KR20120125466A - Optical glass, preform and optical element - Google Patents

Abstract

Provided are an optical glass capable of more accurately correcting chromatic aberration of a lens while an Abbe's number (v _d ) is within a desired range, and a preform and an optical element using the same.
The optical glass contains less than 75.0% of the Nb ₂ O ₅ component and less than 40.0% of the P ₂ O ₅ component with respect to the total glass mass of the oxide conversion composition, and has a partial dispersion ratio (? G, F) and an Abbe number (ν _d ) of 15 to 27. The preform and the optical element are made of the optical glass.

Description

Optical glass, preforms and optical elements {OPTICAL GLASS, PREFORM AND OPTICAL ELEMENT}

TECHNICAL FIELD This invention relates to an optical glass, a preform, and an optical element.

Optical systems, such as digital cameras and video cameras, include small and large distortions called aberrations. Such aberrations are classified into monochromatic aberrations and chromatic aberrations, among which chromatic aberrations are strongly dependent on the material properties of the lens used in the optical system.

In general, chromatic aberration is corrected by combining a low dispersion convex lens and a high dispersion concave lens. However, since the aberration of the red region and the green region can be corrected only by the combination of these lenses, the aberration of the blue region remains. The aberration of the blue region that cannot be removed in this way is called a secondary spectrum. In order to correct the secondary spectrum, it is necessary to perform an optical design incorporating the trend of the g line (435.835 nm) in the blue region. At this time, partial dispersion ratios? G and F are used as indexes of the optical characteristics that are noticed in the optical design. In particular, since optical glass having an unusual partial dispersion ratio (θg, F) has a remarkable effect on aberration correction, various glasses have been developed for increasing the degree of freedom of optical design. When a lens made of these abnormally dispersed glass is used in combination with another lens, chromatic aberration can be corrected in a wide wavelength range from ultraviolet to infrared.

The partial dispersion ratios θg and F are expressed as in the following equation (1).

θg, F = (n _g -n _F ) / (n _F -n _C ) (1)

Generally in optical glass, there exists a substantially linear relationship between the partial dispersion ratio ((theta) g, F) which shows the partial dispersion of a short wavelength region, and Abbe's number ((nu) _d ). A straight line showing such a relationship connects two points indicating partial dispersion ratios and Abbe numbers of NSL7 and PBM2 on an orthogonal coordinate using partial dispersion ratios (θg, F) on the vertical axis and Abbe number (ν _d ) on the horizontal axis. It is represented by a straight line, which is called a normal line (see FIG. 1). Although normal glass used as a reference of a normal line differs for every optical glass maker, each company defines the inclination and fragment which are substantially equivalent. (NSL7 and PBM2 are optical glasses manufactured by Ohara Co., Ltd., the Abbe number (ν _d ) of PBM2 is 36.3, the partial dispersion ratio (θg, F) is 0.5828, and the Abbe number (ν _d ) of NSL7 is 60.5, partial dispersion ratio. (θg, F) is 0.5436.) From the normal line, the degree of deviation of the partial dispersion ratio and the Abbe number of the optical glass in the longitudinal axis direction is an index of the ideal dispersion of the optical glass.

Bidisperse glasses are disclosed in various literatures. For example, Patent Documents 1 to 5 disclose optical glasses having partial dispersion ratios (θg, F) of unusual values. Specifically, Patent Literatures 1 to 3 describe Abbe number (ν) as a glass of SiO ₂ -B ₂ O ₃ -ZrO ₂ -Nb ₂ O ₅ system or SiO ₂ -ZrO ₂ -Nb ₂ O ₅ -Ta ₂ O ₅ system. _d ) exists in the range of 28-55, and the optical glass in which the partial dispersion ratio ((theta) g, F) exists in the range of 0.54-0.59 is disclosed. In addition, Patent Documents 4 and 5 show glass of SiO ₂ -B ₂ O ₃ -TiO ₂ -Al ₂ O ₃ or Bi ₂ O ₃ -B ₂ O ₃ , with Abbe number (ν _d ) in the range of 32 to 55. The optical glass which exists in the inside and whose partial dispersion ratio (theta) g, F is in the range of 0.55-0.59 is disclosed.

1. Published Japanese Patent Publication No. 10-130033 2. Japanese Patent Application Publication No. 10-265238 3. International Publication No. 01/072650 Pamphlet 4. Japanese Unexamined Patent Publication No. 2003-313047 5. Japanese Patent Application Publication No. 09-020530

However, the partial dispersion ratio of the glass disclosed in patent documents 1-5 stays at a low value of 0.59 or less. Therefore, although it is necessary to have a high partial dispersion ratio (θg, F) in order to correct chromatic aberration of the lens with higher precision, the value is insufficient to correct chromatic aberration with high precision.

Moreover, since glass with high partial dispersion ratio ((theta) g, F) has a low Abbe's number ((nu) _d ), transparency to visible light becomes low (large value of (lambda ₇₀ )), it is colored yellow and orange, and it is visible It is not suitable for the use which transmits the light of an area | region. In this sense, all of the glasses disclosed in Patent Documents 1 to 5 are glasses having a high Abbe's number (v _d ).

Moreover, in the glass disclosed by patent documents 1-5, the difference (DELTA) T between glass transition point (Tg) and crystallization start temperature (Tx) was many small, and the thermal stability of these glasses was low. Therefore, when a preform material is produced from such glass, and the preform material is heat-softened and molded to produce an optical element, the produced optical element is devitrified due to crystallization of the heat-softened glass, or the optical element Or the optical properties of the

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object thereof is to obtain an optical glass, a preform and an optical element using the same, which can accurately correct chromatic aberration of a lens while the Abbe number ν _d is within a desired range. have.

In addition, an object of the present invention is to obtain an optical glass, a preform and an optical element using the same, in which the Abbe's number ν _d is within a desired range and the chromatic aberration of the lens can be more accurately corrected and the coloring is less.

In addition, an object of the present invention is to obtain an optical glass having an Abbe's number (v _d ) in a desired range and having high thermal stability while correcting chromatic aberration of a lens with higher accuracy, a preform and an optical element using the same. do.

The present inventors, the content of the result of intensive examination study in order to solve the above problems, P ₂ O ₅ component, Nb ₂ O ₅ component, and a combination of other components, and P ₂ O ₅ component, and Nb ₂ O ₅ ingredient By setting it as the predetermined range, it was found out that dispersion of glass became in the desired range, and the partial dispersion ratio ((theta) g, F) of glass became high, and came to complete this invention.

Further, by into the present inventors, P ₂ O ₅ component, Nb ₂ O ₅ component and a combination of an alkali metal, P ₂ O ₅ component, Nb ₂ O ₅ ingredients to a predetermined range of the alkaline metal components, the glass It was found that the dispersion was within a desired range, the partial dispersion ratios (? G, F) of the glass were increased, and the transparency of the glass in the visible region was increased.

In addition, the present inventors, P ₂ O ₅ component, and Nb ₂ O with a combination of ₅ components, by making the content of Nb ₂ O ₅ component and a TiO ₂ component in a predetermined range, the dispersion of the glass desired range is I, the dispersion of the glass The ratio ((theta) g, F) became high and it turned out that the transparency of glass in a visible region becomes high.

Further, while in the present inventors, P ₂ O ₅ component, and, range, dispersion of the glass desired, by into the combination of Nb ₂ O ₅ component, and, P ₂ O ₅ component, and Nb ranges the content of the ₂ O ₅ ingredient predetermined glass It was found that the partial dispersion ratios θg and F were increased and the difference ΔT between the glass transition point Tg and the crystallization start temperature Tx was increased.

Specifically, the present invention provides the following.

(1) Partial dispersion ratio (θg, 0.62 or less and 0.69 or less, containing less than 75.0% of Nb ₂ O ₅ component and less than 40.0% of P ₂ O ₅ component, based on the total mass of glass in terms of oxide composition; An optical glass having F) and having an Abbe number (ν _d ) of 15 to 27.

(2) The optical glass according to the 17% less than (1) the content of P ₂ O ₅ component to the entire mass of the glass composition in terms of oxide.

(3) The optical glass according to the 40% or less (1) or (2) the content of the TiO ₂ component of the total mass of the glass composition in terms of oxide.

(4) The optical glass according to the 30% or less (3) The content of the TiO ₂ component, the weight% based on the entire mass of the glass composition in terms of oxide.

(5) The optical glass according to the 12% or less (3) or (4) the content of the TiO ₂ component of the total mass of the glass composition in terms of oxide.

6 in terms of the oxide optical glass according to any one of (3) to (5) not less than 0.1%, the content of TiO ₂ component of the total mass of the glass composition.

7 in terms of the oxide optical glass according to any one of the content of WO ₃ ingredient 30.0% or less (1) to (6) for the entire mass of the glass composition.

(8) The optical glass according to the 13% or less (7) The content of WO ₃ components of the entire mass of the glass composition in terms of oxide.

(9) The optical glass according to the 10% or lower (7) or (8), the content of WO ₃ components of the entire mass of the glass composition in terms of oxide.

10 parts by mass of the sum total glass mass of the composition in terms of oxide _{(Nb 2 O 5 + TiO 2} + WO 3) An optical glass as defined in any one of at least 40.0% less than 64.0% (1) to (9).

(11) By mass% to the total glass mass of the oxide equivalent composition

SiO ₂ component 0-10.0% and / or

B ₂ O ₃ Component 0 ~ 10.0%

The optical glass in any one of phosphorus (1)-(10).

12. An optical glass according to any one of the total mass of the entire mass of the glass composition in terms of oxide _{(P 2 O 5 + SiO 2} + B 2 O 3) is 35% or less (1) to (11).

(13) The optical glass according to any one of (1) to (12), wherein the mass ratio (SiO ₂ + B ₂ O ₃ ) / (P ₂ O ₅ + SiO ₂ + B ₂ O ₃ ) in the oxide conversion composition is less than 0.200. .

(14) To mass% of the total glass mass of the oxide equivalent composition

Y ₂ O ₃ component 0-10.0% and / or

La ₂ O ₃ component 0-10.0% and / or

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

Yb ₂ O ₃ Component 0 ~ 10.0%

The optical glass in any one of phosphorus (1)-(13).

(15) The sum of the masses of the Ln ₂ O ₃ components (wherein Ln is at least one selected from the group consisting of Y, La, Gd, and Yb) with respect to the total mass of glass in terms of oxide composition is 15.0% or less (14) Optical glass as described in.

(16) The sum of the masses of the Ln ₂ O ₃ components (wherein Ln is one or more selected from the group consisting of Y, La, Gd, and Yb) with respect to the total glass mass of the oxide conversion composition is 0.1% or more and 15.0% or less The optical glass as described in (14) or (15).

(17) With respect to the total mass of glass in terms of oxide equivalent composition, in mass%

0-25.0% MgO component and / or

CaO component 0-25.0% and / or

0-25.0% of SrO component and / or

BaO component 0-25.0% and / or

ZnO component 0 ~ 25.0%

The optical glass in any one of phosphorus (1)-(16).

(18) The sum of the masses of the RO components (wherein R is one or more selected from the group consisting of Mg, Ca, Sr, Ba, and Zn) with respect to the total mass of the oxide in terms of oxide composition is less than or equal to 30.0%. The optical glass described.

(19) (17) wherein the sum of the masses of RO components (wherein R is one or more selected from the group consisting of Mg, Ca, Sr, Ba, and Zn) with respect to the total glass mass in terms of oxides is 15.0% or less; or The optical glass as described in (18).

(20) With respect to the total mass of glass in oxide equivalent composition, in mass%

Li ₂ O component 0-10.0% and / or

0-20.0% Na ₂ O component and / or

K ₂ O component 0-20.0% and / or

Cs ₂ O Component 0 ~ 10.0%

The optical glass in any one of phosphorus (1)-(19).

(21) The sum of the masses of the Rn ₂ O components (wherein Rn is at least one member selected from the group consisting of Li, Na, K and Cs) with respect to the total mass of the glass in terms of oxide composition is 30.0% or less in (20). The optical glass described.

(22) To (20) or (21) containing more than 0% of an Rn ₂ O component (wherein Rn is at least one selected from the group consisting of Li, Na, K and Cs) in an oxide conversion composition The optical glass described.

(23) The sum of the masses of the Rn ₂ O components (wherein Rn is at least one member selected from the group consisting of Li, Na, K and Cs) with respect to the total mass of the glass in terms of oxide composition is 0.1% or more and 30.0% or less ( The optical glass in any one of 20)-(22).

(24) A mass sum of Rn ₂ O components (wherein Rn is at least one member selected from the group consisting of Li, Na, K, and Cs) relative to the total mass of the glass in terms of oxides is greater than 1.0% (20) The optical glass as described in any one of (23)-.

(25) A mass sum of Rn ₂ O components (wherein Rn is at least one selected from the group consisting of Li, Na, K, and Cs) with respect to the total mass of the glass in terms of oxides is greater than 7.0% (20) The optical glass as described in any one of (24)-.

(26) With respect to the total glass mass of the oxide equivalent composition, in mass%

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

TeO ₂ Component 0 ~ 15.0%

The optical glass in any one of phosphorus (1)-(25).

(27) With respect to the total glass mass of the oxide equivalent composition, in mass%

Al ₂ O ₃ component 0-10.0% and / or

ZrO ₂ component 0-15.0% and / or

Ta ₂ O ₅ component 0-15.0% and / or

CeO ₂ Component 0 ~ 10.0%

The optical glass in any one of phosphorus (1)-(26).

28 in terms of an oxide optical glass according to any one of not more than 1 is 15.0%, the content of the GeO ₂ component to (27) for the entire mass of the glass composition.

29 in terms of an oxide optical glass according to any one of the content of Sb ₂ O ₃ component of 1.0% or less (1) to (28) for the entire mass of the glass composition.

30. An optical glass according to the less than 29 0.1% The content of Sb ₂ O ₃ component to the entire mass of the glass composition in terms of oxide.

The optical glass as described in (30) whose difference (DELTA) T of a glass transition point (Tg) and crystallization start temperature (Tx) is 90 degreeC or more.

(32) Partial dispersion ratios (θg, F) are Abbe's number (ν _d ) and (-4.21 × 10 ^-3 v _d +0.7207) ≤ (θg, F) ≤ (-4.21 × 10 ^-3 v _d +0.7507) The optical glass in any one of (1)-(31) which satisfy | fills the relationship of.

(33) The optical glass according to any one of (1) to (32), wherein the wavelength λ ₇₀ at which the spectral transmittance is 70% is 500 nm or less.

(34) Preform for polishing processing and / or precision press molding which consists of optical glass as described in any one of (1)-(33).

(35) An optical element formed by polishing the preform according to (34).

(36) An optical element formed by precision press molding the preform according to (34).

According to the present invention, by using the P ₂ O ₅ component, the Nb ₂ O ₅ component and other components in combination and keeping the content of the P ₂ O ₅ component and the Nb ₂ O ₅ component within a predetermined range, the Abbe number (ν _d ) is desired. Optical glass which can correct chromatic aberration of a lens with high accuracy while being in a range, and has high devitrification resistance when glass is formed in a molten state, and a wide transmission wavelength range in the visible region, Preforms and optical elements using the same can be obtained.

Further, by into accordance with the present invention, P ₂ O ₅ component, Nb ₂ O ₅ component, and a combination of the alkaline metal components, and, P ₂ O ₅ component, Nb ₂ O ₅ ingredients to a predetermined range of the alkaline metal components, and Abbe's number The optical aberration of the lens can be more precisely corrected while (ν _d ) is within the desired range, and the optical resistance is high when the glass is formed in the molten state, and the transmission wavelength range in the visible region is wide and the coloring is small. Glass, a preform and an optical element using the same can be obtained.

Furthermore, according to the present invention, while using the P ₂ O ₅ component and the Nb ₂ O ₅ component in combination with the content of the Nb ₂ O ₅ component and the TiO ₂ component within a predetermined range, while the Abbe number ν _d is within a desired range, It is possible to more accurately correct chromatic aberration of the lens, and also has high devitrification resistance when glass is formed in the molten state, wide transmission wavelength range in the visible region, and low coloring, preforms and optical elements using the same. You can get it.

Also in accordance with the present invention, P ₂ O ₅ component, and Nb ₂ O in combination of ₅ components, by making the content of P ₂ O ₅ component, and Nb ₂ O ₅ component in a predetermined range, the range is the Abbe number (ν _d) the desired In addition, the chromatic aberration of the lens can be more accurately corrected, and the optical glass having high thermal stability, wide transmission wavelength range in the visible region and low coloring, preforms and optical elements using the same can be obtained.

FIG. 1: is a figure which shows the normal line in the rectangular coordinate whose vertical axis | shaft is partial dispersion ratio (theta) g, F, and whose horizontal axis | shaft is Abbe's number ((nu) _d ).
FIG. 2 is a diagram showing a relationship between partial dispersion ratios (θg, F) and Abbe's number (v _d ) with respect to glass in the embodiment of the present invention.

The optical glass of the present invention contains less than 75.0% of the Nb ₂ O ₅ component and less than 40.0% of the P ₂ O ₅ component with respect to the total glass mass of the oxide conversion composition, and has a partial dispersion ratio of 0.62 or more and 0.69 or less. (θg, F), and has an Abbe number (ν _d ) of 15 to 27. P ₂ O ₅ component, Nb ₂ O ₅ component, and a combination of other ingredients, P ₂ O ₅ component, and Nb ₂ O by the amount of the ₅ components within a predetermined range, the dispersion of the glass spheres, and I want, dispersion of the glass The ratio [[theta] g, F] becomes high. For this reason, optical glass which can correct chromatic aberration of a lens more accurately can be obtained, while Abbe's number ((nu) _d ) is in the range of 15 or more and 27 or less.

The optical glass of the present invention is less than 75.0% of the Nb ₂ O ₅ component, less than 40.0% of the P ₂ O ₅ component, and Rn ₂ O component (in the formula, Rn contains at least one member selected from the group consisting of Li, Na, K and Cs), has a partial dispersion ratio [θg, F] of 0.62 or more and 0.69 or less, and an Abbe number (ν _d ) of 15 or more and 27 or less. It may be to have. P ₂ O ₅ component, Nb ₂ O ₅ component, and a combination of Rn ₂ O component and, P ₂ O ₅ component, Nb ₂ O ₅ component, and, range, dispersion of the glass desired by the content of Rn ₂ O component in a predetermined range It becomes inside, and the partial dispersion ratio [(theta) g, F] of glass becomes high, and transparency of glass with respect to the light of the wavelength of a visible region becomes high. For this reason, the optical glass with little coloring which can correct chromatic aberration of a lens more accurately, while having Abbe's number ((nu) _d ) in the range of 15 or more and 27 or less can be obtained.

In addition, the optical glass of the present invention, the content of the oxide in terms with respect to the glass the total mass of the composition, less than 75% of Nb ₂ O ₅ ingredient, in mass%, and P ₂ O is less than the 40.0% ₅ ingredients and, and TiO ₂ ingredients It may be 30.0% or less, having a partial dispersion ratio [θg, F] of 0.62 or more and 0.69 or less, and having an Abbe number (ν _d ) of 15 or more and 27 or less. By using the P ₂ O ₅ component and the Nb ₂ O ₅ component in combination with the content of the Nb ₂ O ₅ component and the TiO ₂ component within a predetermined range, the dispersion of the glass is within a desired range, and the partial dispersion ratio of the glass [θg, F] the As can be increased, suppressing the deterioration of the transparency of the glass for the light having a wavelength in the visible region of the TiO ₂ component. For this reason, the optical glass with little coloring which can correct chromatic aberration of a lens more accurately, while having Abbe's number ((nu) _d ) in the range of 15 or more and 27 or less can be obtained.

In addition, part of the less the optical glass of the invention, with respect to the glass the total mass of the oxide in terms of the composition, less than 75% of Nb ₂ O ₅ ingredient, in mass%, and P ₂ O ₅ component, and containing less than 40.0%, 0.62 or more 0.69 It may have a dispersion ratio [θg, F], an Abbe number (ν _d ) of 15 or more and 27 or less, and the difference ΔT between the glass transition point (Tg) and the crystallization start temperature (Tx) may be 90 ° C or more. In combination with P ₂ O ₅ component, and Nb ₂ O ₅ component, and, P ₂ O ₅ component, and Nb ₂ O by the amount of the ₅ components within a predetermined range, the dispersion of the glass desired range is i, the partial dispersion ratio [θg of glass , F] increases, and the difference ΔT between the glass transition point Tg and the crystallization start temperature Tx increases. Therefore, while the Abbe's number ν _d is in the range of 15 to 27, the chromatic aberration of the lens can be more accurately corrected, and an optical glass having high thermal stability can be obtained.

EMBODIMENT OF THE INVENTION Hereinafter, although embodiment of the optical glass of this invention is described in detail, this invention is not limited to the following embodiment, It can implement by changing suitably within the range of the objective of this invention. The description may be omitted as appropriate for the overlapping parts, but the scope of the present invention is not limited.

 [Glass component]

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

<Required ingredients and optional ingredients>

The Nb ₂ O ₅ component is a component which raises the refractive index and dispersion of glass. In particular, by containing the Nb ₂ O ₅ component as an essential component, it is possible to increase the refractive index and dispersion of the glass while increasing the partial dispersion ratio (θg, F) of the glass and the transparency to the light of the wavelength of the visible region of the glass. have. Further, by the content of Nb ₂ O ₅ component is less than 75.0%, thereby increasing the resistance to devitrification of the glass. Therefore, the content of Nb ₂ O ₅ component to the free total mass of the oxide in terms of composition, and the preferably 0.1%, more preferably 1.0%, more preferably 10.0%, most preferably 25% as the lower limit Preferably it is less than 75.0%, More preferably, it is 70.0%, Most preferably, it is 65.0%. Nb ₂ O ₅ component, for example, as a raw material using, for example, Nb ₂ O ₅ may be contained in the glass.

The P ₂ O ₅ component is a glass forming component and is a component that lowers the melting temperature of the glass. In particular, by containing the P ₂ O ₅ component as an essential component, the devitrification resistance of the glass can be increased while increasing the transparency to the light of the wavelength of the visible region of the glass. On the other hand, by making the content of P ₂ O ₅ component is less than 40.0%, can be a part of dispersion (θg, F) of the glass can not be easily reduced. Therefore, the content of the P ₂ O ₅ component with respect to the total glass mass of the oxide conversion composition is preferably 0.1%, more preferably 5.0%, still more preferably 10.0%, still more preferably 17.0%, most preferably Preferably 15.0% is a lower limit, preferably less than 40.0%, more preferably 35.0%, most preferably 33.0%. The P ₂ O ₅ component can be contained in the glass using, for example, Al (PO ₃ ) ₃ , Ca (PO ₃ ) ₂ , Ba (PO ₃ ) ₂ , BPO ₄ , H ₃ PO _4, or the like as a raw material. .

TiO ₂ component is a component improving the refractive index and dispersion of the glass, an optional component of the optical glass of the present invention. By the content of the TiO ₂ component to less than 40% may increase resistance to devitrification of the glass. Therefore, the content of TiO ₂ component of the total mass of the glass composition in terms of oxide, and a preferably 40.0%, more preferably 35.0%, most preferably from 30.0% as an upper limit. Here, the content of the TiO ₂ component relative to the total mass of the glass in the oxide conversion composition is preferably 25.0%, in that the transparency to the light of the wavelength of the visible region of the glass is particularly high while obtaining a high refractive index and dispersion. More preferably, the upper limit is 22.0%, and most preferably 20.0%.

In particular, when glass having high transparency to light having a wavelength in the visible region of the glass is obtained, the devitrification resistance of the glass can be improved by setting the content of the TiO ₂ component to 30.0% or less. Therefore, the oxide content in terms of TiO ₂ component to the entire mass of the glass composition of the case, and a preferably 30.0%, more preferably 25.0%, most preferably from 20.0% as an upper limit. Here, the content of the TiO ₂ component with respect to the total mass of the glass in terms of oxide is preferably 15.0% in that transparency to light of the wavelength of the visible region of the glass is particularly high while easily obtaining a high refractive index and dispersion. More preferably, it is 12.0%, Most preferably, it is 10.0% as an upper limit.

The optical glass of the present invention, but do not contain TiO ₂ component, it is possible to further increase the partial dispersion ratio (θg, F) of the glass by containing more than 0.1% of the TiO ₂ component. Therefore, in this case the content of the TiO ₂ component of the total mass of the glass composition in terms of oxide in is preferably about 0.1%, preferably 2.0% or more, most preferably 5.5% as the lower limit. The TiO ₂ component can be contained in glass using TiO ₂ etc. as a raw material.

WO ₃ components, to increase the partial dispersion ratio (θg, F) of the glass, a component improving the refractive index and dispersion of the glass, an optional component of the optical glass of the present invention. In particular, when the content of the WO ₃ component is 30.0% or less, a decrease in transparency to light of a wavelength in the visible region can be suppressed while reducing the devitrification at the time of reheating the glass. Accordingly, the content of the WO ₃ component relative to the total glass mass of the oxide conversion composition is preferably 30.0%, more preferably 20.0%, still more preferably 13.0%, still more preferably 12.0%, even more preferably 10.0. %, Even more preferably 7.0%, most preferably 5.0%. The WO ₃ component can be contained in glass using WO ₃ etc. as a raw material.

In the optical glass of the present invention, preferably not less than Nb ₂ O ₅ component, a content of 40.0% by weight sum of components of TiO ₂ and WO ₃ components. By setting this mass sum to 40.0% or more, it is possible to further increase the partial dispersion ratios θg and F and to easily obtain an optical glass having a desired partial dispersion ratios θg and F. On the other hand, the devitrification resistance of glass can be improved by making mass sum into 64.0% or less. Therefore, such mass sum (Nb ₂ O ₅ + TiO ₂ + Bi ₂ O ₃ ) is preferably 40.0%, more preferably 45.0%, most preferably 50.0% as a lower limit, preferably 64.0%, More preferably, it is 63.5%, Most preferably, it is 63.0% as an upper limit.

SiO ₂ component is a component which widens the transmission wavelength range of glass in a visible region, promotes stable glass formation, and improves the devitrification resistance of glass, and is an arbitrary component in the optical glass of this invention. In particular, when the content of the SiO ₂ component is 10.0% or less, it is possible to prevent the partial dispersion ratios (? G, F) and the refractive index of the glass from being easily lowered, and to increase the glass transition point (Tg). Therefore, the content of SiO ₂ component to the entire mass of the glass composition in terms of oxides is and the preferably 10.0%, preferably 7.0%, most preferably from 5.0% more than the upper limit. The SiO ₂ component can be contained in the glass using, for example, SiO ₂ , K ₂ SiF ₆ , Na ₂ SiF _6, or the like.

B ₂ O ₃ component is a component improving the devitrification of the glass to promote the stable glass formation, and any components in the optical glass of the present invention. In particular, when the content of the B ₂ O ₃ component is 10.0% or less, the partial dispersion ratio (θg, F) and the refractive index of the glass can be prevented from being easily lowered, and the rise of the glass transition point (Tg) can be suppressed. have. Therefore, the content of B ₂ O ₃ component to the entire mass of the glass composition in terms of oxide, and a preferably 10.0%, preferably 7.0%, most preferably from 5.0% more than the upper limit. B ₂ O ₃ component is, for example, as a raw material using, for example, _{H 3 BO 3, Na 2 B} 4 O 7, Na 2 B 4 O 7 and 10H ₂ O, BPO ₄ may be contained in the glass.

In the optical glass of the present invention, it is preferred that P ₂ O ₅ component, SiO ₂ component and the sum of the weight content of B ₂ O ₃ component is less than or equal to 35.0%. Since the sum of these masses is 35.0% or less, the partial dispersion ratios (θg, F) and dispersion are not easily lowered. Therefore, an optical glass having a desired partial dispersion ratio (θg, F) and Abbe's number (ν _d ) can be easily obtained. have. Therefore, this mass sum (P ₂ O ₅ + SiO ₂ + B ₂ O ₃ ) is preferably 35.0%, more preferably 32.0%, still more preferably 30.0%, still more preferably 29.0%, even more preferred. Preferably 27.0%, most preferably 26.3%. On the other hand, the lower limit of the mass sum is not particularly limited, but is preferably 0.1%, more preferably 5.0%, still more preferably 10.0%, most preferably from the viewpoint of promoting stable glass formation to increase the devitrification resistance of the glass. 15.0% is a lower limit.

In the optical glass of the present invention, the ratio of the mass sum (SiO ₂ + B ₂ O ₃ ) to the mass sum (P ₂ O ₅ + SiO ₂ + B ₂ O ₃ ) is preferably less than 0.200. Therefore, the glass-forming components among the glass transition point because (Tg) is the height component of SiO ratio of the _second component and B ₂ O ₃ component reduced, the glass of the glass obtained point (Tg) and the crystallization initiation temperature (Tx) The difference ΔT can be widened and the thermal stability of the glass can be increased. Therefore, the mass ratio (SiO ₂ + B ₂ O ₃ ) / (P ₂ O ₅ + SiO ₂ + B ₂ O ₃ ) in the oxide conversion composition is preferably less than 0.200, more preferably less than 0.100, even more preferably Is less than 0.080, most preferably less than 0.060.

Y ₂ O ₃ component, to increase the refractive index of the glass, a component to increase chemical durability of the glass, an optional component of the optical glass of the present invention. In particular, when the content of the Y ₂ O ₃ component is 10.0% or less, the dispersion of the glass may not be easily lowered and the devitrification resistance of the glass may not be easily lowered. Therefore, the content of Y ₂ O ₃ component to the entire mass of the glass composition in terms of oxide, and a preferably 10.0%, preferably 7.0%, most preferably from 5.0% more than the upper limit. Y ₂ O ₃ component is, for example, as a raw material using, for example, Y ₂ O _3, YF ₃ may be contained in the glass.

The La ₂ O ₃ component is a component which raises the refractive index of glass and raises the chemical durability of glass, and is an arbitrary component in the optical glass of this invention. In particular, when the content of the La ₂ O ₃ component is 10.0% or less, the dispersion of the glass may not be easily lowered and the devitrification resistance of the glass may not be easily lowered. Therefore, the content of La ₂ O ₃ component to the entire mass of the glass composition in terms of oxide, and a preferably 10.0%, preferably 7.0%, most preferably from 5.0% more than the upper limit. The La ₂ O ₃ component can be contained in the glass using, for example, La ₂ O ₃ , La (NO ₃ ) ₃ .XH ₂ O (X is an arbitrary integer), or the like.

Gd ₂ O ₃ component, to increase the refractive index of the glass, a component to increase chemical durability of the glass, an optional component of the optical glass of the present invention. In particular, when the content of the Gd ₂ O ₃ component is 10.0% or less, the dispersion of the glass may not be easily lowered and the devitrification resistance of the glass may not be easily lowered. Therefore, the content of Gd ₂ O ₃ component to the entire mass of the glass composition in terms of oxide, and a preferably 10.0%, preferably 7.0%, most preferably from 5.0% more than the upper limit. Gd ₂ O ₃ component is, for example, as a raw material using, for example, Gd ₂ O _3, GdF ₃ may be contained in the glass.

The Yb ₂ O ₃ component is a component which raises the refractive index of glass and raises the chemical durability of glass, and is an arbitrary component in the optical glass of this invention. In particular, when the content of the Yb ₂ O ₃ component is 10.0% or less, the dispersion of the glass may not be easily lowered and the devitrification resistance of the glass may not be easily lowered. Therefore, the content of Yb ₂ O ₃ component to the entire mass of the glass composition in terms of oxide, and a preferably 10.0%, preferably 7.0%, most preferably from 5.0% more than the upper limit. Yb ₂ O ₃ component is, for example, as a raw material using, for example, Yb ₂ O ₃ may be contained in the glass.

In the optical glass of the present invention, it is preferred that the content by weight of the sum of Ln ₂ O ₃ component (wherein, Ln is at least one element selected from the group consisting of Y, La, Gd, Yb) not more than 15.0%. By this mass sum to less than 15.0%, it is easy to obtain a desired dispersion and it is possible to suppress the increase of the Abbe's number of the Ln ₂ O ₃ component. Therefore, the content by mass of the total of Ln ₂ O ₃ component to the entire mass of the glass composition in terms of oxide, and a preferably 15%, more preferably 12.0%, most preferably from 10.0% as an upper limit. Ln ₂ O ₃ component, but do not need to contain all, by not less than at least one of 0.1% of Ln ₂ O ₃ component can be increased than the partial dispersion ratio (θg, F) of the glass. Therefore, the mass sum of content of RO component with respect to the glass total mass of oxide conversion composition in this case becomes like this. Preferably it is 0.1%, More preferably, it is 0.5%, Most preferably, let 1.0% be the lower limit.

Here, in particular, Ln ₂ O ₃ and containing the following ingredients and WO ₃ components by reducing the mass of the sum of _{(P 2 O 5 + SiO 2} + B 2 O 3), Ln 2 O 3 component and the partial dispersion ratio by WO ₃ ingredient Since (θg, F) is increased and the content of (P ₂ O ₅ + SiO ₂ + B ₂ O ₃ ) is reduced, the decrease in the partial dispersion ratios (θg, F) can be suppressed, so that the desired high partial dispersion ratio (θg, An optical glass having F) can be obtained.

MgO component is a component which lowers the liquidus temperature of glass, and improves the devitrification resistance of glass, and is an arbitrary component in the optical glass of this invention. In particular, when the content of the MgO component is 25.0% or less, the refractive index and dispersion of the glass can be prevented from easily lowering. Therefore, content of MgO component with respect to the total glass mass of oxide conversion composition becomes like this. Preferably it is 25.0%, More preferably, it is 20.0%, Most preferably, 15.0% is an upper limit. MgO component is, for example, as a raw material using a MgCO _3, MgF ₂ or the like can be contained in the glass.

CaO component is a component which lowers the liquidus temperature of glass and raises the devitrification resistance of glass, and is an arbitrary component in the optical glass of this invention. In particular, when the content of the CaO component is 25.0% or less, the refractive index and dispersion of the glass can not be easily lowered. Therefore, content of CaO component with respect to the total glass mass of oxide conversion composition becomes like this. Preferably it is 25.0%, More preferably, it is 20.0%, Most preferably, it makes an upper limit 15.0%. CaO component is, for example, as a raw material by using the CaCO _3, CaF _2, etc. may be contained in the glass.

SrO component is a component which lowers the liquidus temperature of glass and raises the devitrification resistance of glass, and is an arbitrary component in the optical glass of this invention. In particular, when the content of the SrO component is 25.0% or less, the refractive index and dispersion of the glass can not be easily lowered while the partial dispersion ratios? G and F are not easily lowered. Therefore, content of SrO component with respect to the total glass mass of oxide conversion composition becomes like this. Preferably it is 25.0%, More preferably, it is 20.0%, Most preferably, let 15.0% be an upper limit. SrO component is, for example, as a raw material by using _{Sr (NO 3) 2, SrF} 2 , etc. may be contained in the glass.

BaO component is a component which raises the refractive index and dispersion of glass, and is an arbitrary component in the optical glass of this invention. In particular, when the content of the BaO component is 25.0% or less, the specific gravity of the glass can be increased, and the partial dispersion ratios (θg, F) can be prevented from easily lowering. Therefore, content of BaO component with respect to the total glass mass of oxide conversion composition becomes like this. Preferably it is 25.0%, More preferably, it is 20.0%, Most preferably, let 15.0% be an upper limit. BaO component, for example, as a raw material using _{BaCO 3, Ba (NO 3)} 2 , etc. may be contained in the glass.

A ZnO component is a component which lowers the liquidus temperature of glass and raises the devitrification resistance of glass, and is an arbitrary component in the optical glass of this invention. In particular, when the content of the ZnO component is 25.0% or less, the partial dispersion ratios (θg, F) are not easily lowered, and the refractive index and dispersion of the glass are not easily lowered. Therefore, content of ZnO component with respect to the total glass mass of oxide conversion composition becomes like this. Preferably it is 25.0%, More preferably, it is 20.0%, Most preferably, let 15.0% be an upper limit. ZnO is a component, for example, as a raw material using ZnO, ZnF _2, etc. may be contained in the glass.

In the optical glass of this invention, it is preferable that the mass sum of content of RO component (In formula, Rn is 1 or more types chosen from the group which consists of Mg, Ca, Sr, Ba, Zn) is 30.0% or less. By setting this mass sum to 30.0% or less, the partial dispersion ratios (θg, F) and Abbe's number (ν _d ) are not easily lowered, so that the desired partial dispersion ratios (θg, F) and Abbe's number (ν _d ) can be easily obtained. Can be. Therefore, the mass sum of content of RO component becomes like this. Preferably it is 30.0%, More preferably, it is 20.0%, More preferably, it is 15.0%, More preferably, it is 10.0% as an upper limit, Most preferably, it is less than 8.0%. do. Although it is not necessary to contain an RO component, by containing RO component, the devitrification resistance of glass can be improved, and the glass transition point (Tg) can be made low by raising the transmittance | permeability of glass with respect to short wavelength visible light more. Therefore, the mass sum of content of RO component with respect to the total glass mass of oxide conversion composition becomes like this. Preferably it is 0.1%, More preferably, it is 0.2%, More preferably, let 0.5% be a minimum. In particular, the mass sum of the content of the RO component with respect to the total mass of the glass in the oxide conversion composition is more preferable from the viewpoint that the glass transition point (Tg) can be made lower and the difference ΔT from the crystallization start temperature (Tx) can be made larger. The lower limit is 1.0% and most preferably, more than 2.0%.

The Li ₂ O component is a component that lowers the glass transition point (Tg), increases the devitrification resistance of the glass, and enhances the transparency of the glass to light of the wavelength of the visible region, and is an optional component in the optical glass of the present invention. In particular, when the content of the Li ₂ O component is 10.0% or less, a decrease in the devitrification resistance of the glass due to excessive content of the Li ₂ O component can be suppressed while the partial dispersion ratio (θg, F) is not easily lowered. . Therefore, the content of Li ₂ O component to the entire mass of the glass composition in terms of oxides is and the preferably 10.0%, preferably 7.0%, most preferably from 5.0% more than the upper limit. Li ₂ O component is, for example, as a raw material using, for example, _{Li 2 CO 3, LiNO 3,} LiF may be incorporated in the glass.

The Na ₂ O component is a component that lowers the glass transition point (Tg), increases the devitrification resistance of the glass, and enhances the transparency of the glass to light of the wavelength of the visible region, and is an optional component in the optical glass of the present invention. In particular, when the content of the Na ₂ O component is 20.0% or less, a decrease in the devitrification resistance of the glass due to excessive content of the Na ₂ O component can be suppressed while the partial dispersion ratio (θg, F) is not easily lowered. Therefore, the content of Na ₂ O component to the entire mass of the glass composition in terms of oxide, and a preferably 20.0%, more preferably 17.0%, most preferably 15% as an upper limit. The Na ₂ O component can be contained in the glass using, for example, Na ₂ CO ₃ , NaNO ₃ , NaF, Na ₂ SiF _6, or the like.

K ₂ O ingredients, lower the glass transition point (Tg), increasing the resistance to devitrification of the glass, and enhance the transparency of the glass component on the wavelength of light in the visible region, and any components in the optical glass of the present invention. In particular, when the content of the K ₂ O component is 20.0% or less, a decrease in the devitrification resistance of the glass due to excessive content of the K ₂ O component can be suppressed while the partial dispersion ratio (θg, F) is not easily lowered. . Therefore, the content of K ₂ O component to the entire mass of the glass composition in terms of oxide, and a preferably 20.0%, more preferably 17.0%, most preferably 15% as an upper limit. The K ₂ O component can be contained in the glass using, for example, K ₂ CO ₃ , KNO ₃ , KF, KHF ₂ , K ₂ SiF _6, or the like.

The Cs ₂ O component is a component that lowers the glass transition point (Tg), improves the devitrification resistance of the glass, and enhances the transparency of the glass to light of the wavelength of the visible region, and is an optional component in the optical glass of the present invention. In particular, by setting the content of the Cs ₂ O component to 10.0% or less, the decrease in the devitrification resistance of the glass due to the excessive content of the Cs ₂ O component can be suppressed while the partial dispersion ratio (θg, F) is not easily lowered. . Therefore, the content of Cs ₂ O component to the entire mass of the glass composition in terms of oxides is and the preferably 10.0%, preferably 7.0%, most preferably from 5.0% more than the upper limit. Cs ₂ O component is, for example, as a raw material using, for example, Cs ₂ CO _3, CsNO ₃ may be contained in the glass.

In the optical glass of the present invention, Rn ₂ O component is preferably not more than 30.0% by weight sum of the content of (in the formula, R represents at least one element selected from the group consisting of Li, Na, K, Cs) . When the sum of the masses is 30.0% or less, the partial dispersion ratios (θg, F) and Abbe's number (ν _d ) are not easily lowered, so that the desired partial dispersion ratios (θg, F) and Abbe's number (ν _d ) can be easily obtained. have. Therefore, the mass sum of the content of the Rn ₂ O component in the oxide conversion composition is preferably 30.0%, more preferably 25.0%, and most preferably 20.0%. Although the optical glass of the present invention do not contain Rn ₂ O component, by containing more than 0.1% of at least one of Rn ₂ O component, and lower the glass transition point (Tg), in the visible region of the glass wavelength It is possible to increase the transparency to the glass and at the same time increase the devitrification resistance of the glass. Thus, the sum of the weight content of Rn ₂ O component to the entire mass of the glass composition in terms of oxide is preferably about 0.1%, preferably from 0.2 percent, more preferably from 0.5% as the lower limit.

Here, from the viewpoint that the transparency to the light of the wavelength of the visible region of the glass can be further improved, the mass sum of the content of the Rn ₂ O component with respect to the total mass of the glass in the oxide conversion composition is preferably 1.0%, more preferably. Preferably 5.0% is a lower limit and most preferably contains more than 7.0%.

In addition, by containing at least one of the Rn ₂ O components more than 1.0%, not only the transparency and devitrification resistance to visible light of the glass can be increased, but also the glass transition point (Tg) of the glass is lowered and the crystallization start temperature of the glass is reduced. Since (Tx) becomes high, the thermal stability of glass can be improved by raising these difference (DELTA) T. Thus, in particular from the viewpoint that increase the thermal stability of the glass, a weight sum of the content of Rn ₂ O component to the free total mass of the oxide in terms of the composition is preferably more than the 1.0%, more preferably 3.0%, more Preferably it is 5.0% as a minimum and most preferably contains more than 7.0%.

Bi ₂ O ₃ component is to increase the partial dispersion ratio (θg, F) of the glass, increasing the refractive index of the glass, is also a component lowering the glass transition point (Tg), is any component in the optical glass of the present invention. In particular, it is possible to widen the range of the transmission wavelength in the visible region of the glass at the same time improving the resistance to devitrification of the glass, by the content of Bi ₂ O ₃ component to less than 20.0%. Therefore, the content of Bi ₂ O ₃ component of the glass the total mass of the oxide in terms of composition, and a preferably 20.0%, preferably 15% more, more preferably 11.5%, more preferably from 10.0% to an upper limit More preferably, it is less than 10.0%, Most preferably, 9.0% is an upper limit. Bi ₂ O ₃ component is, for example, as a raw material using, for example, Bi ₂ O ₃ may be contained in the glass.

TeO ₂ is a component, a component to increase the refractive index of the glass, and any components in the optical glass of the present invention. In particular, by making the content of TeO ₂ component to less than 15%, to expand the transmission wavelength range of the visible region of the glass, it is possible to promote the fining of the glass melt. Therefore, the content of TeO ₂ components for the entire mass of the glass composition in terms of oxide is preferably less than 15%, the upper limit of preferably 12% more, and most preferably 10.0%. The TeO ₂ component can be contained in glass using TeO ₂ etc. as a raw material.

Al ₂ O ₃ component, to increase chemical durability of the glass, a component to increase the viscosity of the molten glass, and any components in the optical glass of the present invention. In particular, when the content of the Al ₂ O ₃ component is 10.0% or less, the devitrification tendency of the glass can be weakened while increasing the meltability of the glass. Therefore, the content of Al ₂ O ₃ component to the entire mass of the glass composition in terms of oxide, and a preferably 10.0%, preferably 7.0%, most preferably from 5.0% more than the upper limit. Al ₂ O ₃ component is, for example, as a raw material using, for example, Al ₂ O _3, Al (OH) _3, AlF ₃ may be contained in the glass.

The ZrO ₂ component is a component that widens the transmission wavelength range of the glass in the visible region and increases the devitrification resistance of the glass, and is an optional component in the optical glass of the present invention. In particular, when the content of the ZrO ₂ component is 15.0% or less, the refractive index of the glass can not be easily lowered. Therefore, the content of the ZrO ₂ component of the total mass of the glass composition in terms of oxide, and a preferably 15%, more preferably 12.0%, most preferably from 10.0% as an upper limit. The ZrO ₂ component is, for example, ZrO ₂ or ZrF ₄ as a raw material. It can be contained in glass using etc.

Ta ₂ O ₅ component is a component improving the refractive index of the glass, and any components in the optical glass of the present invention. In particular, when the content of the Ta ₂ O ₅ component is 15.0% or less, the devitrification tendency of the glass can be weakened. Therefore, the content of Ta ₂ O ₅ component to the entire mass of the glass composition in terms of oxides, and preferably the 15%, preferably 10% more, and most preferably from 5.0% as the upper limit. Ta ₂ O ₅ component, for example, as a raw material using, for example, Ta ₂ O ₅ may be contained in the glass.

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

GeO ₂ is a component, while increasing the resistance to devitrification of the glass, a component to increase the refractive index of the glass, and any components in the optical glass of the present invention. In particular, by the content of the GeO ₂ component to less than 15%, thereby reducing the material cost of the glass. Therefore, the content of the GeO ₂ component to the entire mass of the glass composition in terms of oxide, and a preferably 15%, more preferably 12.0%, most preferably from 10.0% as an upper limit. GeO ₂ component is, for example, as a raw material using GeO ₂ etc. may be contained in the glass.

Sb ₂ O ₃ component, to increase the transmittance of the glass for a short wavelength visible light and at the same time a component having a degassing effect elements when melting the glass, and any components in the optical glass of the present invention. In particular, by setting the content of the Sb ₂ O ₃ component to 1.0% or less, it is possible to prevent excessive foaming at the time of melting the glass, and the Sb ₂ O ₃ component is dissolved in the installation equipment (especially precious metals such as Pt). It can be prevented from alloying with easily. Therefore, the content of Sb ₂ O ₃ component of the glass the total mass of the oxide in terms of composition, preferably 1.0%, more preferably 0.5%, more preferably to 0.3% as an upper limit, and more preferably from 0.1% It is less than. Here, especially to obtain the highly transparent glass for the visible range wavelength light, is the content of Sb ₂ O ₃ component of the glass the total mass of the oxide in terms of composition, preferably more preferred, and less than 0.1% The upper limit is 0.098%, most preferably 0.096%. On the other hand, the glass can be defoamed even if it does not contain Sb ₂ O ₃ , and the desired optical glass can be obtained. However, by setting the content of the Sb ₂ O ₃ component to 0.010% or more, the defoaming effect can be exhibited without resorting to the manufacturing method. . Therefore, the content of Sb ₂ O ₃ component to the entire mass of the glass composition in terms of oxide, and a preferably 0.010%, and more preferably 0.020%, and most preferably from 0.025% as the lower limit. Sb ₂ O ₃ component is, for example, as a raw material using, for example, _{Sb 2 O 3, Sb 2 O} 5, Na 2 H 2 Sb 2 O 7 and 5H ₂ O may be contained in the glass.

Here, in particular, Rn _2, the content of Sb ₂ O ₃ component and containing O components in a predetermined range, the partial dispersion ratio (θg, F) is Rn ₂ O component and the Sb ₂ O ₃ component of the predetermined amount even in the glass increased by into Since the transmittance | permeability of glass with respect to a short wavelength visible light becomes high by this, the optical glass used suitably for the use which transmits the light of visible region with few coloring while having desired high partial dispersion ratio ((theta) g, F) can be obtained.

On the other hand, the refining of the glass component and the defoaming is not limited by the above-Sb ₂ O ₃ component and a CeO ₂ component, may be used in a known refining agent, defoamer or a combination of them in glass manufacturing.

F component is a component which has the effect of raising the meltability of glass, and the effect which enlarges an Abbe's number, and is an arbitrary component in the optical glass of this invention. Particularly, a desired optical constant can be easily realized by containing 5.0 mass% as an upper limit as a total amount of F as a part or all of one or two or more oxides of each metal element described above and substituted fluoride. When internal quality improves and heat-softens, devitrification in glass inside can be reduced. Therefore, content of F component with respect to the total glass mass of oxide conversion composition becomes like this. Preferably it is 5.0%, More preferably, 4.5%, Most preferably, let 4.0% be an upper limit. F component is introduce | transduced in glass, when the raw material form is introduce | transduced into fluoride in the introduction of the various oxide mentioned above.

In addition, in this specification, the notation "the total amount as 1 or 2 or more types of oxides of each metal element, and the substituted fluoride as F" which shows content of F component is used as a raw material of the glass structural component of this invention. When it is assumed that all oxides, complex salts, metal fluorides, and the like are decomposed at the time of melting and changed into oxides, the mass of the F atoms actually contained relative to the total mass of the produced oxide is expressed as a mass percentage.

<About ingredients which should not be contained>

Next, the component which should not be contained in the optical glass of this invention, and the component which is not preferable when it contains is demonstrated.

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

In addition, each transition metal component such as V, Cr, Mn, Fe, Co, Ni, Cu, Ag, and Mo, except for Ti, Zr, Nb, W, La, Gd, Y, Yb, and Lu, is a single or Even when a small amount is contained in the composite, the glass is colored and has a property of causing absorption at a specific wavelength in the visible region. Therefore, it is preferable that the glass is substantially free of optical glass using the wavelength in the visible region.

Moreover, lead compounds such as PbO and the components of Th, Cd, Tl, Os, Be, and Se tend to refrain from being used as harmful chemicals in recent years. It needs environmental measures to get to. Therefore, in the case of emphasizing the environmental impact, it is preferable not to contain these substantially except inevitable mixing. As a result, the optical glass is substantially free of substances that pollute the environment. As a result, such optical glass can be manufactured, processed, and disposed without taking special environmental measures.

The glass composition of the present invention is not expressed directly in terms of mol% because its composition is expressed in mass% of the total mass of glass in terms of oxide, but the glass composition satisfying the properties required in the present invention. The composition by mol% display of each component which exists in the inside takes the following values substantially in oxide conversion composition.

0.1-30.0% of P ₂ O ₅ component and

0.1-45.0% of Nb ₂ O ₅ component,

And

0-60.0% TiO ₂ component and / or

WO ₃ component 0-15.0% and / or

0-25.0% of SiO ₂ component and / or

0-25.0% of B ₂ O ₃ components and / or

0-7.0% Y ₂ O ₃ component and / or

0-7.0% La ₂ O ₃ component and / or

0-7.0% of Gd ₂ O ₃ component and / or

Yb ₂ O ₃ component 0-7.0% and / or

0-60.0% MgO component and / or

CaO component 0-50.0% and / or

0-40.0% of SrO component and / or

BaO component 0-25.0% and / or

ZnO component 0-40.0% and / or

0 to 40.0% of Li ₂ O component and / or

0-45.0% Na ₂ O component and / or

K ₂ O component 0-30.0% and / or

0 to 12.0% Cs ₂ O component and / or

0-7.0% of Bi ₂ O ₃ component and / or

TeO ₂ component 0-15.0% and / or

0-25.0% Al ₂ O ₃ component and / or

ZrO ₂ component 0-17.0% and / or

Ta ₂ O ₅ component 0-5.0% and / or

0-20.0% of GeO ₂ component and / or

Sb ₂ O ₃ Component 0 ~ 0.5%

[Manufacturing method]

The optical glass of this invention is produced as follows, for example. That is, the above-mentioned raw materials are uniformly mixed so that each component is within a range of a predetermined content, and the prepared mixture is poured into a platinum crucible, a quartz crucible or an alumina crucible, and coarsely melted, followed by a platinum crucible, a platinum alloy crucible or Put in an iridium crucible and melt for 3 to 4 hours in the temperature range of 1100 ~ 1350 ℃, remove the foam by stirring and homogenizing, and then lowered to a temperature of 1200 ℃ or less, and then subjected to the final stirring to remove the striae, and injected into the mold It is produced by cooling.

 [Properties]

It is necessary for the optical glass of this invention to have desired dispersion (abbe number). In particular, the Abbe's number (ν _d ) of the optical glass of the present invention is preferably 15, more preferably 16, most preferably 17 being a lower limit, preferably 27, more preferably 25, most preferably The upper limit is 23. For this reason, the freedom degree of optical design when using the optical glass of this invention for an optical element can be expanded significantly.

In addition, the optical glass of the present invention has a high partial dispersion ratio (θg, F). More specifically, partial dispersion ratio ((theta) g, F) of the optical glass of this invention becomes like this. Preferably it is 0.62, More preferably, it is 0.625, Most preferably, let 0.63 be a minimum. For this reason, since the optical glass which has a large abnormal partial dispersion ((DELTA) (theta) g, F) can be obtained, it can exhibit a remarkable effect in the correction of the chromatic aberration of an optical element, and can extend the freedom of optical design. In addition, although the upper limit of the partial dispersion ratio ((theta) g, F) of the optical glass of this invention is not specifically limited, It is about 0.69 or less, More specifically, it is 0.68 or less, More specifically, it is 0.67 or less.

Moreover, the optical glass of this invention has desired partial dispersion ratio ((theta) g, F) by the relationship with Abbe's number ((nu) _d ), and can correct chromatic aberration of a lens more accurately. More specifically, the partial dispersion ratio (θg, F) of the optical glass of the present invention is (-4.21 × 10 ⁻³ ν _d +0.7207) ≦ (θg, F) ≦ with the Abbe number ν _d . (-4.21 × 10 ⁻³ ν _d +0.7507) is satisfied. For this reason, since optical glass which has a desired abnormal dispersion can be obtained, chromatic aberration of the lens in an optical apparatus can be corrected with high precision. Here, the partial dispersion ratio (θg, F) of the optical glass is preferably (-4.21 × 10 ⁻³ ν _d +0.7207), more preferably (-4.21 × 10) between the Abbe numbers ν _d . ^-3 v _d +0.7227), and most preferably (-4.21 x 10 ^-3 v _d +0.7247) as a lower limit. On the other hand, the partial dispersion ratio (θg, F) of the optical glass is preferably (-4.21 × 10 ⁻³ ν _d +0.7507) between Abbe's number (ν _d ), and more preferably (-4.21 × 10 ^{− 3} ν _d +0.7487), most preferably (-4.21 × 10 ⁻³ ν _d +0.7467) as the upper limit.

In addition, the optical glass of the present invention has a high thermal stability. In particular, the difference ΔT between the glass transition point (Tg) and the crystallization start temperature (Tx) is preferably 90 ° C, more preferably 95 ° C, and most preferably 100 ° C. For this reason, even if the optical glass of this invention produces preform materials, such as a preform for precision press molding, and heat-softens this, and manufactures an optical element, since the formation of crystal nucleus and crystal growth in glass are suppressed, The influence on the optical characteristics of the optical element, including devitrification due to crystallization, can be reduced. In addition, the upper limit of (DELTA) T of the optical glass of this invention is not specifically limited, The upper limit is suitably set according to a technical level. Here, (DELTA) T of the glass obtained by this invention is about 300 degrees C or less, specifically 250 degrees C or less, and more specifically 200 degrees C or less.

Moreover, it is preferable that the optical glass of this invention has little coloring. In particular, the optical glass of the present invention has a wavelength of λ ₇₀ of 500% or less, more preferably 480 nm or less, most preferably 450 nm or less, in terms of the transmittance of the glass, indicating a 70% spectral transmittance with a sample having a thickness of 10 mm. to be. Further, the wavelength λ ₅ representing the spectral transmittance of 5% is 450 nm or less, more preferably 420 nm or less, and most preferably 400 nm or less. For this reason, since the absorption end of glass is located in the ultraviolet region or its vicinity, since transparency of glass in a visible region becomes high, this optical glass can be used suitably as a material of optical elements, such as a lens.

Moreover, it is preferable that the optical glass of this invention has a glass transition point (Tg) of 750 degreeC or less. For this reason, when shape | molding glass, since glass softens at lower temperature, it can shape | mold glass at lower temperature. Moreover, especially when precision press molding glass, oxidation of a metal mold | die can be reduced and long life of a metal mold | die can also be attained. Therefore, the glass transition point (Tg) of the optical glass of the present invention is preferably 750 ° C, more preferably 740 ° C, and most preferably 730 ° C. In addition, the minimum of the glass transition point Tg of the optical glass of this invention is not specifically limited, The upper limit is suitably set according to a technical level. Here, the glass transition point (Tg) of the glass obtained by this invention is about 100 degreeC or more, specifically 150 degreeC or more, More specifically, it is 200 degreeC or more in many cases.

Moreover, it is preferable that the optical glass of this invention has a desired refractive index. More specifically, the refractive index n _d of the optical glass of the present invention is preferably 1.75, more preferably 1.77, and most preferably 1.80. As a result, the degree of freedom in optical design is increased, and a large amount of light can be obtained even if the device is thinner. On the other hand, the upper limit of the refractive index n _d of the optical glass of the present invention is not particularly limited, but is usually 2.20 or less, more specifically 2.15 or less, and more specifically 2.10 or less.

 [Preform and Optical Device]

The optical glass of the present invention is useful for various optical elements and optical designs. Especially, it is preferable to manufacture optical elements, such as a lens, a prism, and a mirror, using means, such as precision press molding, with the optical glass of this invention. Therefore, when used in an optical device that transmits visible light to an optical device such as a camera or a projector, it is possible to miniaturize the optical system in these optical devices while realizing very fine and high precision imaging characteristics. In addition, since chromatic aberration is reduced by the optical element using this optical glass, when used in optical equipment such as a camera or a projector, even if correction by an optical element having different partial dispersion ratios (θg, F) is not performed, Very fine and high precision imaging characteristics can be realized.

Here, in order to manufacture the optical element which consists of the optical glass of this invention, grinding | polishing etc. are carried out with respect to the strip material (plate-shaped hot-molded article) formed with optical glass, and the preform for abrasive processing formed by press molding a strip material. Cold processing can be used, and a method for producing can be used. The molten glass is dropped from an outlet of an outflow pipe such as platinum to produce a preform for precision press molding such as spherical shape, and the preform for precision press molding. Precision press molding can also be performed. In particular, by forming the preform for polishing by using the optical glass of the present invention, the devitrification due to reheating when press molding the strip material is reduced, and thus an optical element suitable for the application for transmitting visible light by cold working the preform for polishing. Can be obtained. In addition, by forming the preform for precision press molding with the optical glass of the present invention, devitrification due to reheating during the precision press molding of the preform is reduced, so that an optical element suitable for the application for transmitting visible light can be obtained.

[Example]

The composition of the glass of Examples (No. 1 to No. 36) and Comparative Example (No. A) of the present invention, the refractive index (n _d ), Abbe's number (ν _d ), partial dispersion ratio (θg, F), the glass transition point (Tg), the crystallization start temperature (Tx), the difference between the glass transition point and the crystallization start temperature (ΔT), and the wavelength (λ ₇₀ , λ ₅ ) showing spectral transmittances of 70% and 5% The results are shown in Tables 1 to 8. In addition, the relationship of the Abbe's number ((nu) _d ) and partial dispersion ratio ((theta) g, F) in the glass of Example (No.1-No.36) is shown in FIG. In addition, the following Examples are for the purpose of illustration only, and are not limited only to these Examples.

The optical glass of Examples (No. 1 to No. 36) of the present invention and the glass of Comparative Example (No. A) are all equivalents of oxides, hydroxides, carbonates, nitrates, fluorides, hydroxides, and the like as raw materials of the respective components. High purity raw materials used for ordinary optical glass such as metaphosphate compounds are selected, weighed so as to have the composition ratios of the examples shown in Tables 1 to 8, mixed uniformly, and then charged into a quartz crucible or a platinum crucible, Depending on the melting difficulty of the composition melted for 3 to 4 hours in the temperature range of 1100 ~ 1350 ℃ in the electric furnace, stirred homogenizing to remove the foam, then lowered to a temperature of 1200 ℃ or less, and then subjected to the final stirring to remove the striae, mold Injected and cooled to prepare a glass.

Here, the refractive index n _d , Abbe's number ν _d , and partial dispersion ratio (θg, F) of the optical glass of Examples (No. 1 to No. 36) and the glass of Comparative Example (No.A) are And about the glass obtained by making the slow cooling down temperature velocity into -25 degreeC / h, it calculated | required by measuring based on Japanese Optical Glass Industry Standard JOGIS01-2003. Then, with respect to the values of the calculated Abbe number ν _d and the partial dispersion ratios θg and F, the intercept when the inclination a in the relation (θg, F) = − a × ν _d + b is 0.00421 ( b) was obtained.

In addition, (DELTA) T of the optical glass of an Example (No.1-No.36) and the glass of a comparative example (No.A) was the glass measured using the parallax measurement apparatus (STA 409 CD by Nech Geretebau Co., Ltd.). It calculated | required from the difference of transition point (Tg) and crystallization start temperature (Tx). The sample particle size at this time was 425-600 micrometers, and the temperature increase rate was 10 degreeC / min.

In addition, the transmittance | permeability of the optical glass of the Example (No. 1-No. 36) and the glass of the comparative example (No.A) was measured according to Japanese Optical Glass Industry Standard JOGIS02. In addition, in this invention, the presence or absence of glass coloring was calculated | required by measuring the transmittance | permeability of glass. Specifically, a spectral transmittance of 200 to 800 nm was measured for a face parallel abrasive product having a thickness of 10 ± 0.1 mm according to JISZ8722, and λ ₇₀ (wavelength when the transmittance was 70%) and λ ₅ (wavelength when the transmittance was 5%). ) Was obtained.

As shown in Tables 1 to 8, all of the optical glasses of the examples of the present invention had an Abbe number (v _d ) of 15 or more, more specifically 18 or more, and at the same time, the Abbe number (v _d ) of 27 or less. It was 23 or less in detail, and was in the desired range.

In the optical glass according to the embodiment of the present invention, the partial dispersion ratios θg and F are all 0.62 or more, more specifically 0.63 or more, and the partial dispersion ratios θg and F are 0.69 or less, more specifically. It was 0.66 or less and was in the desired range. As shown in FIG. 2, the values of the partial dispersion ratios θg and F are all equal to or greater than (-4.21 × 10 ⁻³ ν _d +0.7207), more specifically, in relation to the Abbe number ν _d . -4.21 × 10 ⁻³ ν _d +0.725) and at the same time, the partial dispersion ratios (θg, F) are all (-4.21 × 10 ^-3 ν _d +0.7507), more specifically (-4.21 × 10 ^-3 v _d +0.735) or less and within a desired range.

Moreover, as for the optical glass of the Example of this invention, it became clear that the difference (DELTA) T between a glass transition point (Tg) and crystallization start temperature (Tx) is 90 degreeC or more, more specifically 100 degreeC or more, and high thermal stability.

Moreover, as for the optical glass of the Example of this invention, (lambda) ₇₀ (wavelength when 70% of the transmittance | permeability) was 500 nm or less, More specifically, it was 440 nm or less. In particular, as for the optical glass except the Example (No. 1, No. 3) of this invention, it became clear that (lambda) ₇₀ is 435 nm or less in all, and there is less coloring.

In addition, the glass transition point (Tg) of the optical glass of the Example of this invention was 750 degrees C or less, and specifically 725 degrees C or less.

In addition, all of the optical glasses of the Example of this invention had refractive index (nd) 1.75 or more, More specifically, 1.81 or more, At the same time, this refractive index (nd) was 2.20 or less, More specifically, it was 1.95 or less.

Therefore, it became clear that the optical glass of the Example of this invention has high thermal stability, little coloring, and small chromatic aberration, while Abbe number ((nu) _d ) exists in the desired range.

Moreover, when the preform for precision press molding was formed using the optical glass of the Example of this invention, and the precision press molding preform for precision press molding, it was able to process stably in various lens shapes.

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

Claims (27)

It contains less than 75.0% of the Nb ₂ O ₅ component and less than 40.0% of the P ₂ O ₅ component with respect to the total glass mass of the oxide conversion composition, and has a partial dispersion ratio (θg, F) of 0.62 or more and 0.69 or less. , Optical glass having Abbe number (ν _d ) of 15 or more and 27 or less. The method of claim 1,
Optical glass not less than 17% content of P ₂ O ₅ component to the entire mass of the glass composition in terms of oxide. 3. The method according to claim 1 or 2,
If the content of TiO ₂ component of the total mass of the glass composition in terms of oxide and 40.0% less than optical glass. The method of claim 3, wherein
Optical glass not less than 0.1%, the content of TiO ₂ component of the total mass of the glass composition in terms of oxide. The method according to any one of claims 1 to 4,
When the content of WO ₃ components of the entire mass of the glass composition in terms of oxides 30.0% or optical glass. The method according to any one of claims 1 to 5,
Mass sum _{(Nb 2 O 5 + TiO 2} + WO 3) the optical glass is not more than 64.0% to 40.0% of the total mass of the glass composition in terms of oxide. 7. The method according to any one of claims 1 to 6,
By mass% with respect to the total glass mass of oxide conversion composition
SiO ₂ component 0-10.0% and / or
B ₂ O ₃ Component 0 ~ 10.0%
Optical glass. 8. The method according to any one of claims 1 to 7,
Mass sum _{(P 2 O 5 + SiO 2} + B 2 O 3) the optical glass is not more than 35.0% of the total mass of the glass composition in terms of oxide. 9. The method according to any one of claims 1 to 8,
The mass ratio of the composition in terms of oxides _{(SiO 2 + B 2 O 3} ) / (P 2 O 5 + SiO 2 + B 2 O 3) is less than 0.200 optical glass. 10. The method according to any one of claims 1 to 9,
By mass% with respect to the total glass mass of oxide conversion composition
Y ₂ O ₃ component 0-10.0% and / or
La ₂ O ₃ component 0-10.0% and / or
0-10.0% of Gd ₂ O ₃ component and / or
Yb ₂ O ₃ Component 0 ~ 10.0%
Optical glass. The method of claim 10,
An optical glass having a sum of masses of Ln ₂ O ₃ components (wherein Ln is at least one selected from the group consisting of Y, La, Gd, and Yb) with respect to the total mass of the glass in terms of oxide, of 15.0% or less. The method according to claim 10 or 11,
An optical glass having a sum of masses of Ln ₂ O ₃ components (wherein Ln is one or more selected from the group consisting of Y, La, Gd, and Yb) with respect to the total glass mass in terms of oxide, in a range of 0.1% to 15.0%. The method according to any one of claims 1 to 12,
By mass% with respect to the total glass mass of oxide conversion composition
0-25.0% MgO component and / or
CaO component 0-25.0% and / or
0-25.0% of SrO component and / or
BaO component 0-25.0% and / or
ZnO component 0 ~ 25.0%
Optical glass. The method of claim 13,
An optical glass in which the sum of the masses of the RO component (wherein R is one or more selected from the group consisting of Mg, Ca, Sr, Ba, and Zn) with respect to the total glass mass in terms of oxide is 30.0% or less. The method according to any one of claims 1 to 14,
By mass% with respect to the total glass mass of oxide conversion composition
Li ₂ O component 0-10.0% and / or
0-20.0% Na ₂ O component and / or
K ₂ O component 0-20.0% and / or
Cs ₂ O Component 0 ~ 10.0%
Optical glass. 16. The method of claim 15,
An optical glass in which the sum of the masses of Rn ₂ O components (wherein Rn is at least one selected from the group consisting of Li, Na, K, and Cs) is 30.0% or less with respect to the total mass of the glass in terms of oxide. 17. The method according to claim 15 or 16,
An optical glass containing more than 0% of an Rn ₂ O component (wherein, Rn is one or more selected from the group consisting of Li, Na, K, and Cs) in an oxide conversion composition. The method according to any one of claims 1 to 17,
By mass% with respect to the total glass mass of oxide conversion composition
0-20.0% of Bi ₂ O ₃ component and / or
TeO ₂ Component 0 ~ 15.0%
Optical glass. The method according to any one of claims 1 to 18,
By mass% with respect to the total glass mass of oxide conversion composition
Al ₂ O ₃ component 0-10.0% and / or
ZrO ₂ component 0-15.0% and / or
Ta ₂ O ₅ component 0-15.0% and / or
CeO ₂ Component 0 ~ 10.0%
Optical glass. The method according to any one of claims 1 to 19,
Is 15.0% or less, optical glass content of the GeO ₂ component to the entire mass of the glass composition in terms of oxide. 21. The method according to any one of claims 1 to 20,
When the content of Sb ₂ O ₃ component to the entire mass of the glass composition in terms of oxides of 1.0% or less optical glass. 22. The method of claim 21,
Optical glass whose difference (DELTA) T between a glass transition point (Tg) and crystallization start temperature (Tx) is 90 degreeC or more. The method according to any one of claims 1 to 22,
The partial dispersion ratios (θg, F) are (-4.21 × 10 ⁻³ × ν _d +0.7207) ≦ (θg, F) ≦ (-4.21 × 10 ⁻³ × ν _d + between Abbe's number (ν _d ). Optical glass satisfying the relationship of 0.7507). The method according to any one of claims 1 to 23,
The optical glass whose wavelength (lambda ₇₀ ) which shows a spectral transmittance 70% is 500 nm or less. A preform for polishing and / or precision press molding comprising the optical glass according to any one of claims 1 to 24. The optical element formed by grinding the preform of Claim 25. The optical element formed by precision press molding the preform of Claim 25.

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