CN110642512A

CN110642512A - Optical glass, prefabricated member and optical element

Info

Publication number: CN110642512A
Application number: CN201911087187.2A
Authority: CN
Inventors: 松石早矢
Original assignee: Ohara Inc
Current assignee: Ohara Inc
Priority date: 2015-02-20
Filing date: 2016-02-18
Publication date: 2020-01-03
Also published as: CN105906198A

Abstract

The invention aims to provide optical glass with high refractive index, low dispersion and high stability, and a prefabricated member and an optical element made of the optical glass. The optical glass contains B in mass% based on oxide₂O₃Composition (I)8.0～40.0％，Ln₂O₃15.0 to 80.0%, wherein Ln is at least 1 selected from the group consisting of La, Gd, Y and Yb, and the composition contains 5.0 to 50.0% by mass of an F component based on the mass of an oxide other than the F component, and has a refractive index n of 1.50 to 1.80_dAnd an Abbe number v of 45 to 65_d。

Description

Optical glass, prefabricated member and optical element

Technical Field

The invention relates to an optical glass, a prefabricated member and an optical element.

Background

In recent years, the digitalization and high definition of devices using optical systems have been rapidly advancing, and in the field of various optical devices such as photographic equipment such as digital cameras and video cameras, and video playback (projection) equipment such as projectors and projection televisions, there has been an increasing demand for reducing the number of optical elements such as lenses and prisms used in optical systems, and for reducing the weight and size of the entire optical system.

In the optical glass for manufacturing optical elements, the optical glass has a high refractive index (n) of 1.50-1.80, particularly, which can realize the light weight and the miniaturization of the whole optical system_d) And high Abbe number (v)_d) The demand for high refractive index low dispersion glass becomes very high. In this regard, glass components represented by patent documents 1 to 3 are widely known.

[ patent document 1 ] Japanese patent document laid-open No. 2013-063888

[ patent document 2 ] Japanese patent laid-open No. 2012-126586

[ patent document 3 ] International publication No. 2010/090014 of Japanese patent document

Technical problem to be solved by the invention

However, the glasses described in patent documents 1 to 3 have problems of a small abbe number and insufficient stability of the glass. Therefore, it is required to have a high refractive index (n) of 1.50 to 1.80_d) And a higher abbe number (low dispersion) optical glass. In addition, stable optical glass having not only a high refractive index and a low dispersion is also required.

On the other hand, in the correction of aberration (secondary spectrum) in the blue region among chromatic aberration, a partial dispersion ratio (θ g, F) is used as an index of optical characteristics which are attracting attention in optical design. The partial dispersion ratio (θ g, F) is represented by the following formula (1).

θg，F＝(n_g－n_F)/(n_F－n_C)······(1)

Here, in an optical system that performs chromatic aberration correction by combining a low-dispersion convex lens and a high-dispersion concave lens, an optical material having a large partial dispersion ratio (θ g, F) is used in the low-dispersion side lens, and an optical material having a small partial dispersion ratio (θ g, F) is used in the high-dispersion side lens, and by combining them, the secondary spectrum can be corrected.

However, the glasses described in patent documents 1 to 3 have a small partial dispersion ratio even with a high refractive index and a low dispersion, and are not sufficient for use as lenses for correcting secondary spectra. That is, it is required to have not only a high refractive index (n)_d) And a higher Abbe number (v)_d) And an optical glass having a large partial dispersion ratio (θ g, F).

The present invention has been made in view of the above problems, and an object thereof is to provide an optical glass having a high refractive index and a low dispersion and high stability, and a preform and an optical element manufactured using the same.

In addition, an object of the present invention is to provide an optical glass having a high refractive index and a low dispersion and preferably usable for chromatic aberration correction, and a preform and an optical element manufactured using the same.

Disclosure of Invention

The present inventors, in order to solve the above problems, have conducted extensive experiments and studies, and as a result, they have conducted B₂O₃Component (b) and Ln₂O₃The present inventors have found that the use of an F component in the components (where Ln is 1 or more selected from the group consisting of La, Gd, Y and Yb) together with the adjustment of the content of each component not only achieves a high refractive index and a low dispersion of the glass but also improves the stability of the glass, and have completed the present invention.

In addition, the present inventors have found that SiO₂Component (B)₂O₃Component (Ln)₂O₃The component (Ln is more than 1 selected from the group consisting of La, Gd, Y and Yb) and BaO component are simultaneously used as F component, and the content of each component is adjustedIt has been found that the glass has improved stability while achieving a high refractive index and low dispersion.

Further, the present inventors have found that the partial dispersion ratio of glass is further improved while achieving a high refractive index and a low dispersion by adjusting the content of each component.

Specifically, the present invention provides the following optical glasses.

(1) An optical glass characterized by containing B in mass% on an oxide basis₂O₃8.0 to 40.0% of component (Ln)₂O₃15.0 to 80.0% of a component (b), wherein Ln is at least 1 selected from the group consisting of La, Gd, Y and Yb,

contains 5.0 to 50.0% by mass of the F component based on the oxide other than the F component, and has a refractive index n of 1.50 to 1.80_dAnd an Abbe number v of 45 to 65_d。

(2) The optical glass according to the above (1), wherein Ln is contained in an amount of mass% based on an oxide₂O₃A component (b) of 25.0 to 80.0%, wherein Ln is at least 1 selected from the group consisting of La, Gd, Y and Yb, and has a refractive index n of at least 1.65 and at most 1.80_d。

(3) The optical glass according to the above (1) or (2), wherein the glass composition further comprises, in mass% on an oxide basis,

SiO₂the component(s) is (are) 0 to 20.0%,

BaO content is 0-35.0%.

(4) The optical glass according to the above (1), characterized by containing SiO in a mass% based on an oxide₂1.0 to 20.0% of component B₂O₃10.0 to 40.0% of component (Ln)₂O₃15.0 to 60.0% of a component and 5.0 to 55.0% of a BaO component, wherein Ln is at least 1 selected from the group consisting of La, Gd, Y and Yb,

contains 5.0 to 40.0% by mass of the F component calculated by mass% based on the oxide other than the F component,

has a refractive index n of 1.50 to 1.74_dAnd an Abbe number v of 45 to 65_d。

(5) The optical glass according to any one of the above (1) to (4), wherein the glass is characterized in that, as calculated by mass% based on an oxide,

La₂O₃the component is 0-60.0%,

Gd₂O₃the component is 0-30.0%,

Y₂O₃the component(s) is (are) 0 to 20.0%,

Yb₂O₃the component(s) is (are) 0 to 20.0%,

TiO₂the component(s) is (are) 0 to 20.0%,

Nb₂O₅the component(s) is (are) 0 to 20.0%,

WO₃the component is 0-15.0%,

Bi₂O₃the component(s) is (are) 0 to 20.0%,

MgO component of 0 to 10.0%,

CaO component is 0-20.0%,

0 to 25.0% of SrO,

Li

₂0 to 10.0% of an O component,

Na₂0 to 10.0% of an O component,

K

₂0 to 10.0% of an O component,

0 to 20.0 percent of ZnO,

P₂O₅the component(s) is (are) 0 to 10.0%,

GeO₂the component(s) is (are) 0 to 10.0%,

Ta₂O₅the component(s) is (are) 0 to 20.0%,

ZrO₂the component(s) is (are) 0 to 20.0%,

Al₂O₃the component(s) is (are) 0 to 20.0%,

Ga₂O₃the component(s) is (are) 0 to 20.0%,

TeO₂the component(s) is (are) 0 to 20.0%,

SnO

₂0 to 5.0% of a component, and

Sb₂O₃the component is 0-1.0%.

(6) The optical glass according to any one of the above (1) to (5), wherein the oxide-based mass ratio F/Ln₂O₃Is 0.05 to 1.00, where Ln₂O₃The content of the component is a content calculated as mass% based on oxides, and the content of the F component is a content calculated as mass% with respect to the mass based on oxides other than the F component.

(7) The optical glass according to any one of the above (1) to (6), characterized in that the sum of the oxide-based masses (SiO)₂+B₂O₃) 15.0% to 50.0%.

(8) The optical glass according to any one of the above (1) to (7), wherein the oxide-based mass ratio (SiO)₂+B₂O₃) Has a/F of 0.50 to 5.00, where SiO is₂Component (A) and (B)₂O₃The content of the component is a content calculated as mass% based on oxides, and the content of the component F is a content calculated as mass% based on oxides other than the component F.

(9) The optical glass according to any one of the above (1) to (8), wherein the oxide-based mass ratio Ln₂O₃/(SiO₂+B₂O₃) Is 0.50 or more, wherein Ln is 1 or more selected from the group consisting of La, Gd, Y and Yb.

(10) The optical glass according to any one of the above (1) to (9), wherein the oxide-based mass ratio (TiO)₂+Nb₂O₅+WO₃+Bi₂O₃) Has a/F of 0.50 or less, wherein TiO is used₂Component (B) and Nb₂O₅Component (I) and WO₃Component (B) and Bi₂O₃The content of component (A) is a content calculated as mass% based on the oxide, and the content of component (F) is a content in mass% based on the oxide other than component (F)Calculated content.

(11) The optical glass according to any one of the above (1) to (10), wherein a sum of the mass of the RO components based on oxides is 60.0% or less, and R is 1 or more selected from the group consisting of Mg, Ca, Sr and Ba.

(12) The optical glass according to any one of the above (1) to (11), wherein an oxide-based mass ratio (BaO/RO) is 0.50 or more, and wherein R is 1 or more selected from the group consisting of Mg, Ca, Sr and Ba.

(13) The optical glass according to any one of the above (1) to (12), characterized in that the sum of the oxide-based masses (Ln)₂O₃+ BaO) is 30.0% to 85.0%, where Ln is 1 or more selected from the group consisting of La, Gd, Y and Yb.

(14) The optical glass according to any one of the above (1) to (13), wherein the oxide-based mass ratio (Ln)₂O₃+BaO)/(SiO₂+B₂O₃) Is 1.00 or more, wherein Ln is 1 or more selected from the group consisting of La, Gd, Y and Yb.

(15) The optical glass according to any one of the above (1) to (14), wherein Rn based on oxide is₂The sum of the mass of O components is 10.0% or less, and Rn is 1 or more selected from the group consisting of Li, Na and K.

(16) The optical glass according to any one of the above (1) to (15), characterized in that the sum of the oxide-based masses (Ta)₂O₅+ZrO₂+Al₂O₃) Is 20.0% or less.

(17) The optical glass according to any one of the above (1) to (16), wherein the refractive index n_dAnd Abbe number v_dSatisfy (-0.01 v)_d+2.15)≦n_d≦(-0.01ν_d+ 2.35).

(18) An optical element comprising the optical glass according to any one of the above (1) to (17).

(19) A preform which is composed of the optical glass described in any one of the above (1) to (17) and which is used for polishing and/or precision press molding.

(20) An optical element, characterized in that the preform of (19) above is subjected to precision press working.

Effects of the invention

According to the present invention, it is possible to provide an optical glass having a high refractive index and a low dispersion and having high stability, and a preform and an optical element made of the same.

In addition, according to the present invention, it is possible to provide an optical glass having a high refractive index and a low dispersion and preferably usable for chromatic aberration correction, and a preform and an optical element manufactured using the same.

Drawings

FIG. 1 shows Abbe number (. nu.g) with a partial dispersion ratio (. theta.g, F) as the y-axis_d) Is a standard line schematic diagram shown in a rectangular coordinate system of an x-axis.

FIG. 2 shows the refractive index (n) of a glass of an example of the first optical glass_d) And Abbe number (v)_d) Schematic diagram of the relationship of (1).

FIG. 3 shows the refractive index (n) of a glass of an example of the second optical glass_d) And Abbe number (v)_d) Schematic diagram of the relationship of (1).

FIG. 4 shows a partial dispersion ratio (. theta.g, F) and an Abbe number (. nu.d) of a glass of an example of the first optical glass_d) Schematic diagram of the relationship of (1).

FIG. 5 shows a partial dispersion ratio (. theta.g, F) and an Abbe number (. nu.d) of a glass of an example of the second optical glass_d) Schematic diagram of the relationship of (1).

Detailed Description

The optical glass of the present invention contains B in mass% based on oxides₂O₃8.0 to 40.0% of component(s), Ln₂O₃15.0-80.0% of component (Ln is more than 1 selected from the group consisting of La, Gd, Y and Yb) and is contained in mass% relative to the mass of oxide except the component F5.0% to 50.0% of F component, and has a refractive index (n) of 1.50 to 1.80_d) And an Abbe number (v) of 45 to 65_d)。

Wherein the first optical glass contains B in mass% based on oxide₂O₃8.0 to 40.0% of component(s), Ln₂O₃25.0 to 80.0% of a component (wherein Ln is at least 1 selected from the group consisting of La, Gd, Y and Yb), 5.0 to 50.0% of a component F, calculated as mass%, based on the mass of oxides other than the component F, and having a refractive index (n) of 1.65 to 1.80_d) And an Abbe number (v) of 45 to 65_d)。

The second optical glass contains SiO in a mass% based on the oxide₂1.0 to 20.0% of component B₂O₃10.0 to 40.0% of component(s), Ln₂O₃15.0 to 60.0% of a component (wherein Ln is at least 1 selected from the group consisting of La, Gd, Y and Yb) and 5.0 to 55.0% of a BaO component, and contains 5.0 to 40.0% by mass of the F component based on the oxide other than the F component, and has a refractive index (n) of 1.50 to 1.74 (the content of n is not less than 5.0% and not more than 40.0% by mass)_d) And an Abbe number (v) of 45 to 65_d)。

In B₂O₃Component (b) and Ln₂O₃The use of the component F in the composition and the adjustment of the content of each component can not only achieve a high refractive index and a low dispersion of the glass but also improve the stability of the glass. In particular, in the second optical glass, in SiO₂Component (B)₂O₃Component (Ln)₂O₃The composition and the BaO composition are both F-containing and the contents of the respective components are adjusted to achieve not only a high refractive index and a low dispersion but also an improvement in the stability of the glass. Therefore, it is possible to provide an optical glass having a high refractive index and a low dispersion and having a high stability, and a preform and an optical element made of the same.

Further, by adjusting the content of each component, not only can the high refractive index and the low dispersion be achieved, but also the partial dispersion ratio of the glass can be further improved.

Therefore, it is possible to provide an optical glass having a high refractive index and a low dispersion and preferably useful for chromatic aberration correction, and a preform and an optical element made using the same.

Hereinafter, embodiments of the optical glass of the present invention will be specifically described. The present invention is not limited to the following embodiments, and can be carried out with appropriate modifications within the intended scope of the present invention. Note that, although the description of the parts to be described repeatedly may be appropriately omitted, the gist of the invention is not limited thereto.

[ glass composition ]

The composition ranges of the respective components constituting the optical glass of the present invention are as follows. In the present specification, unless otherwise specified, the contents of each component are expressed in mass% with respect to the total mass of the glass in terms of oxides. Here, the "composition in terms of oxides" means the composition of each component contained in the glass, assuming that all of the oxides, complex salts, metal fluorides, and the like used as the raw materials of the glass composition components of the present invention are decomposed and converted into oxides during melting, assuming that the total mass of the oxides is 100 mass%.

< essential Components, optional Components >

B₂O₃The component (b) is an essential component which can promote the formation of stable glass and the improvement of devitrification resistance and can also improve the abbe number by forming a network structure in the glass when it is contained in an amount of 8.0% or more. Thus, B₂O₃The content of the component (B) is preferably 8.0% or less, more preferably 10.0% or less, still more preferably 11.0% or less, still more preferably 13.0% or less, still more preferably 14.0% or less, and still more preferably 16.0% or less.

On the other hand, by making B₂O₃The content of the component (C) is 40.0% or less, and the decrease of the refractive index and the chemical durability can be suppressedLow. Thus, B₂O₃The content of the component (B) is preferably 40.0% or more, more preferably 33.0% or more, still more preferably 28.0% or more, still more preferably 24.0% or more, still more preferably less than 22.0%, still more preferably less than 21.0%, and still more preferably less than 20.0%.

B₂O₃Component (C) as a raw material, H can be used₃BO₃、Na₂B₄O₇、Na₂B₄O₇·10H₂O、BPO₄And the like.

Ln₂O₃The sum (mass sum) of the contents of components (Ln is more than 1 selected from the group consisting of La, Gd, Y and Yb) is 15.0-80.0%.

In particular, by setting the sum of the above masses to 15.0% or more, the refractive index and abbe number of the glass can be increased, and therefore a glass having a high refractive index and low dispersion can be obtained relatively easily. In addition, coloring can be reduced accordingly. Thus, Ln₂O₃The sum of the contents of the components is preferably 15.0% by mass, more preferably 17.0% by mass, still more preferably 21.0% by mass, still more preferably 25.0% by mass, yet more preferably 26.0% by mass, yet more preferably 31.0% by mass, yet more preferably 34.0% by mass, yet more preferably 36.0% by mass, and yet more preferably 39.0% by mass. In particular, in the first optical glass, Ln₂O₃The sum of the contents of the components may be 42.0% by mass or more preferably 46.0% by mass or less.

On the other hand, the total mass is 80.0% or less, whereby the resistance to devitrification can be improved. Thus, Ln₂O₃The sum of the contents of the components is preferably 80.0% by mass or less, more preferably less than 78.0%, even more preferably less than 75.0%, and even more preferably less than 72.0%. In particular, in the second optical glass, Ln₂O₃The sum of the contents of the components by mass is preferably60.0% or less, more preferably less than 55.0%, still more preferably less than 53.0%, still more preferably less than 50.0%, and still more preferably 48.5% or less.

The component F is an essential component for increasing the partial dispersion ratio of the glass and lowering the glass transition temperature by containing 5.0% or more. In particular, by containing the F component, an optical glass having a high partial dispersion ratio and less coloring can be obtained. Therefore, the content of the component F is preferably 5.0% or more, more preferably 5.5% or more, still more preferably 6.0% or more, yet more preferably 6.5% or more, still more preferably 7.0% or more, and still more preferably 8.0% or more. In particular, the content of the F component in the first optical glass may be more than 10.0%, or 10.6% or more.

On the other hand, by setting the F component content to 50.0% or less, the increase in the specific gravity of the glass can be suppressed, and the glass can be made less susceptible to devitrification. Therefore, the content of the component F is preferably 50.0% or more, more preferably 45.0% or more, still more preferably 40.0% or more, still more preferably 35.0% or more, still more preferably 30.0% or more, still more preferably 29.0% or more, still more preferably 24.0% or more, still more preferably 20.0% or more, still more preferably 17.0% or more, still more preferably 12.0% or more, and still more preferably 11.0% or more.

Component F, ZrF can be used as a raw material₄、AlF₃、NaF、CaF₂、LaF₃And the like.

The content of the F component in the present specification is a content in which the mass of the F component (calculated as mass% relative to the mass of the oxide other than the F component) is expressed as mass% assuming that all cationic components constituting the glass are combined with oxygen which only balances out charges to form an oxide, the optical glass of the present invention is formed from the oxide, and the total mass of the glass formed from these oxides is taken as 100%.

SiO₂When the content of the component (b) exceeds 0%, the coloring of the glass can be reduced and the devitrification resistance can be improved. In particular, the second optical glass contains 1.0% or more of the essential components for obtaining these effects. Thus, SiO₂The content of the component (B) is preferably more than 0%, more preferably more than 0.5%, still more preferably 1.0% or more, still more preferably more than 1.0%, still more preferably more than 2.0%, still more preferably more than 3.0%, still more preferably more than 4.0%.

On the other hand, by using SiO₂The content of the component (C) is 20.0% or less, and SiO can be adjusted to₂The components are easy to melt in the molten glass, and high-temperature melting is avoided. SiO 2₂The content of the component (B) is preferably 20.0% or less, more preferably less than 17.0%, still more preferably less than 15.0%, still more preferably less than 13.0%, still more preferably less than 12.0%, still more preferably less than 11.0%, still more preferably less than 10.0%, still more preferably less than 8.0%, still more preferably less than 5.0%.

SiO₂Component (C), SiO can be used as a raw material₂、K₂SiF₆、Na₂SiF₆And the like.

The BaO component is an optional component which can improve not only the refractive index and devitrification resistance of the glass but also the meltability of the glass raw material when the content exceeds 0%. In particular, the second optical glass contains 5.0% or more of the essential components for obtaining these effects. Therefore, the content of the BaO component is preferably more than 0%, more preferably more than 1.5%, further preferably more than 2.5%, further preferably 5.0% or more, further preferably more than 5.0%, further preferably more than 12.0%. In particular, the content of the BaO component in the second optical glass is more preferably more than 16.0%, still more preferably more than 20.0%, and further preferably more than 22.5%.

On the other hand, when the content of the BaO component is 55.0% or less, the refractive index of the glass is less likely to decrease, and devitrification of the glass can be reduced. Therefore, the content of the BaO component is preferably 55.0% or less, more preferably 45.0% or less, even more preferably 40.0% or less, even more preferably 35.0% or less, and even more preferably 30.0% or less. In particular, the content of the BaO component in the second optical glass may be less than 25.0%, and more preferably less than 20.0%.

BaO component, BaCO as a raw material₃、Ba(NO₃)₂And the like.

La₂O₃The component (b) is an optional component which can increase the refractive index and abbe number of the glass and improve the visible light transmittance when the content exceeds 0%. Thus, La₂O₃The content of the component (B) is preferably more than 0%, more preferably more than 1.0%, still more preferably more than 5.0%, still more preferably more than 10.0%, still more preferably more than 17.0%, still more preferably more than 15.0%, still more preferably more than 22.0%, still more preferably more than 26.0%, still more preferably still more than 28.0%.

On the other hand, by making La₂O₃When the content of the component is 60.0% or less, the glass is hardly devitrified and the increase of the specific gravity of the glass can be suppressed. In addition, in particular by reducing La₂O₃The content of the component (A) can suppress a decrease in the partial dispersion ratio. Thus, La₂O₃The content of the component (B) is preferably 60.0% or less, more preferably less than 55.0%, still more preferably less than 52.0%, still more preferably less than 50.0%, yet more preferably less than 45.0%, still more preferably less than 40.0%, yet more preferably less than 38.0%, still more preferably less than 37.0%, and still more preferably less than 35.0%.

La₂O₃Component (A) La can be used as a raw material₂O₃、La(NO₃)₃·XH₂O (X is an arbitrary integer), and the like.

Gd₂O₃The component (b) is an optional component which can increase the refractive index and Abbe number of the glass when the content exceeds 0%. Thus, Gd₂O₃The content of the component (B) is preferably more than 0%, more preferably more than 1.0%, still more preferably more than 3.0%, and further preferably more than 5.0%.

On the other hand, by using Gd₂O₃When the content of the component (B) is 30.0% or less, the increase in specific gravity and the decrease in partial dispersion ratio of the glass can be suppressed, and devitrification can be suppressed. Thus, Gd₂O₃The content of the component (B) is preferably 30.0% or less, more preferably less than 25.0%, still more preferably 23.0% or less, still more preferably 20.0% or less, still more preferably less than 20.0%, still more preferably less than 17.0%, still more preferably less than 15.0%, still more preferably 13.0% or less, still more preferably less than 10.0%, still more preferably less than 9.0%.

Gd₂O₃Component (B) Gd may be used as a raw material₂O₃、GdF₃And the like.

Y₂O₃Component (B) and Yb₂O₃The component (b) is an optional component which can increase the refractive index and Abbe number of the glass when the content of at least any one of the components exceeds 0%. In particular, Y₂O₃The component (B) may be a component capable of reducing the specific gravity of the glass. Thus, Y₂O₃The content of the component (B) is preferably more than 0%, more preferably more than 1.0%, still more preferably more than 3.0%, and further preferably more than 5.0%.

On the other hand, by making Y₂O₃Component (B) or Yb₂O₃The content of the component (B) is 20.0% or less, and the stability of the glass can be improved. In addition, especially by making Yb₂O₃The content of the component (B) is 20.0% or less, and the glass hardly absorbs light at a longer wavelength (around a wavelength of 1000 nm), so that the glass can have improved resistance to infrared rays. Thus, Y₂O₃Component (B) and Yb₂O₃The content of at least one of the components is preferably 20.0% or less, more preferably less than 15.0%, even more preferably less than 12.0%, and even more preferably less than 10.0%. In particular Yb₂O₃The content of the component (C) may be less than 5.0% or less than 1.0%.

Y₂O₃Component (B) and Yb₂O₃Component (B) as a raw material, Y can be used₂O₃、YF₃、Yb₂O₃And the like.

TiO₂Component (B) and Nb₂O₅Component (B) and WO₃The component (b) is an optional component which can increase the refractive index and the partial dispersion ratio of the glass when the content of at least any one of the components exceeds 0%.

In particular, TiO₂Component (B) and Nb₂O₅Component (b), or a component capable of reducing specific gravity.

On the other hand, by reducing TiO₂Component (B) and Nb₂O₅Component (B) or WO₃The content of the component (a) can suppress a decrease in Abbe number and a decrease in light transmittance at a shorter wavelength (500nm or less) of visible light.

Thus, TiO₂The content of the component (B) is preferably 20.0% or less, more preferably less than 10.0%, even more preferably less than 5.0%, and even more preferably less than 3.0%.

In addition, Nb₂O₅The content of the component (B) is preferably 20.0% or less, more preferably 10.0% or less, still more preferably less than 10.0%, still more preferably less than 5.0%, still more preferably less than 3.0%, still more preferably less than 1.0%.

In addition, WO₃The content of the component (B) is preferably 15.0% or less, more preferably 10.0% or less, still more preferably less than 10.0%, still more preferably less than 5.0%, still more preferably less than 3.0%, still more preferably less than 1.0%.

TiO₂Component (B) and Nb₂O₅Component (A) and WO₃Component (C), TiO can be used as a raw material₂、Nb₂O₅、WO₃And the like.

Bi₂O₃The component (b) is an optional component which can increase the refractive index and the partial dispersion ratio of the glass when the content of at least any one of the components exceeds 0%. In addition, Bi₂O₃The component (B) may be a component capable of lowering the glass transition temperature.

On the other hand, by reducing Bi₂O₃The content of the component (a) can suppress a decrease in Abbe number and also suppress a decrease in transmittance of visible light at a shorter wavelength (500nm or less).

Thus, Bi₂O₃The content of the component (B) is preferably 20.0% or less, more preferably 10.0% or less, still more preferably less than 10.0%, still more preferably less than 5.0%, still more preferably less than 3.0%, still more preferably less than 1.0%.

Bi₂O₃Component (B) Bi can be used as a raw material₂O₃And the like.

The MgO component, CaO component and SrO component are optional components which improve the melting property of the glass and improve the devitrification resistance when the content of at least one of them exceeds 0%. In particular, in the second optical glass, the SrO component is also a component that can increase the refractive index of the glass.

On the other hand, by reducing the content of the MgO component, CaO component or SrO component, devitrification of the glass can be reduced. In particular, by reducing the content of the MgO component or CaO component, the decrease in refractive index can be suppressed. In particular, in the first optical glass, the decrease in refractive index can be suppressed by decreasing the content of the SrO component.

Therefore, the content of the MgO component is preferably 10.0% or less, more preferably less than 5.0%, even more preferably less than 3.0%, and even more preferably less than 1.0%.

The content of the CaO component is preferably 20.0% or less, more preferably 17.0% or less, still more preferably 10.0% or less, still more preferably less than 10.0%, still more preferably less than 5.0%, still more preferably less than 3.0%, and still more preferably less than 1.0%.

The content of the SrO component is preferably 25.0% or less, more preferably 18.0% or less, still more preferably less than 10.0%, and even more preferably less than 5.0%.

MgO component, CaO component and SrO component, MgCO can be used as the raw material₃、MgF₂、CaCO₃、CaF₂、Sr(NO₃)₂、SrF₂And the like.

Li₂O component and Na₂O component and K₂The O component is an optional component which can improve the meltability of the glass when the content of at least any one of the O components exceeds 0%.

Here, by making it contain Li₂And O component, a stable glass can be easily formed. Thus, especially in the second optical glass, Li is allowed to be present₂The content of the O component is preferably more than 0%, more preferably more than 1.0%, and still more preferably more than 1.5%.

In addition, K₂The O component is also a component which can further improve the partial dispersion ratio of the glass.

On the other hand, by reducing Li₂O component and Na₂O component or K₂The content of the O component can suppress the lowering of the refractive index of the glass and can reduce devitrification. In particular, by reducing Li₂The content of the O component can suppress the decrease in the partial dispersion ratio of the glass. Thus, Li₂O component and Na₂O and K₂The content of at least one of the O components is preferably 10.0% or less, more preferably less than 6.0%, even more preferably less than 5.0%, even more preferably less than 4.0%, even more preferably less than 3.0%. In particular, in the second optical glass, Na₂O and K₂The content of at least any one of the O components may be less than 1.0%.

Li₂O component and Na₂O component and K₂O component, Li being used as a raw material₂CO₃、LiNO₃、LiF、Na₂CO₃、NaNO₃、NaF、Na₂SiF₆、K₂CO₃、KNO₃、KF、KHF₂、K₂SiF₆And the like.

The ZnO component is an optional component which improves the meltability of the glass, lowers the glass transition temperature, and reduces devitrification when the content exceeds 0%.

On the other hand, by setting the content of the ZnO component to 20.0% or less, the decrease in refractive index and devitrification can be reduced. In addition, the viscosity of the molten glass can be increased, and thus the occurrence of glass streaks can be reduced. Therefore, the content of the ZnO component is preferably 20.0% or less, more preferably 10.0% or less, still more preferably less than 10.0%, even more preferably less than 5.0%, and even more preferably less than 2.0%.

ZnO component, ZnO or ZnF can be used as the raw material₂And the like.

P₂O₅When the content of the component (b) exceeds 0%, the liquidus temperature of the glass can be lowered to improve the resistance to devitrification.

On the other hand, by making P₂O₅When the content of the component (B) is 10.0% or less, the decrease in chemical durability, particularly the decrease in water resistance of the glass can be suppressed. Thus, P₂O₅The content of the component (B) is preferably 10.0% or less, more preferably less than 5.0%, even more preferably less than 3.0%, even more preferably less than 1.0%.

P₂O₅Component (B), Al (PO) can be used as a raw material₃)₃、Ca(PO₃)₂、Ba(PO₃)₂、BPO₄、H₃PO₄And the like.

GeO₂The component (b) is an optional component which can increase the refractive index of the glass and improve the devitrification resistance when the content exceeds 0%.

On the other hand, in the case of a liquid,due to GeO₂Since the raw materials for the components are expensive, the high content thereof increases the material cost, and thus the practicability of the obtained glass is lowered. Thus, GeO₂The content of the component (B) is preferably 10.0% or less, more preferably less than 5.0%, even more preferably less than 3.0%, even more preferably less than 1.0%.

GeO₂Ingredient GeO may be used as the raw material₂And the like.

Ta₂O₅When the content of the component (b) exceeds 0%, the refractive index and devitrification resistance of the glass can be improved.

On the other hand, by using Ta₂O₅When the content of the component (B) is 10.0% or less, the decrease in the partial dispersion ratio of the glass can be suppressed. In addition, by reducing the more expensive Ta₂O₅The components can suppress an increase in the material cost of the glass, and can reduce the manufacturing cost of the glass by avoiding high-temperature melting. Thus, Ta₂O₅The content of the component (B) is preferably 20.0%, more preferably 10.0%, still more preferably 5.0% or less, still more preferably less than 5.0%, still more preferably less than 3.0%, still more preferably less than 1.0%, and most preferably not contained.

Ta₂O₅Component (A) Ta can be used as a raw material₂O₅And the like.

ZrO₂When the content of the component (b) exceeds 0%, the refractive index and devitrification resistance of the glass can be improved.

On the other hand, by using ZrO₂When the content of the component (A) is 20.0% or less, the decrease in Abbe number can be suppressed and the decrease in partial dispersion ratio can be suppressed. In addition, since high-temperature melting of the glass raw material can be avoided, the manufacturing cost of glass can be reduced. Thus, ZrO₂The content of the component (B) is preferably 20.0% or less, more preferably less than 10.0%, even more preferably less than 5.0%, even more preferably less than 3.0%, even more preferably less than 2.5%.

ZrO₂Component (a) is prepared fromZrO may be used as a starting material₂、ZrF₄And the like.

Al₂O₃Component (A) and Ga₂O₃When the content of the component (b) exceeds 0%, a stable glass can be easily formed.

On the other hand, by using Al₂O₃Component (b) or Ga₂O₃The content of the component (B) is 20.0% or less, and the lowering of Abbe number can be suppressed. Thus, Al₂O₃Component (A) and Ga₂O₃The content of at least one of the components is preferably 20.0% or less, more preferably less than 10.0%, even more preferably less than 5.0%, even more preferably less than 3.0%, even more preferably less than 1.0%, and even more preferably 0.6% or less.

Al₂O₃Component (A) and Ga₂O₃Component (C), Al can be used as a raw material₂O₃、Al(OH)₃、AlF₃、Ga₂O₃、Ga(OH)₃And the like.

TeO₂The component (C) is an arbitrary component which can increase the refractive index and lower the glass transition temperature (Tg) when the content exceeds 0%.

TeO, on the other hand₂When a platinum crucible and a melting tank in which a portion in contact with molten glass is formed of platinum are used to melt glass raw materials, there is a problem that the raw materials can be alloyed with platinum. Thus, TeO₂The content of the component (B) is preferably 20.0% or less, more preferably less than 10.0%, even more preferably less than 5.0%, and even more preferably less than 3.0%.

TeO₂Component (C), TeO can be used as a raw material₂And the like.

SnO₂The component (b) is an optional component which can reduce the oxidation of the molten glass to clear the molten glass and can prevent the light transmittance of the glass from being lowered when the content exceeds 0%.

On the other hand, by reacting SnO₂The content of the component(s) is 5.0% or less, which enables the reduction of molten glass to be inducedColoration of the glass and devitrification of the glass hardly occur. In addition, SnO can be reduced₂The alloying of the components with the melting equipment (particularly noble metals such as Pt) makes it possible to achieve a longer service life of the melting equipment. Thus, SnO₂The content of the component (B) is preferably 5.0% or less, more preferably less than 3.0%, even more preferably less than 1.0%, even more preferably less than 0.5%.

SnO₂Component (C), SnO and SnO may be used as raw materials₂、SnF₂、SnF₄And the like.

Sb₂O₃The component (B) is an optional component which can defoam the molten glass when the content exceeds 0%.

On the other hand, by making Sb₂O₃The content of the component (c) is 1.0% or less, so that excessive foaming is not easily generated, and alloying with melting equipment (particularly, noble metal such as Pt) can be reduced. Thus, Sb₂O₃The content of the component (B) is preferably 1.0% or less, more preferably less than 0.5%, even more preferably less than 0.3%, and even more preferably less than 0.1%.

Sb₂O₃Component (C), Sb can be used as a raw material₂O₃、Sb₂O₅、Na₂H₂Sb₂O₇·5H₂O, and the like.

The component for clarifying and degassing the glass is not limited to Sb₂O₃As the component (b), a refining agent, a defoaming agent or a combination thereof, which are well known in the glass production field, may be used.

Ln calculated in% by mass on the basis of oxide₂O₃The total amount of the component (B) is preferably 0.05 to 1.00 in terms of the content of the component (F) in mass% based on the oxide-based mass excluding the component (F).

In particular, by setting the ratio to 0.05 or more, the partial dispersion ratio can be further improved. Therefore, the mass ratio F/Ln₂O₃Preferably, the water-soluble polymer is prepared byThe lower limit is 0.05, more preferably 0.07, still more preferably 0.09, and still more preferably 0.11.

On the other hand, by setting the ratio to 1.00 or less, the glass can be made less susceptible to devitrification. Therefore, the mass ratio F/Ln₂O₃Preferably 1.00 or less, more preferably less than 0.70, even more preferably less than 0.50, and even more preferably less than 0.30.

SiO₂Component (A) and (B)₂O₃The total amount (sum of mass) of the components is preferably 15.0% to 50.0%.

In particular, by setting the sum to 15.0% or more, stable glass can be formed relatively easily. Therefore, the sum of the masses (SiO)₂+B₂O₃) Preferably, it is 15.0% or more, more preferably, it is more than 18.0%, still more preferably, it is more than 21.0%, and still more preferably, it is more than 23.0%.

On the other hand, when the sum is 50.0% or less, the decrease in refractive index can be suppressed. Therefore, the sum of the masses (SiO)₂+B₂O₃) Preferably 50.0% or less, more preferably less than 43.0%, still more preferably less than 40.0%, still more preferably less than 35.0%, still more preferably less than 30.0%, and still more preferably less than 27.0%.

The content of the F component in mass% relative to the mass of the oxide other than the F component, and SiO in mass% based on the oxide₂Component (A) and (B)₂O₃The proportion of the total amount of the components is preferably 0.50 to 5.00.

In particular, when the ratio is 0.50 or more, the partial dispersion ratio of the glass can be increased and the glass transition temperature can be lowered. Therefore, the mass ratio (SiO)₂+B₂O₃) The lower limit of/F is preferably 0.50, more preferably 1.00, still more preferably 1.50, still more preferably 1.80, still more preferably 2.10, still more preferably 2.31The lower limit.

On the other hand, by setting the ratio to 5.00 or less, the glass can be made less susceptible to devitrification. In addition, the mass ratio (SiO)₂+B₂O₃) The ratio of/F is preferably 5.00 or less, more preferably less than 4.00, still more preferably less than 3.50, and still more preferably less than 3.00.

Relative to SiO₂Component (A) and (B)₂O₃Total amount of ingredients, Ln₂O₃The ratio (mass ratio) of the total amount of the components is preferably 0.50 or more. Accordingly, the refractive index and stability of the glass can be improved. Therefore, mass ratio Ln₂O₃/(SiO₂+B₂O₃) The lower limit is preferably 0.50, more preferably 1.00, still more preferably 1.30, still more preferably 1.50, and still more preferably 1.63.

In addition, mass ratio Ln₂O₃/(SiO₂+B₂O₃) The upper limit of (b) is at most substantially 8.00 or less, more specifically 6.00 or less, still more specifically 5.00 or less.

The content of the F component in mass% relative to the mass of the oxide other than the F component, and the TiO component in mass% relative to the mass of the oxide₂Component (B) and Nb₂O₅Component (I) and WO₃Component (B) and Bi₂O₃The proportion of the total amount of the components is preferably 0.50 or less. This can suppress a decrease in Abbe number. Therefore, the mass ratio (TiO)₂+Nb₂O₅+WO₃+Bi₂O₃) the/F is preferably 0.50, more preferably 0.45, still more preferably 0.40, still more preferably 0.35, and still more preferably 0.27.

The sum (sum of mass) of the contents of RO components (wherein R is at least one selected from the group consisting of Mg, Ca, Sr and Ba) is preferably 60.0% or less.

In particular, when the sum is 60.0% or less, devitrification due to an excessively high RO component content can be reduced and a decrease in refractive index can be suppressed. Therefore, the sum of the amounts by mass of the RO components is preferably 60.0% or less, more preferably less than 55.0%, even more preferably less than 45.0%, even more preferably 40.0% or less, even more preferably less than 35.0%, even more preferably less than 30.0%. In particular, the sum of the contents of the Ro components in the first optical glass may be less than 25.0% by mass, and more preferably less than 20.0% by mass.

On the other hand, when the sum is larger than 0%, the meltability of the glass raw material and the stability of the glass can be improved. In particular, in the second optical glass, these effects can be obtained by making the sum to be 5.0% or more. Therefore, the total content of the RO component is preferably more than 0%, more preferably more than 1.0%, still more preferably more than 3.0%, still more preferably more than 5.0%, and further more preferably more than 10.0%. In particular, the total content of the RO component in the second optical glass is preferably 5.0% or more, more preferably more than 10.0%, even more preferably more than 15.0%, even more preferably more than 20.0%, and even more preferably more than 23.0%.

The content ratio (mass ratio) of the BaO component to the sum of the contents of the RO components (in the formula, R is at least one selected from the group consisting of Mg, Ca, Sr, Ba) is preferably at least 0.50. Accordingly, a glass having a higher refractive index can be obtained relatively easily. Therefore, the mass ratio (BaO/RO) is preferably 0.50, more preferably 0.60, still more preferably 0.70, still more preferably 0.75, and still more preferably 0.85.

On the other hand, the upper limit of the ratio may be 1.00.

Ln₂O₃The sum (mass sum) of the total amount of the components (Ln is 1 or more selected from the group consisting of La, Gd, Y and Yb) and the BaO component content is preferably 30.0% or more and 85.0% or less.

In particular, when the sum is 30.0% or more, the sum can be further adjustedThe refractive index of the glass is increased. Thus, the sum of the masses (Ln)₂O₃+ BaO), preferably 30.0%, more preferably 45.0%, even more preferably 56.0%, even more preferably 60.0%, even more preferably 63.0%.

On the other hand, when the sum is 85.0% or less, the glass is less likely to devitrify. Thus, the sum of the masses (Ln)₂O₃+ BaO), preferably 85.0% or less, more preferably less than 83.0%, even more preferably less than 80.0%, and even more preferably less than 78.0%.

Relative to SiO₂Component (A) and (B)₂O₃Total amount of ingredients, Ln₂O₃The ratio (mass ratio) of the sum of the contents of the components (Ln is 1 or more selected from the group consisting of La, Gd, Y and Yb) and the BaO component is preferably 1.00 or more. Accordingly, the refractive index and stability of the glass can be improved. Therefore, mass ratio (Ln)₂O₃+BaO)/(SiO₂+B₂O₃) The lower limit is preferably 1.00, more preferably 1.30, still more preferably 1.50, still more preferably 1.70, still more preferably 2.00, still more preferably 2.50.

In addition, mass ratio (Ln)₂O₃+BaO)/(SiO₂+B₂O₃) The upper limit of (b) is at most substantially 8.00 or less, more specifically 6.00 or less, still more specifically 4.00 or less.

Rn₂The sum (mass sum) of the contents of O components (Rn is at least one selected from the group consisting of Li, Na and K in the formula) is preferably 10.0% or less. Accordingly, a decrease in the refractive index of the glass can be suppressed, and devitrification can also be reduced by improving the stability of the glass. Thus, Rn₂The total content of the O component is preferably 10.0% or less, more preferably less than 6.0%, even more preferably less than 5.0%, even more preferably less than 4.0%, even more preferably less than 3.0%.

On the other hand, in particular in the second optical glass, Rn₂The sum of the contents of the O components may be more than 0%. Accordingly, stable glass can be formed relatively easily. Thus, Rn₂The total content of the O component is preferably more than 0%, more preferably more than 1.0%, and further preferably more than 1.5%.

Ta₂O₅Component (C) ZrO₂Component (B) and Al₂O₃The sum of the contents (sum of mass) of the components is preferably 20.0% or less. Accordingly, the stability of the glass can be improved, and the decrease in the partial dispersion ratio can also be suppressed. Therefore, the sum of the masses (Ta)₂O₅+ZrO₂+Al₂O₃) The upper limit is preferably 20.0% or less, more preferably less than 10.0%, still more preferably less than 5.0%, still more preferably less than 2.5%, and still more preferably less than 1.5%.

< ingredients that should not be contained >

Next, components that should not be contained in the optical glass of the present invention and components that are preferable to be not contained will be described.

In the optical glass of the present invention, other components may be added as necessary within a range not to deteriorate the characteristics of the glass of the present invention. However, due to GeO₂The component (B) is preferably not contained in practice because it improves the dispersibility of the glass.

Further, each of the transition metal components other than Ti, Zr, Nb, W, La, Gd, Y, Yb, Lu, for example, Hf, V, Cr, Mn, Fe, Co, Ni, Cu, Ag, Mo, Ce, Nd, etc., has a characteristic that the glass is colored even when a small amount of each component is contained singly or in a mixture, and absorbs light of a specific wavelength in the visible region, and therefore, it is preferable that the glass is not substantially contained particularly in an optical glass using a wavelength in the visible region.

Further, lead compounds such As PbO and As₂O₃As arsenic compounds, such as Th, Cd, Tl, Os, Be and Se, and the like, have recently been used asThe harmful chemical substances tend to restrict their use, and environmental protection measures are required not only in the glass production process but also in the treatment process and the treatment after the product formation. Therefore, when importance is attached to the influence on the environment, it is preferable that these components are not substantially contained, except for inevitable mixing. Accordingly, the optical glass contains virtually no substances that contaminate the environment. Therefore, the optical glass can be manufactured, processed and discarded without taking special environmental protection measures.

[ production method ]

The optical glass of the present invention is produced, for example, as follows. That is, in order to uniformly mix the above-mentioned raw materials within a predetermined content range, the mixture produced is placed in a platinum crucible, a quartz crucible, or an alumina crucible and pre-melted, then placed in a gold crucible, a platinum alloy crucible, or an iridium crucible and melted at a temperature of 900 to 1400 ℃ for 1 to 5 hours, uniformly stirred and defoamed, and then the temperature is reduced to 1200 ℃ or less, and finally stirred to remove streaks, and then molded using a molding die. Here, as a method of obtaining glass molded by using a molding die, there are a method of drawing out the molded glass from one end of the molding die while flowing down molten glass to the other end of the molding die, and a method of injecting the molten glass into the die and slowly cooling it.

[ physical Properties ]

The optical glass of the present invention has a high refractive index and low dispersion (high Abbe number).

Refractive index (n) of the optical glass of the present invention_d) The lower limit is preferably 1.50, more preferably 1.55, still more preferably 1.60, and still more preferably 1.63. In particular, the refractive index (n) of the first optical glass_d) The lower limit is preferably 1.65, more preferably 1.66, and still more preferably 1.67.

Refractive index (n) of the optical glass of the present invention_d) The upper limit of (2) is preferablyIt is 1.80 or less, more preferably 1.77 or less, and still more preferably less than 1.74. In particular, the upper limit of the refractive index of the second optical glass is preferably 1.74 or less, more preferably 1.72 or less, further preferably 1.70 or less, and further preferably 1.67 or less.

Abbe number (v) of the optical glass of the present invention_d) Preferably 45 or more, more preferably 48 or more, still more preferably 50.5 or more, still more preferably 51 or more, yet more preferably more than 52, still more preferably 54 as a lower limit, yet more preferably 56 as a lower limit, and still more preferably 58 as a lower limit. Further, the Abbe number (. nu.) of the optical glass of the present invention_d) Preferably 65 or less, more preferably less than 64, still more preferably less than 63, and still more preferably less than 60.

The optical glass of the present invention has such a refractive index and abbe number, and is therefore useful for optical design, and in particular, not only can achieve high imaging characteristics and the like and downsizing of an optical system, but also can expand the degree of freedom of optical design.

Here, the optical glass of the present invention has a refractive index (n)_d) And Abbe number (v)_d) It is preferable that (-0.01 v) is satisfied_d+2.15)≦n_d≦(-0.01ν_d+ 2.25). The glass of the present invention has a specific composition such that the refractive index (n) is_d) And Abbe number (v)_d) By satisfying this relationship, a stable glass can be obtained.

Therefore, in the optical glass of the present invention, the refractive index (n)_d) And Abbe number (v)_d) It is preferable that n is satisfied_d≧(-0.01ν_d+2.15), more preferably n_d≧(-0.01ν_d+2.17), more preferably satisfies n_d≧(-0.01ν_d+2.20), more preferably n_d≧(-0.01ν_d+ 2.23).

On the other hand, in the optical glass of the present invention, the refractive index (n)_d) And Abbe number (v)_d) Is toIt is preferable that n is satisfied_d≦(-0.01ν_d+2.35), more preferably n_d≦(-0.01ν_d+2.32), more preferably satisfies n_d≦(-0.01ν_d+2.30), more preferably n_d≦(-0.01ν_d+2.29), more preferably satisfies n_d≦(-0.01ν_d+ 2.27).

The optical glass of the present invention preferably has a high partial dispersion ratio (θ g, F).

More specifically, the partial dispersion ratio (θ g, F) of the optical glass of the present invention is preferably 0.515 as a lower limit, more preferably 0.520 as a lower limit, still more preferably 0.525 as a lower limit, still more preferably 0.528 as a lower limit, and still more preferably 0.530 as a lower limit. On the other hand, the upper limit of the partial dispersion ratio (θ g, F) of the optical glass of the present invention is not particularly limited, but is preferably 0.630, more preferably 0.610, and still more preferably 0.570. In addition, the optical glass of the present invention has a partial dispersion ratio (θ g, F) and an Abbe number (. nu.)_d) In the relation (2), it is preferable that (θ g, F) ≧ 0.00162X v_d+ 0.6150).

As described above, the optical glass of the present invention has a higher partial dispersion ratio (θ g, F) than conventionally known glasses containing a large amount of rare earth elements. Therefore, an optical element formed of the optical glass can be preferably applied to correction of chromatic aberration while achieving high refractive index and low dispersion of the glass.

Here, the optical glass of the present invention has a partial dispersion ratio (. theta.g, F) and an Abbe number (. nu._d) In the relationship of (1), it is preferable that (-0.00162 x ν v)_d+0.6150) is the lower limit, more preferably (-0.00162 x ν)_d+0.6200) is the lower limit, and is more preferably (-0.00162 x ν)_d+0.6250) is the lower limit, more preferably (-0.00162 x ν)_d+0.6300) is the lower limit. On the other hand, the Abbe number (. nu.) of the optical glass of the present invention_d) Of partial dispersion ratios (θ g, F) in the relationship of (a)The upper limit is not particularly limited, but is at most approximately (-0.00162 x ν)_d+0.6800), more particularly (-0.00162 x ν)_d+0.6700), more specifically (-0.00162 x ν)_d+0.6600) or less. The glass of the present invention has a specific composition in which the partial dispersion ratio (. theta.g, F) and Abbe number (. nu._d) Satisfying this relationship, a more stable glass can be obtained.

The partial dispersion ratio (θ g, F) and Abbe number (v)_d) The relational expression (c) is expressed by using a straight line parallel to the standard line in a rectangular coordinate system in which the partial dispersion ratio is the y-axis and the abbe number is the x-axis. The standard line shows the partial dispersion ratio (. theta.g, F) and Abbe number (. nu.) of a glass which has been widely known in the prior art_d) Linear relationship between the partial dispersion ratio (theta g, F) and Abbe number (v)_d) In a rectangular coordinate system on the x-axis, the dispersion ratios and abbe numbers of NSL7 and PBM2 are represented by a straight line connecting two points (see fig. 1). The relationship between the partial dispersion ratio and the abbe number of the glass, which has been widely known in the related art, substantially overlaps with the standard line.

NSL7 and PBM2 are optical glasses manufactured by Mitsuki Kabushiki Kaisha, and the Abbe number (. nu.) of PBM2_d) 36.3, a partial dispersion ratio (. theta.g, F) of 0.5828, and an Abbe number (. nu.) of NSL7_d) 60.5, and the partial dispersion ratio (. theta.g, F) was 0.5436.

The optical glass of the present invention is preferably a glass having high resistance to devitrification (in the specification, it may be simply referred to as "devitrification resistance") in the production of a glass and being relatively stable. Accordingly, since a decrease in transmittance due to crystallization of the glass or the like can be suppressed in the production of the glass, the optical glass can be preferably applied to an optical element that transmits visible light, such as a lens. As a criterion indicating high devitrification resistance in manufacturing glass, for example, a low liquidus temperature may be mentioned.

[ preform and optical element ]

The glass molded body can be produced by a method of polishing or a method of press molding such as reheat press molding and precision press molding, for example, in addition to the produced optical glass. That is, the glass molded body can be produced by subjecting the optical glass to mechanical processing such as grinding and polishing, or by subjecting a preform produced from the optical glass to reheat press molding and then to polishing treatment, or by subjecting a preform produced by performing polishing treatment and a preform formed by float molding or the like, which is well known. The method for producing the glass shaped article is not limited to these methods.

Thus, the glass molded body made of the optical glass of the present invention is useful for various optical elements and optical designs, and is particularly preferably used for optical elements such as lenses and prisms. Since a glass molded body having a large diameter can be formed by improving the stability of glass, not only the optical element can be increased in size, but also high-definition and high-precision imaging characteristics and projection characteristics can be realized when the glass is used in optical instruments such as a camera and a projector.

In addition, by increasing the partial dispersion ratio, the optical element can be effectively applied to chromatic aberration correction of an optical system, and for example, in the case of applying the optical element to a camera, a photographed object can be accurately expressed, and in the case of applying the optical element to a projector, a desired image can be more delicately projected.

[ examples ] A method for producing a compound

Compositions of glasses of examples (No. A1 to No. A35, No. B1 to No. B11) of the present invention, and refractive indices (n) of these glasses_d) Abbe number (v)_d) And values of partial dispersion ratios (θ g, F) are shown in tables 1 to 7. Of these, examples (nos. a1 to 35) are examples of the first optical glass, and examples (nos. b1 to 11) are examples of the second optical glass. In addition, the following embodiments are always for the purpose of illustration, and are not limited to these embodiments.

The glasses of the examples were produced by selecting high-purity raw materials used for general optical glasses such as oxides, hydroxides, carbonates, nitrates, fluorides, hydroxides, metaphosphoric acid compounds, etc., which correspond to the raw materials of the respective components, weighing and uniformly mixing the raw materials, placing the mixture in a platinum crucible, heating the mixture in an electric furnace at 1250 to 1300 ℃ for 2 hours to melt the glass raw materials, stirring the molten glass raw materials to defoam the mixture, reducing the temperature to 900 to 1070 ℃, stirring the mixture again, pouring the mixture into a mold, and slowly cooling the mixture.

Here, when the glass raw material is melted to obtain glass, the F component and the B component₂O₃The volatilization of the components changes the composition of the glass raw materials and the composition of the resulting glass.

Concerning each component, the relationship between the composition of the glass raw material and the composition of the glass, particularly, B is contained₂O₃The content of the component (C) is 16% or more, and the content of the component (F) is 45.0% or less, the contents are approximately as follows.

B₂O₃The components: (content in glass) × 0.35 (content in glass raw material) +10.3 (mass%)

And F component: (content in glass) × 0.44 × (content in glass raw material) +1.39 (mass%)

Based on these numerical expressions, by mixing component F and component B₂O₃Component (B) and SiO₂The composition of the glass raw material can be determined by converting the content of the component in the glass into the content of the glass raw material and then converting the total content of the components into 100% with the content of the component F as the added content.

Refractive index (n) of glasses of examples_d) Abbe number (v)_d) And a partial dispersion ratio (. theta.g, F) measured according to JOGIS01-2003, a standard of Japan optical Nitri Industrial Association.

Furthermore, according to the measured refractive index (n)_d) And Abbe number (v)_d) Value of (D) in the relation n_d＝-a₁×ν_d+b₁In (1), the gradient a is obtained₁Intercept b at 0.01₁。

Furthermore, the Abbe number (. nu.) is determined according to the measured Abbe number_d) And the value of the partial dispersion ratio (theta g, F) is-a in the relation (theta g, F)₂×ν_d+b₂In (1), the gradient a is obtained₂At 0.001Intercept b at 62₂。

The glass used in the present measurement was treated with an annealing furnace at a slow cooling rate of-25 ℃/hr.

TABLE 1

TABLE 2

TABLE 3

TABLE 4

TABLE 5

TABLE 6

TABLE 7

As shown in the table, the refractive index (n) of the optical glass of the examples of the present invention_d) Is 1.50, more specifically 1.61 or more, and the refractive index (n)_d) Within the range of 1.80 or less, more specifically 1.76 or less, is preferred. In particular, in the embodiment of the first optical glass, the refractive index (n)_d) All are above 1.65. In addition, in the second lightIn the glasses of the examples of the optical glass, the refractive index (n)_d) Below 1.74, more particularly below 1.65.

In addition, the optical glass of the embodiment of the present invention has Abbe number (. nu.)_d) Above 45 and the Abbe number (v)_d) Below 65, more specifically below 63, are within the claimed ranges. In particular, in the embodiment of the first optical glass, Abbe number (. nu.)_d) Are all below 60. Further, in the examples of the second optical glass, Abbe number (. nu.)_d) Is above 59.

In addition, the optical glass of the embodiment of the present invention has a refractive index (n)_d) And Abbe number (v)_d) Satisfy (-0.01 v)_d+2.15)≦n_d≦(-0.01ν_d+ 2.35). In particular, in the embodiment of the first optical glass, the refractive index (n)_d) And Abbe number (v)_d) Satisfy (-0.01 v)_d+2.20)≦n_d≦(-0.01ν_d+ 2.29). In addition, in the embodiment of the second optical glass, the refractive index (n)_d) And Abbe number (v)_d) Satisfy (-0.01 v)_d+2.24)≦n_d≦(-0.01ν_d+ 2.28).

Further, the refractive index (n) of the glass of the example of the first optical glass_d) And Abbe number (v)_d) The relationship of (c) is as shown in FIG. 2. In addition, the refractive index (n) of the glass of the example of the second optical glass_d) And Abbe number (v)_d) The relationship of (c) is as shown in FIG. 3.

These optical glasses are stable glasses which are not devitrified.

Therefore, it is clear that the refractive index (n) of the optical glass of the examples of the present invention_d) And Abbe number (v)_d) All of them are within the required range, and an optical glass having high stability can be obtained.

The optical glass according to the embodiment of the present invention has a partial dispersion ratio (θ g, F) of 0.515 or more and a high value. In particular, in the embodiment of the first optical glass, the partial dispersion ratio (θ g, F) thereof is 0.520 or more, more specifically 0.525 or more. In addition, in the example of the second optical glass, the partial dispersion ratio (θ g, F) was 0.533 or more.

In addition, the optical glass of the embodiment of the present invention has a partial dispersion ratio (θ g, F) and an Abbe number (v)_d) Satisfy (theta g, F) ≧ 0.00162 x v_d+0.6150), more specifically (θ g, F) ≧ 0.00162 × ν_d+ 0.6160). In particular, in the examples of the second optical glass, the composition satisfies (θ g, F) ≧ 0.00162X ν_d+ 0.6280).

Further, the glass of the example of the first optical glass had a partial dispersion ratio (θ g, F) and an Abbe number (v)_d) The relationship of (2) is shown in FIG. 4. Further, the glass of the example of the second optical glass had a partial dispersion ratio (θ g, F) and an Abbe number (v)_d) The relationship of (2) is shown in FIG. 5.

As described above, the optical glass according to the embodiment of the present invention has a large partial dispersion ratio (θ g, F), and it is apparent that the optical element obtained from the optical glass can effectively correct chromatic aberration.

Therefore, the optical glass of the embodiment of the present invention has high refractive index and low dispersion, has high stability, and can be obviously and preferably applied to the correction of chromatic aberration.

Further, the optical glass obtained according to the example of the present invention was subjected to reheat press molding, and then ground and polished to be processed into the shapes of lenses and prisms. Further, using the optical glass of the embodiment of the present invention, a precision press-molding preform is formed, and precision press-molding is performed on the precision press-molding preform. In any case, the glass after heat softening does not have problems such as opalescence and devitrification, and can be stably processed into various shapes of lenses and prisms.

Although the present invention has been specifically described above for the purpose of example, the present embodiment is always for the purpose of example only. It is to be understood that various changes may be made by those skilled in the art without departing from the spirit and scope of the invention.

Claims

1. An optical glass characterized by containing SiO in a mass% on an oxide basis₂1.0 to 20.0% of component B₂O₃10.0 to 40.0% of component (Ln)₂O₃15.0 to 60.0% of a component and 5.0 to 55.0% of a BaO component, wherein Ln is at least 1 selected from the group consisting of La, Gd, Y and Yb,

has a refractive index n of 1.50 to 1.74_dAnd an Abbe number v of 45 to 65_d。

2. The optical glass according to claim 1, wherein the glass composition is characterized in that, in mass% on an oxide basis,

La₂O₃the component is 0-40.0%,

Gd₂O₃the component(s) is (are) 0 to 20.0%,

Y₂O₃the component(s) is (are) 0 to 20.0%,

Li₂the content of O is0 to 10.0%.

3. The optical glass according to claim 1 or 2, wherein the glass is characterized in that the glass is a glass having a refractive index calculated as mass% on an oxide basis,

MgO component of 0 to 10.0%,

CaO component is 0-20.0%,

0 to 25.0% of SrO,

Na₂0 to 10.0% of an O component,

K₂0 to 10.0% of an O component,

Yb₂O₃the component(s) is (are) 0 to 20.0%,

TiO₂the component(s) is (are) 0 to 20.0%,

Nb₂O₅the component(s) is (are) 0 to 20.0%,

WO₃the component is 0-15.0%,

P₂O₅the component(s) is (are) 0 to 10.0%,

GeO₂the component(s) is (are) 0 to 10.0%,

0 to 20.0 percent of ZnO,

ZrO₂the component(s) is (are) 0 to 20.0%,

Ta₂O₅the component(s) is (are) 0 to 20.0%,

Al₂O₃the component(s) is (are) 0 to 20.0%,

Ga₂O₃the component(s) is (are) 0 to 20.0%,

TeO₂the component(s) is (are) 0 to 20.0%,

Bi₂O₃the component(s) is (are) 0 to 20.0%,

SnO₂0 to 5.0% of a component, and

Sb₂O₃the component is 0-1.0%.

4. Optical glass according to any of claims 1 to 3, characterised in that the sum of the oxide-based masses (SiO)₂+B₂O₃) 15.0% to 50.0%.

5. Optical glass according to any of claims 1 to 4, characterised in that the oxide-based mass ratio (Ln)₂O₃+BaO)/(SiO₂+B₂O₃) Is 1.00 or more, wherein Ln is 1 or more selected from the group consisting of La, Gd, Y and Yb.

6. The optical glass according to any one of claims 1 to 5, wherein the sum of the oxide-based RO components is 5.0% or more and 60.0% or less by mass, and wherein R is 1 or more selected from the group consisting of Mg, Ca, Sr and Ba.

7. The optical glass according to any one of claims 1 to 6, wherein an oxide-based mass ratio (BaO/RO) is 0.50 or more, and wherein R is 1 or more selected from the group consisting of Mg, Ca, Sr and Ba.

8. The optical glass according to any one of claims 1 to 7, wherein the oxide-based Rn₂The sum of the mass of O components is 10.0% or less, and Rn is 1 or more selected from the group consisting of Li, Na and K.

9. The optical glass according to any one of claims 1 to 8, wherein the oxide-based mass ratio (SiO)₂+B₂O₃) Has a/F of 0.50 to 4.00, where SiO is₂Component (A) and (B)₂O₃The content of the component is a content calculated as mass% based on oxides, and the content of the component F is a content calculated as mass% based on oxides other than the component F.

10. The optical glass according to any of claims 1 to 9, characterised in that the refractive index n_dAnd Abbe number v_dSatisfy (-0.01 v)_d+2.15)≦n_d≦(-0.01ν_d+ 2.35).

11. An optical element comprising the optical glass according to any one of claims 1 to 10.

12. A preform, characterized by being composed of the optical glass of any one of claims 1 to 10, and used for polishing and/or precision press-molding.

13. An optical element produced by precision press working the preform of claim 19.