial dispersion ratio can be suppressed and devitrification can be reduced. Thus, K is ₂ The content of the O component is preferably 10.0% or less, more preferably less than 8.0%, and still more preferably less than 5.0%.

K ₂ The component O may be K ₂ CO ₃ 、KNO ₃ 、KF、KHF ₂ 、K ₂ SiF ₆ Etc. as raw materials.

B ₂ O ₃ When the content of the component (a) is more than 0%, the stability of glass formation is promoted, and the liquid phase temperature can be lowered, so that devitrification resistance can be improved and the melting property of the glass raw material can be improved. Thus B ₂ O ₃ The content of the component (a) is preferably more than 0%, more preferably more than 0.3%, and even more preferably more than 0.5%.

On the other hand, by combining B ₂ O ₃ The content of the component is 7.0% or less, whereby lowering of the refractive index can be suppressed, and the increase of the partial dispersion ratio can be suppressed, and further, the deterioration of the chemical durability of the glass can be improved. Thus B ₂ O ₃ The content of the component (a) is preferably 7.0% or less, more preferably 6.0% or less, and still more preferably 5.0% or less.

B ₂ O ₃ The component (A) may be H ₃ BO ₃ 、Na ₂ B ₄ O ₇ 、Na ₂ B ₄ O ₇ ·10H ₂ O、BPO ₄ Etc. as raw materials.

Li ₂ When the content of the O component is more than 0%, the partial dispersion ratio can be reduced, the transmittance can be improved, the liquid phase temperature can be reduced, and the melting property of the glass raw material can be improved. Thus Li ₂ The content of the O component is preferably more than 0%, more preferably more than 1.0%, and even more preferably more than 3.0%.

On the other hand, by mixing Li ₂ The content of the O component is 15.0% or less, whereby lowering of the refractive index can be suppressed and devitrification due to excessive content can be reduced.

Thus Li ₂ The content of the O component is preferably 15.0% or less, more preferably 10.0% or less, and still more preferably less than 7.0%.

Li ₂ As the O component, li may be used ₂ CO ₃ 、LiNO ₃ LiF, etc. as raw materials.

Na ₂ When the content of the O component is more than 0%, the partial dispersion ratio can be reduced, the thermal expansion coefficient can be increased, and the temperature coefficient of the relative refractive index can be reduced. Thus, na ₂ The content of the O component is preferably more than 0%, more preferably more than 1.0%, and still more preferably more than 3.0%.

On the other hand, by Na ₂ The content of the O component is 15.0% or less, whereby lowering of the refractive index can be suppressed and devitrification due to excessive content can be reduced.

Thus, na ₂ The content of the O component is preferably 15.0% or less, more preferably 10.0% or less, and still more preferably less than 8.0%.

Na ₂ As the O component, na may be used ₂ CO ₃ 、NaNO ₃ 、NaF、Na ₂ SiF ₆ Etc. as raw materials.

Rn ₂ The sum (mass sum) of the contents of the O component (wherein Rn is at least one selected from the group consisting of Li, na, and K) is greater than 0%, the temperature coefficient of the relative refractive index can be reduced. Thus Rn ₂ The sum of the O components is preferably more than 0%, more preferably more than 3.0%, more preferably more than 5.0%, more preferably more than 8.0%.

On the other hand, by combining Rn ₂ The sum (mass sum) of the contents of O components (wherein Rn is at least one selected from the group consisting of Li, na and K) is 20.0% or less, and the viscosity in the glass can be reinforced, thereby improving the formability. Therefore, it is preferably 20.0% or less, more preferably 19.0% or less, and still more preferablyIs less than 18.0%.

ZrO ₂ When the content of the component (a) is more than 0%, the refractive index and abbe number of the glass can be increased, the partial dispersion ratio can be reduced, and the devitrification resistance can be improved. In addition, devitrification and coloration can be reduced. Thus, zrO ₂ The content of the component (a) is preferably more than 0%, more preferably more than 1.0%, even more preferably more than 3.0%.

On the other hand, by introducing ZrO ₂ The content of the component is 15.0% or less, so that devitrification can be reduced and a homogeneous glass can be easily obtained. Thus, zrO ₂ The upper limit of the content of the component (a) is preferably 15.0% or less, more preferably 10.0% or less, and even more preferably 8.0% or less.

ZrO ₂ As the component (A), zrO may be used ₂ 、ZrF ₄ Etc. as raw materials.

When the MgO component is an arbitrary component and the content thereof is more than 0%, the melting temperature of the glass can be lowered.

On the other hand, by setting the content of the MgO component to 10.0% or less, devitrification can be reduced while suppressing a decrease in 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%.

MgO component, mgO, mgCO and the like can be used ₃ 、MgF ₂ Etc. as raw materials.

When the CaO component is an arbitrary component and the content thereof is more than 0%, the abbe number and devitrification can be reduced and the melting property of the glass raw material can be improved while reducing the cost of the glass material.

On the other hand, by setting the CaO content to 10.0% or less, the decrease in refractive index and the increase in abbe number, and the increase in the partial dispersion ratio can be suppressed, and the devitrification can be reduced. Therefore, the content of the CaO component is preferably 10.0% or less, more preferably less than 7.0%, and still more preferably less than 5.0%.

CaO component, caCO, etc. may be used ₃ 、CaF ₂ Etc. as raw materials.

When the content of the SrO component is more than 0%, the refractive index can be improved and the devitrification resistance can be improved.

In particular, by setting the content of the SrO component to 10.0% or less, deterioration of 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%.

SrO component may be Sr (NO) ₃ ) ₂ 、SrF ₂ Etc. as raw materials.

When the BaO component is an arbitrary component and the content thereof is more than 0%, the refractive index and the devitrification resistance can be improved, and the thermal expansion coefficient can be increased, and the temperature coefficient of the relative refractive index can be decreased.

In particular, by setting the content of the BaO component to 5.0% or less, it is possible to suppress a decrease in refractive index and an increase in abbe number, and an increase in partial dispersion ratio, and to reduce devitrification. Therefore, the content of the BaO component is preferably 5.0% or less, more preferably less than 4.0%, still more preferably less than 3.0%, and still more preferably less than 1.0%.

BaO component, baCO can be used ₃ 、Ba(NO ₃ ) ₂ Etc. as raw materials.

When the content of the ZnO component is more than 0%, the glass is inexpensive, the devitrification resistance can be improved, and the glass transition point can be reduced. Accordingly, the content of the ZnO component is preferably more than 0%, more preferably more than 0.1%, and even more preferably more than 0.3%.

On the other hand, by setting the content of the ZnO component to 10.0% or less, devitrification and coloration can be reduced. Therefore, the content of the ZnO component is preferably 10.0% or less, more preferably 8.0% or less, and even more preferably less than 6.0%.

La ₂ O ₃ Component, gd ₂ O ₃ Component, Y ₂ O ₃ Composition and Yb ₂ O ₃ The component (A) is an arbitrary component, and when the content of at least one component is more than 0%, the refractive index can be increased and the partial dispersion ratio can be reduced.

In particular, by combiningLa ₂ O ₃ Component, gd ₂ O ₃ Component, Y ₂ O ₃ Composition and Yb ₂ O ₃ The content of each component is 10.0% or less, which can suppress the increase of Abbe number, reduce devitrification and reduce material cost. Therefore La ₂ O ₃ Component, gd ₂ O ₃ Component, Y ₂ O ₃ Composition and Yb ₂ O ₃ The content of each component is preferably 10.0% or less, more preferably 7.0% or less, and still more preferably less than 5.0%.

La ₂ O ₃ Component, gd ₂ O ₃ Component, Y ₂ O ₃ Composition and Yb ₂ O ₃ La can be used as the component ₂ O ₃ 、La(NO ₃ ) ₃ ·XH ₂ O (X is an arbitrary integer), Y ₂ O ₃ 、YF ₃ 、Gd ₂ O ₃ 、GdF ₃ 、Yb ₂ O ₃ Etc. as raw materials.

Ta ₂ O ₅ When the content of the component (a) is more than 0%, the refractive index can be increased, the Abbe number and the partial dispersion ratio can be reduced, and the devitrification resistance can be improved.

On the other hand, by combining Ta ₂ O ₅ The content of the component is 10.0% or less, and Ta, which is a scarce mineral resource, can be reduced ₂ O ₅ The amount of the components used and the glass is more easily melted at a low temperature, so that the production cost of the glass can be reduced. In addition, the Ta factor can be reduced thereby ₂ O ₅ The glass is devitrified due to excessive content of the components. Thus, ta ₂ O ₅ The content of the component (a) 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, from the viewpoint of reducing the material cost of the glass, ta may not be contained ₂ O ₅ The components are as follows.

Ta ₂ O ₅ The component (A) may be Ta ₂ O ₅ Etc. as raw materials.

WO ₃ The component (A) is optional, and when the content is more than 0%, the refractive index can be improved and the refractive index can be reducedAbbe number, devitrification resistance and melting property of glass raw materials are improved.

On the other hand, by combining WO ₃ The content of the component is 10.0% or less, whereby the partial dispersion ratio of the glass is hardly increased, and the internal transmittance is improved by reducing the coloring of the glass. Thus, WO ₃ The content of the component (a) 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 The component (A) may be WO ₃ Etc. as raw materials.

P ₂ O ₅ When the content of the component (A) is more than 0%, the stability of the glass can be improved.

On the other hand, by combining P ₂ O ₅ The content of the component (B) is 10.0% or less, and the content of P can be reduced ₂ O ₅ Devitrification caused by excessive content of the components. Thus, P ₂ O ₅ The content of the component (a) is preferably 10.0% or less, more preferably less than 5.0%, and still more preferably less than 3.0%.

P ₂ O ₅ As the component (A), al (PO) ₃ ) ₃ 、Ca(PO ₃ ) ₂ 、Ba(PO ₃ ) ₂ 、BPO ₄ 、H ₃ PO ₄ Etc. as raw materials.

GeO ₂ When the content of the component (a) is more than 0%, the refractive index can be increased and devitrification can be reduced.

On the other hand, by combining GeO ₂ The content of the component is 10.0% or less, and cost-effective GeO is reduced ₂ The amount of the components used can reduce the material cost of the glass. Thus, geO ₂ The content of the component (a) is preferably 10.0% or less, more preferably less than 5.0%, and still more preferably less than 3.0%.

GeO ₂ The component may be GeO ₂ Etc. as raw materials.

Al ₂ O ₃ Composition and Ga ₂ O ₃ The components are arbitrary components, wherein when the content of at least any one of the components is more than 0%, the refractive index can be improved,and can improve devitrification resistance.

On the other hand, by combining Al ₂ O ₃ Composition and Ga ₂ O ₃ The content of each component is 10.0% or less, and the content of Al can be reduced ₂ O ₃ Component or Ga ₂ O ₃ Devitrification caused by excessive content of the components. Thus, al ₂ O ₃ Composition and Ga ₂ O ₃ The content of each component is preferably 10.0% or less, more preferably less than 5.0%, and still more preferably less than 3.0%.

Al ₂ O ₃ Composition and Ga ₂ O ₃ The component (A) may be Al ₂ O ₃ 、Al(OH) ₃ 、AlF ₃ 、Ga ₂ O ₃ 、Ga(OH) ₃ Etc. as raw materials.

Bi ₂ O ₃ When the content of the component (a) is more than 0%, the refractive index can be increased, the Abbe number can be reduced, and the glass transition point can be reduced.

On the other hand, by combining Bi ₂ O ₃ The content of the component is 10.0% or less, whereby the partial dispersion ratio is less likely to be increased, and the glass can be reduced in coloring and the internal transmittance can be improved. Therefore, bi ₂ O ₃ The content of the component (a) 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 Bi can be used as the component (A) ₂ O ₃ Etc. as raw materials.

TeO ₂ When the content of the component (a) is more than 0%, the refractive index can be increased, the partial dispersion ratio can be reduced, and the glass transition point can be lowered.

On the other hand, by combining TeO ₂ The content of the component (A) is 5.0% or less, whereby the coloring of the glass can be reduced and the internal transmittance can be improved. In addition, by reducing the cost-intensive TeO ₂ The use of the components can provide glass with low material cost. Thus, teO ₂ The content of the component (a) is preferably 5.0% or less, more preferably less than 3.0%, and still more preferably less than 1.0%.

TeO ₂ The component (A) may be TeO ₂ Etc. as raw materials.

SnO ₂ When the content of the component (a) is more than 0%, the glass after melting can be made clear (defoamed), and the visible light transmittance of the glass can be improved.

On the other hand, by reacting SnO ₂ The content of the component is 1.0% or less, and coloring of the glass or devitrification of the glass due to reduction of the molten glass can be made difficult to occur. In addition, due to SnO ₂ The alloying between the component and the melting equipment (particularly, noble metal such as Pt) is reduced, and it is desirable to extend the life of the melting equipment. Thus, snO ₂ The content of the component (a) is preferably 1.0% or less, more preferably less than 0.5%, and still more preferably less than 0.1%.

SnO ₂ The component (C) may be SnO ₂ 、SnF ₂ 、SnF ₄ Etc. as raw materials.

Sb ₂ O ₃ When the content of the component(s) in the optical glass of the present application is more than 0%, defoaming of the glass is promoted and the glass becomes clear. By mixing Sb ₂ O ₃ The content of the component (B) is 1.0% or less, so that excessive bubbles and Sb are hardly generated during melting of the glass ₂ O ₃ Alloying between the components and the melting equipment (particularly, noble metals such as Pt) is difficult to occur. Thus, sb ₂ O ₃ The content of the component (a) is preferably 1.0%, more preferably 0.8%, and even more preferably 0.6%.

Sb ₂ O ₃ The component (B) may be Sb ₂ O ₃ 、Sb ₂ O ₅ 、Na ₂ H ₂ Sb ₂ O ₇ ·5H ₂ O, etc. as raw materials.

Further, the component for clearing and defoaming glass is not limited to the above SnO ₂ Component or Sb ₂ O ₃ As the component (A), a clarifying agent, a defoaming agent or a combination of these known in the art of glass manufacturing can be used.

Li ₂ O and Na ₂ O and K ₂ The ratio of the mass sum of O is preferably 1.38 or less. This can suppress deterioration of devitrification. Therefore, mass ratio Li ₂ O/(Na ₂ O+K ₂ O) is preferably 1.38 or less, more preferably 1.00 or less, still more preferably 0.95 or less, and still more preferably 0.90 or less.

On the other hand, in the case of the mass ratio Li ₂ O/(Na ₂ O+K ₂ When O) is 0.40 or more, glass having relatively small partial dispersion can be obtained. Therefore, it is preferably 0.40 or more, more preferably 0.45 or more, and still more preferably 0.50 or more.

TiO ₂ With Li ₂ The ratio of O is preferably 1.42 or less. This can reduce devitrification of the glass. Therefore, mass ratio TiO ₂ /Li ₂ O is preferably 1.00 or less, more preferably 0.95 or less, and still more preferably 0.90 or less.

On the other hand, mass ratio TiO ₂ /Li ₂ When O is greater than 0, the transmittance is not deteriorated, and the partial dispersion ratio can be reduced. Therefore, it is preferably more than 0, more preferably 0.20 or more, still more preferably 0.25 or more, and still more preferably 0.30 or more.

Rn ₂ O component (wherein Rn is at least one selected from the group consisting of Li, na, K) and Nb ₂ O ₅ The ratio of (2) is preferably 0.50 or less. This allows the desired refractive index to be obtained, and the partial dispersion ratio to be reduced. Therefore, the mass ratio Rn ₂ O/Nb ₂ O ₅ Preferably 0.50 or less, more preferably 0.48 or less, and still more preferably 0.45 or less.

On the other hand, by combining the mass ratio Rn ₂ O/Nb ₂ O ₅ The temperature coefficient of the relative refractive index can be reduced by 0.10 or more. Therefore, it is preferably 0.10 or more, more preferably 0.20 or more, and still more preferably 0.25 or more.

SiO ₂ With Nb ₂ O ₅ The ratio of (2) is preferably 0.50 or more. This makes it possible to reduce the partial dispersion ratio and improve the stability of the glass. Therefore, the lower limit thereof is preferably 0.50 or more, more preferably 0.55 or more, and still more preferably 0.60 or more.

On the other hand, siO ₂ With Nb ₂ O ₅ The ratio of (2) is preferably 1.00 or less. Therefore, the upper limit thereof is preferably 1.00 or less, more preferably 0.95 or less, and still more preferably 0.90 or less. This can give a high refractive index and a desired abbe number.

TiO ₂ 、Nb ₂ O ₅ 、ZrO ₂ The total amount of (2) is preferably 35.0% or more. Thus, the partial dispersion ratio becomes small, and the refractive index and abbe number are desired values. Thus, the mass sum (TiO ₂ +Nb ₂ O ₅ +ZrO ₂ ) Preferably 35.0% or more, more preferably 38.0% or more, more preferably 40.0% or more, more preferably 45.0% or more.

On the other hand, mass sum (TiO ₂ +Nb ₂ O ₅ +ZrO ₂ ) Preferably 70.0% or less. This can suppress deterioration of devitrification, and the transmittance is improved. Preferably 70.0% or less, more preferably less than 65.0%, still more preferably less than 60.0%, still more preferably less than 58.0%.

ZrO ₂ With Nb ₂ O ₅ The ratio of (2) is preferably 0.01 or more. Thus, the partial dispersion ratio becomes smaller, and the devitrification is better while having a high refractive index. Therefore, mass ratio ZrO ₂ /Nb ₂ O ₅ Preferably 0.01 or more, more preferably 0.05 or more, and still more preferably more than 0.10.

On the other hand, mass ratio ZrO ₂ /Nb ₂ O ₅ Preferably 0.25 or less. This improves the stability of the glass, and can suppress the rise in the abbe number. Preferably 0.25 or less, more preferably 0.22 or less, still more preferably 0.20 or less, and still more preferably 0.15 or less.

Na ₂ O component and Rn ₂ The ratio of the O component (wherein Rn is at least one selected from the group consisting of Li, na and K) is preferably at least 0.25. Thereby, the temperature coefficient of the relative refractive index becomes small. Therefore, mass ratio Na ₂ O/Rn ₂ O is preferably 0.25 or more, more preferably 0.27 or more, and still more preferably 0.30 or more.

On the other hand, mass ratio Na ₂ O/Rn ₂ O is preferably 0.65 or less.This can suppress devitrification and a decrease in refractive index due to the reheat press molding. Preferably 0.65 or less, more preferably 0.63 or less, and still more preferably 0.60 or less.

When the sum (mass sum) of the contents of RO components (wherein R is one or more selected from the group consisting of Mg, ca, sr, ba) is more than 0%, the desired refractive index and dispersion can be adjusted. Therefore, the content of the RO component is preferably more than 0%, more preferably more than 0.5%, and still more preferably more than 1.5%.

On the other hand, the sum of the contents of RO components is preferably less than 9.0%. This can suppress the decrease in refractive index and the decrease in devitrification resistance of the glass due to the excessive inclusion of the RO component. Accordingly, the mass sum of the RO components is preferably less than 9.0%, more preferably less than 7.0%, still more preferably 6.5% or less, and still more preferably 6.0% or less.

Ln ₂ O ₃ The sum (mass sum) of the contents of the components (in the formula, ln is one or more selected from the group consisting of La, gd, Y, yb) is preferably less than 5.0%. This can suppress factor Ln ₂ O ₃ The excessive content of the components causes a decrease in refractive index of the glass and a decrease in devitrification resistance. Thus Ln ₂ O ₃ The mass sum of the components is preferably less than 5.0%, more preferably 4.5% or less, and still more preferably 4.0% or less.

< concerning the component that should not be contained >

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

Other components may be added as needed within a range not to impair the glass properties of the present application. However, when various transition metal components such as V, cr, mn, fe, co, ni, cu, ag, mo are contained alone or in a composite form in addition to Ti, zr, nb, W, la, gd, Y, yb, lu, even a small amount of the transition metal components may cause coloring of the glass and may have a property of absorbing light of a specific wavelength in the visible range, and therefore, particularly in an optical glass using a wavelength in the visible range, it is preferable that the transition metal components are substantially not contained.

In addition, lead compounds such As PbO and As ₂ O ₃ The arsenic compound is preferably substantially free of components which are highly environmentally friendly, that is, completely free of components other than unavoidable contamination.

Further, each component Th, cd, tl, os, be, se is considered as a harmful chemical substance in recent years, and tends to be avoided, and measures against environmental measures are required not only in the glass manufacturing step but also in the processing step and until the disposal after production. Therefore, from the viewpoint of importance on environmental impact, it is preferable that these components are substantially not contained.

[ method of production ]

The optical glass of the present application can be produced, for example, in the following manner. That is, the above-mentioned raw materials are uniformly mixed in a predetermined content range, and the obtained mixture is put into a platinum crucible, a quartz crucible or an alumina crucible to be preliminarily melted, and then put into a gold crucible, a platinum alloy crucible or an iridium crucible to be melted in a temperature range of 1000 to 1400 ℃ for 3 to 5 hours, and after stirring to be uniform and defoaming, the obtained mixture is cooled to a temperature of 900 to 1200 ℃ and then stirred in a final stage to remove lines, and then poured into a mold to be slowly cooled.

< physical Properties >

The optical glass of the present application has a high refractive index and an Abbe number in a predetermined range.

Refractive index (n) of the optical glass of the present application _d ) The lower limit thereof is preferably 1.70 or more, more preferably 1.72 or more, and still more preferably 1.75 or more. The upper limit of the refractive index is preferably 1.90 or less, more preferably 1.88 or less, still more preferably 1.85 or less, and still more preferably 1.83 or less.

Abbe number (. Nu.) of the optical glass of the present application _d ) The lower limit thereof is preferably 25.0, more preferably 25.5, and still more preferably 26.0. On the other hand, the Abbe number (. Nu.) of the optical glass of the present application _d ) The upper limit thereof is preferably 35.0, more preferably 34.0, and still more preferably 33.0.

As described above, the optical glass of the present application has the refractive index and abbe number, and can exhibit effects in optical design, and can be expected to have a high imaging property, and the like, and also to be miniaturized, and can be increased in the degree of freedom in optical design.

Here, the optical glass of the present application has a refractive index (n _d ) Abbe number (v) _d ) Preferably meets (-0.01Xv) _d +2.03)≤n _d ≤(-0.01×ν _d +2.13). Glass of specific composition according to the present application, refractive index (n _d ) Abbe number (v) _d ) Satisfying this relationship, stable glass can be obtained.

Therefore, the optical glass of the present application has a refractive index (n _d ) Abbe number (v) _d ) Preferably satisfy n _d ≥(-0.01×ν _d +2.03), further preferably satisfying n _d ≥(-0.01×ν _d +2.05).

On the other hand, the optical glass of the present application has a refractive index (n _d ) Abbe number (v) _d ) Preferably satisfy n _d ≤(-0.01×ν _d +2.13), further preferably satisfying n _d ≤(-0.01×ν _d +2.10).

The optical glass has lower partial dispersion ratio (thetag, F).

More specifically, the optical glass of the present application has a partial dispersion ratio (θg, F) and an abbe number (v) _d ) Preferably (-0.00162 Xv) _d +0.620)≤(θg，F)≤(-0.00162×ν _d +0.657).

Therefore, the optical glass of the present application has a partial dispersion ratio (θg, F) and an Abbe number (v) _d ) Preferably satisfies thetag, F is not less than (-0.00162 Xv) _d +0.620), further preferably θg, F.gtoreq (-0.00162 Xv) _d +0.630).

On the other hand, the optical glass of the present application has a partial dispersion ratio (θg, F) and an Abbe number (v) _d ) Preferably satisfies thetag, F is less than or equal to (-0.00162 Xv) _d +0.657), further preferably satisfying θg, F.ltoreq.(-0.00162×ν _d +0.650).

Thus, an optical glass having a low partial dispersion ratio (θg, F) can be obtained, and an optical element formed of the optical glass can be effective in reducing chromatic aberration of an optical system.

Furthermore, in particular at Abbe number (. Nu. _d ) In the smaller region, the value of the partial dispersion ratio (thetag, F) of the glass is higher than that of the normal line, and the Abbe number (v) is taken as the transverse axis _d ) When the vertical axis is the partial dispersion ratio (θg, F), the partial dispersion ratio (θg, F) and Abbe number (v) of the glass are generally _d ) The relationship of (2) is shown by a curve having a larger inclination than the normal line. The above-mentioned partial dispersion ratio (thetag, F) and Abbe number (v) _d ) In the relational expression (a), it is shown that by defining the relationship between the straight lines having a larger gradient than the normal line, a glass having a smaller partial dispersion ratio (θg, F) than that of a general glass can be obtained.

In the optical glass of the present application, the temperature coefficient of relative refractive index (dn/dT) is low.

More specifically, the upper limit of the temperature coefficient of the relative refractive index of the optical glass of the present application is preferably +6.0X10 ^-6 ℃ ^-1 More preferably +5.5X10 ^-6 ℃ ^-1 More preferably +5.0X10) ^-6 ℃ ^-1 And may take the upper limit value or a lower (negative side) value than the upper limit value.

On the other hand, the temperature coefficient of the relative refractive index of the optical glass of the present application is preferably-5.0X10 ^-6 ℃ ^-1 Further preferably-1.0X10 ^-6 ℃ ^-1 More preferably-0.5X10 ^-6 ℃ ^-1 And the lower limit value or a value higher (positive value side) than the lower limit value may be taken.

Wherein the refractive index (n) _d ) And has an Abbe number (v) of 25 to 35 _d ) Among the glasses of (a), a glass having a low temperature coefficient of relative refractive index is not so common, and thus, the selection of correction of the imaging defocus and the like due to the temperature change becomes large, and the correction can be more easily performed. Thus, by doubling upThe temperature coefficient of the emissivity is set to the above range, and can contribute to correction of imaging defocus or the like due to temperature change.

The temperature coefficient of the relative refractive index of the optical glass of the present application means the temperature coefficient of the refractive index (589.29 nm) in air at the same temperature as that of the optical glass, and the temperature is changed from 40℃to 60℃by the amount of change (. Degree.C.) corresponding to each 1℃ ^-1 ) To represent.

The optical glass of the present application preferably has an average linear thermal expansion coefficient α of 80 (10) ^-7 ℃ ^-1 ) The above. That is, the optical glass of the present application preferably has an average linear thermal expansion coefficient α at 100 to 300℃of 80 (10) ^-7 ℃ ^-1 ) Above, more preferably 85 (10) ^-7 ℃ ^-1 ) The above, more preferably 90 (10) ^-7 ℃ ^-1 ) The above.

In general, since breakage is likely to occur when the average linear thermal expansion coefficient α is large during glass processing, it is desirable that the average linear thermal expansion coefficient α be small. On the other hand, from the viewpoint of joining with a glass material having a low temperature coefficient of relative refractive index and a large average linear thermal expansion coefficient α, it is desirable that the value of the average linear thermal expansion coefficient α is the same as or similar to that of the glass material.

Wherein the refractive index (n) _d ) And has an Abbe number (v) of 25 to 35 _d ) Among the glasses of (a), a glass material having a large average linear thermal expansion coefficient α is less, and when used in combination with a glass material having a low refractive index and low dispersion, the average linear thermal expansion coefficient α as shown in the present application is more useful as a large value.

The optical glass of the present application desirably has a small specific gravity. More specifically, the specific gravity of the optical glass of the present application is preferably 5.00 (g/cm ³ ) The following is given. This reduces the mass of the optical element and the optical device using the optical element, and contributes to the weight reduction of the optical device.

Therefore, the specific gravity of the optical glass of the present application is preferably 5.00, more preferably 4.70, and still more preferably 4.50. The specific gravity of the optical glass of the present application is usually about 2.80 or more, more specifically 2.90 or more, and still more specifically 3.00 or more.

The specific gravity of the optical glass of the present application is measured according to the Japanese optical glass industry Condition standard JOGIS05-1975 "method for measuring specific gravity of optical glass".

Preformed section bar and optical element

The glass molded body can be produced from the produced optical glass by a press molding method such as hot press molding or precision press molding. That is, a preform for press molding can be produced from an optical glass, and the preform can be subjected to hot press molding and then polishing to produce a glass molded article; or a preform produced by polishing is subjected to precision press molding to produce a glass molded body or the like. The method for producing the glass molded product is not limited to the above method.

The glass molded article produced as described above can be suitably used for various optical elements, and the use thereof is particularly preferable for optical elements such as lenses and prisms. Thus, the color bleeding due to chromatic aberration can be reduced for the transmitted light of the optical system provided with the optical element. Therefore, when the optical element is used in a camera, the object to be photographed can be expressed more accurately, and when the optical element is used in a projector, a desired image can be projected with higher sharpness.

Examples

Compositions of examples (No. 1 to No. 12) and comparative examples of the present application and refractive index (n) _d ) Abbe number (v) _d ) The results of the partial dispersion ratio (. Theta.g, F), the temperature coefficient of relative refractive index (dn/dT), the average linear thermal expansion coefficient (100-300 ℃ C.), and the specific gravity are shown in tables 1 to 2. Furthermore, the following examples are for illustrative purposes only, and the present application is not limited to these examples.

The glasses of examples and comparative examples of the present application were prepared by selecting raw materials of high purity used for general optical glasses such as oxides, hydroxides, carbonates, nitrates, fluorides, metaphosphoric acid compounds, etc. corresponding to the raw materials, weighing the raw materials in the composition ratios of examples and comparative examples shown in the table, mixing the raw materials uniformly, charging the raw materials into a stone crucible (a platinum crucible or an alumina crucible may be used depending on the melting property of the glass), melting the raw materials in an electric furnace at a temperature of 1100 to 1400 ℃ for 0.5 to 5 hours, stirring the raw materials uniformly in the platinum crucible, defoaming the raw materials, cooling the raw materials to 1000 to 1200 ℃, stirring the raw materials again, casting the raw materials in a mold, and cooling the raw materials slowly.

Refractive index (n) of glass of examples and comparative examples _d ) Abbe number (v) _d ) And the partial dispersion ratio (thetag, F) was measured according to JOGIS01-2003, a Japanese optical glass industry standard.

The temperature coefficient of relative refractive index (dn/dT) of the glasses of examples and comparative examples was measured at a wavelength of 589.29nm according to the interferometry method described in JOGIS18-2008 "method for measuring temperature coefficient of refractive index of optical glass", which is a Japanese optical glass Industrial Condition standard.

The average linear thermal expansion coefficients (100 to 300 ℃) of the glasses of examples and comparative examples were obtained from a thermal expansion curve obtained by measuring the relationship between the temperature and the elongation of the sample in accordance with the "method for measuring thermal expansion of optical glass" of the japanese optical glass industry standard JOGIS 08-2003.

The specific gravity of the glass of examples and comparative examples was measured according to the Japanese optical glass industry Condition standard JOGIS05-1975 "method for measuring specific gravity of optical glass".

[ Table 1 ]

[ Table 2 ]

Embodiments of the applicationAn optical glass of (c) having a refractive index (n _d ) Is 1.70 or more, more specifically 1.72 or more, and the refractive index (n _d ) 1.90 or less, more specifically 1.88 or less, are within the desired range.

In addition, the optical glass of the embodiment of the application has Abbe number (v _d ) 25 or more, more specifically 26 or more, and the Abbe number (v) _d ) 35 or less, is within a desired range.

As shown in the tables, the optical glass according to the embodiment of the present application has the partial dispersion ratio (. Theta.g, F) and Abbe number (. Nu.) _d ) Satisfies (-0.00162 Xv) _d +0.620)≤(θg，F)≤(-0.00162×ν _d +0.657), and in more detail satisfies (-0.00162×ν) _d +0.630)≤(θg，F)≤(-0.00162×ν _d +0.650). That is, the glass of the embodiment of the present application has a partial dispersion ratio (θg, F) and Abbe number (v) _d ) The relationship between these results is shown in FIG. 2.

On the other hand, the optical glass of the comparative example did not satisfy (-0.00162 Xv) _d +0.620)≤(θg，F)≤(-0.00162×ν _d +0.657).

Furthermore, the optical glass of the embodiment of the present application has refractive index (n _d ) Abbe number (v) _d ) Satisfies (-0.01 Xv) _d +2.03)≤n _d ≤(-0.01×ν _d +2.13), more specifically (-0.01Xv) _d +2.05)≤n _d ≤(-0.01×ν _d +2.10). That is, regarding the refractive index (n _d ) Abbe number (v) _d ) The relationship between these is shown in FIG. 3.

As shown in the table, the optical glasses of examples have temperature coefficients of relative refractive indexes of +6.0X10 ^-6 ～-0.5×10 ^-6 (℃ ^-1 ) Is within a desired range.

The optical glass of the present application has an average linear thermal expansion coefficient α of 80 (10) ^-7 ℃ ^-1 ) The above.

In addition, the specific gravity of the optical glass of the embodiment of the application is below 5.00. Therefore, it is clear that the specific gravity of the optical glass of the embodiment of the present application is small.

Further, the optical glass according to the embodiment of the present application is used to form a glass block, and the glass block is ground and polished to form a lens or prism shape. As a result, various lens and prism shapes can be stably processed.

While the application has been described in detail and with reference to the embodiments thereof, it will be understood by those skilled in the art that the foregoing is illustrative only and that various changes in form and detail may be made therein without departing from the spirit and scope of the application.

Claims

1. An optical glass comprising, in mass%, siO ₂ 20.0 to 33.03 percent of components, nb ₂ O ₅ Components 41.90 to 44.94 percent, zrO ₂ 4.57 to 15.0 percent of components and TiO ₂ 0 to 2.85 percent of component B ₂ O ₃ The component (A) is below 2.78%, and the mass sum (TiO) ₂ +Nb ₂ O ₅ +ZrO ₂ ) 49.02% or more and less than 60.0% by mass (Li ₂ O/Na ₂ O+K ₂ O) is between 0.40 and 1.00, rn ₂ Mass sum of O component and Nb ₂ O ₅ Mass ratio of the components (Rn ₂ O/Nb ₂ O ₅ ) Is 0.37 or less, wherein Rn is at least one selected from the group consisting of Li, na, K, and the mass ratio (SiO ₂ /Nb ₂ O ₅ ) A refractive index (n) of 0.75 or less _d ) An Abbe number (. Nu.) of 1.76 or more _d ) A partial dispersion ratio (thetag, F) and Abbe number (v) of 30.06 or less _d ) Satisfies (-0.00162 Xv) _d +0.620)≤(θg，F)≤(-0.00162×ν _d The relation of +0.657) and the temperature coefficient (40-60 ℃) of the relative refractive index (589.29 nm) is +6.0X10 ^-6 ～-5.0×10 ^-6 (℃ ^-1 ) Within a range of (2).

2. The optical glass according to claim 1, wherein,

refractive index (n) _d ) Abbe number (v) _d ) Meets (-0.01 Xv) _d +2.03)≤n _d ≤(-0.01×ν _d +2.13).

3. A preform comprising the optical glass of claim 1 or 2.

4. An optical element comprising the optical glass of claim 1 or 2.

5. An optical instrument comprising the optical element according to claim 4.