TW201542483A - Optical glass, lens preform and optical element - Google Patents

Abstract

The present invention provides an optical glass, a lens preform and an optical element using the optical glass. The optical glass is characterized by having a high refractive index, a lower Abbe number, and a higher transmissivity to visible light. The optical glass contains, by mass%, from 5.0 % or more to 40.0 % or less of P2O5 component, from 10.0 % or more to 60.0 % or less of Nb2O5 component, and the content of TiO2 is less than 20.0%. The lens preform and the optical element contain the optical glass.

Description

Optical glass, lens preforms and optical components

The present invention relates to an optical glass, a lens preform, and an optical component.

In recent years, the number of devices using optical systems has been rapidly increasing, and the number of optical components such as lenses used in various optical devices such as digital cameras and camcorders has been improved. And the requirements for miniaturization are getting stronger.

In the optical glass for producing an optical element, in particular, it is possible to reduce the weight and size of the optical element, to have a higher refractive index (n _d ) of 1.70 or higher, and to have a lower Abbe number of 25 or less (ν). The demand for glass in _d ) is very high. As the glass having a high refractive index and a low Abbe number, for example, glass represented by Patent Documents 1 to 6 is known.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 09-188540

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2010-222236

[Patent Document 3] Japanese Patent Laid-Open Publication No. 2010-260746

[Patent Document 4] Japanese Patent Laid-Open Publication No. 2011-144063

[Patent Document 5] Japanese Patent Laid-Open Publication No. 2011-144064

[Patent Document 6] Japanese Patent Laid-Open Publication No. 2011-195358

However, the glass disclosed in Patent Document 1 cannot be said that the refractive index is sufficiently high, and thus Optical glass with a higher refractive index is required. Further, in the glasses disclosed in Patent Documents 2 to 6, the transmittance of light in the visible light region (in the present specification, there is a case called "visible light transmittance"), especially the light on the short-wavelength side of the visible light region. Since the transmittance is low, only a glass colored in yellow or orange, or a glass which is not sufficiently low in Abbe number can be obtained. Therefore, an optical glass having a higher refractive index and suitable for transmitting light in a visible light region and having a lower Abbe number to improve imaging characteristics and the like is sought.

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 Abbe number and having a high transmittance to visible light, and a lens preform using the same Optical element.

Moreover, the object of the present invention is to provide an optical glass having a higher refractive index and a lower Abbe number, having a higher visible light transmittance, and a lower content of the Nb ₂ O ₅ component and lowering the material cost. , using lens preforms and optical components.

In order to solve the above problems, the inventors of the present invention have tried their best to carry out experimental research. As a result, it has been found that the glass can be improved by using a P ₂ O ₅ component and a Nb ₂ O ₅ component in combination and adjusting the content of other components including the TiO ₂ component. The refractive index, and the Abbe number becomes low, and the transmittance of the glass to visible light is improved, thereby completing the present invention.

Further, the inventors of the present invention have found that by using the TiO ₂ component and the BaO component in combination with the P ₂ O ₅ component and the Nb ₂ O ₅ component, even if the content of the Nb ₂ O ₅ component is small, the desired higher content can be obtained. The refractive index and the lower Abbe number increase the transmittance of light in the visible light region, especially on the short wavelength side.

Specifically, the present invention provides the following.

(1) An optical glass containing, by mass%, 5.0% or more and 40.0% or less of a P ₂ O ₅ component, 10.0% or more and 60.0% or less of a Nb ₂ O ₅ component, and the content of the TiO ₂ component is 20.0%. the following.

(2) The optical glass according to (1), which contains 20.0% or more and 60.0% or less of Nb ₂ O ₅ component by mass%, the content of the TiO ₂ component is 15.0% or less, and the spectral transmittance shows a wavelength of 70%. (λ ₇₀ ) is 500 nm or less.

(3) The optical glass according to (1) or (2), wherein the content of the BaO component is 25.0% or less by mass%.

(4) The optical glass according to any one of (1) to (3) which contains 10.0% or more and 55.0% or less of Nb ₂ O ₅ component by mass%, and the content of the TiO ₂ component exceeds 0% and is 20.0. % or less, and contains BaO component of 2.0% or more and 25.0% or less.

(5) The optical glass according to any one of (1) to (4), wherein the spectral transmittance shows that 70% of the wavelength (λ ₇₀ ) is 500 nm or less.

(6) The optical glass according to any one of (1) to (5), wherein the mass and (TiO ₂ + Nb ₂ O ₅ ) are 30.0% or more and 70.0% or less.

(7) The optical glass according to any one of (1) to (6), wherein a mass ratio of Nb ₂ O ₅ /(TiO ₂ +Nb ₂ O ₅ ) is 0.700 or more.

(8) The optical glass according to any one of (1) to (7) wherein the mass and (BaO+Nb ₂ O ₅ ) are 35.0% or more and 75.0% or less.

(9) The optical glass according to any one of (1) to (8), wherein the mass ratio BaO / (BaO + Nb ₂ O ₅ ) is 0.050 or more.

(10) The optical glass according to any one of (1) to (9) which contains BaO and TiO ₂ and has a mass ratio of BaO/TiO ₂ of 0.200 or more.

The optical glass according to any one of (1) to (10), wherein the content of the SiO ₂ component is 10.0% or less by mass%.

The optical glass according to any one of (1) to (11), wherein the mass and (SiO ₂ + P ₂ O ₅ ) are 5.0% or more and 40.0% or less.

(13) The optical glass according to any one of (1) to (12) wherein, in mass%, the Li ₂ O component is 0 to 10.0%, the Na ₂ O component is 0 to 15.0%, and the K ₂ O component is 0~15.0%.

The optical glass according to any one of (1) to (13), wherein the Rn ₂ O component (Rn is one or more selected from the group consisting of Li, Na, and K) is in mass%. The sum of the contents is 20.0% or less.

(15) The optical glass according to any one of (1) to (14), wherein, in mass%, the MgO component is 0 to 5.0%, the CaO component is 0 to 10.0%, and the SrO component is 0 to 10.0%.

The optical glass of any one of (1) to (15), wherein the sum of the content of the RO component (R is one or more selected from the group consisting of Mg, Ca, Sr, and Ba) is 25.0. %the following.

(17) The optical glass according to any one of (1) to (16) wherein the mass and (CaO+SrO+BaO+Rn ₂ O) are 10.0% or more and 40.0% or less (Rn is selected from Li, Na, and One or more of the groups consisting of K).

The optical glass according to any one of (1) to (17), wherein the mass ratio (CaO+SrO+BaO)/Rn ₂ O is 0.10 or more and 7.00 or less (Rn is selected from the group consisting of Li, Na, and K). One or more of the group consisting of).

(19) The optical glass according to any one of (1) to (18) wherein, in mass%, the Y ₂ O ₃ component is 0 to 10.0%, and the La ₂ O ₃ component is 0 to 10.0%, Gd ₂ O _The composition of ₃ is 0 to 10.0%, and the composition of Yb ₂ O ₃ is 0 to 10.0%.

The optical glass of any one of (1) to (19), wherein the Ln ₂ O ₃ component (Ln is one or more selected from the group consisting of Y, La, Gd, and Yb) And the ratio is 15.0% or less.

The optical glass according to any one of (1) to (20) wherein, in mass%, the B ₂ O ₃ component is 0 to 10.0%, and the GeO ₂ component is 0 to 10.0%, and the Bi ₂ O ₃ component 0~20.0%, TeO ₂ component is 0~15.0%, ZrO ₂ component is 0~10.0%, Ta ₂ O ₅ component is 0~10.0%, WO ₃ component is 0~20.0%, ZnO component is 0~10.0 %, Al ₂ O ₃ component is 0 to 10.0%, Ga ₂ O ₃ component is 0 to 10.0%, SnO component is 0 to 10.0%, and Sb ₂ O ₃ component is 0 to 3.0%.

(22) The optical glass according to any one of (1) to (21) which has a refractive index (n _d ) of 1.70 or more and an Abbe number (ν _d ) of 25 or less.

(23) An optical element comprising the optical glass according to any one of (1) to (22).

(24) A preform comprising the optical glass of any one of (1) to (22) and used for grinding processing and/or precision press forming.

(25) An optical element obtained by precisely pressurizing a preform of (24).

According to the present invention, it is possible to provide an optical glass having a high refractive index and a low Abbe number and having a high transmittance to visible light, a lens preform using the same, and an optical element.

Moreover, according to the present invention, it is also possible to provide an optical glass having a higher refractive index and a lower Abbe number, having a higher visible light transmittance, and having a lower content of the Nb ₂ O ₅ component and lowering the material cost. , using lens preforms and optical components.

The optical glass of the present invention contains 5.0% or more and 40.0% or less of P ₂ O ₅ component, 10.0% or more and 60.0% or less of Nb ₂ O ₅ component by mass%, and the content of the TiO ₂ component is 20.0% or less.

In the optical glass of the present invention, by using a P ₂ O ₅ component and a Nb ₂ O ₅ component in combination, and adjusting the content of other components including the TiO ₂ component, the refractive index of the glass can be increased, and the Abbe number becomes low. And the transmittance of light in the visible light region, especially on the short wavelength side, is improved. Therefore, an optical glass having a high refractive index and a low Abbe number and a high visible light transmittance, a lens preform using the same, and an optical element can be provided.

In addition, the first optical glass contains 5.0% or more and 40.0% or less of P ₂ O ₅ component, 20.0% or more and 60.0% or less of Nb ₂ O ₅ component by mass%, and the content of the TiO ₂ component is 15.0% or less, and The spectral transmittance shows that 70% of the wavelength (λ ₇₀ ) is 500 nm or less.

Further, the second optical glass contains 5.0% or more and 40.0% or less of P ₂ O ₅ component, 10.0% or more and 55.0% or less of Nb ₂ O ₅ component by mass%, and the content of the TiO ₂ component exceeds 0% and is 20.0. % or less, and contains BaO component of 2.0% or more and 25.0% or less.

In particular, in the second optical glass, by using the TiO ₂ component and the BaO component in combination with the P ₂ O ₅ component and the Nb ₂ O ₅ component, even if the content of the Nb ₂ O ₅ component is small, the desired higher refractive index can be obtained. The lower Abbe number. In addition, by using the BaO component in combination with the P ₂ O ₅ component and the Nb ₂ O ₅ component, and adjusting the content of each component, even if the TiO ₂ component is contained as an essential component, light in the visible light region, especially on the short wavelength side. The penetration rate has also been improved. Therefore, it is possible to provide an optical glass having a higher refractive index and a lower Abbe number, having a higher visible light transmittance, and having a lower content of the Nb ₂ O ₅ component and lowering the material cost, and using the lens pre-prepared Molded body and optical component.

Hereinafter, the embodiment of the optical glass of the present invention will be described in detail, but the present invention is not limited to the following embodiments, and may be appropriately modified within the scope of the object of the present invention. In addition, there is a case where the description is repeated, and the description is omitted as appropriate, but the gist of the invention is not limited.

[Glass composition]

The composition range of each component constituting the optical glass of the present invention will be described below. In the present specification, the content of each component is expressed by mass% of the total mass of the glass in terms of oxide composition, unless otherwise specified. Here, the "oxide-converting composition" is a composition in which an oxide, a composite salt, and a metal fluoride which are used as a raw material of the glass constituent component of the present invention are all dissolved and converted into an oxide when it is melted. In the case of this, the total mass of the produced oxide is 100% by mass, and each component contained in the glass is described.

<About essential ingredients, optional ingredients>

The P ₂ O ₅ component is a glass forming component and is an essential component for lowering the melting temperature of the glass raw material. In particular, by containing 5.0% or more of the P ₂ O ₅ component, the stability of the glass and the visible light transmittance can be improved. Therefore, the content of the P ₂ O ₅ component is preferably 5.0% as the lower limit, more preferably 10.0% as the lower limit, still more preferably 13.0% as the lower limit, still more preferably 17.0% as the lower limit, and further preferably. The lower limit is 20.0%, more preferably more than 24.0%, and further preferably 24.5%.

On the other hand, by setting the content of the P ₂ O ₅ component to 40.0% or less, the decrease in the refractive index can be suppressed. Therefore, the content of the P ₂ O ₅ component is preferably an upper limit of 40.0%, more preferably an upper limit of 35.0%, and still more preferably an upper limit of 30.0%.

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

The Nb ₂ O ₅ component is an essential component for increasing the refractive index, lowering the Abbe number, and increasing the visible light transmittance. In particular, by containing 10.0% or more of the Nb ₂ O ₅ component, a desired high refractive index can be obtained, and the Abbe number is low. Therefore, the content of the Nb ₂ O ₅ component is preferably 10.0% as a lower limit, more preferably 16.0% as a lower limit, further preferably 20.0% as a lower limit, and further preferably 22.0% as a lower limit, and further preferably. The lower limit of 25.0%, more preferably 30.0%, further preferably 35.0%, more preferably 40.0%, and still more preferably 40.0%. In particular, in the first optical glass, the content of the Nb ₂ O ₅ component can also be 45.0% as the lower limit.

On the other hand, by making the content of the Nb ₂ O ₅ component 60.0% or less, the devitrification resistance can be improved. Therefore, the content of the Nb ₂ O ₅ component is preferably an upper limit of 60.0%, more preferably an upper limit of 58.0%, further preferably an upper limit of 57.0%, more preferably an upper limit of 55.0%, and further preferably The upper limit is 53.0%. In particular, in the second optical glass, by setting the content of the Nb ₂ O ₅ component to 55.0% or less, the material cost of the glass can be lowered, and the devitrification resistance can be improved. Therefore, the content of the Nb ₂ O ₅ component in the second optical glass may preferably be an upper limit of 55.0%, more preferably an upper limit of 50.0%, still more preferably an upper limit of 48.0%, and further preferably 45.0% is the upper limit.

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

When the TiO ₂ component is contained in an amount exceeding 0%, the refractive index and the devitrification resistance of the glass are increased, the Abbe number is lowered, and the material cost of the glass is lowered. In particular, it is an essential component in the second optical glass. Therefore, the content of the TiO ₂ component may preferably be more than 0%, more preferably 0.5% as the lower limit, still more preferably 0.9% as the lower limit, still more preferably 1.2% as the lower limit, and further preferably 1.5% is the lower limit. In particular, in the second optical glass, the content of the TiO ₂ component can be 4.0% as the lower limit or 6.0% as the lower limit.

On the other hand, by setting the content of the TiO ₂ component to 20.0% or less, the visible light transmittance can be improved, and the deterioration of the devitrification resistance can be suppressed. Therefore, the content of the TiO ₂ component is preferably 20.0%, more preferably 15.0%, more preferably 11.0%, more preferably 10.0%, and even more preferably 9.0. % is an upper limit, and further preferably 8.0% is an upper limit, and further preferably 7.0% is an upper limit. In particular, in the first optical glass, the content of the TiO ₂ component can be set to an upper limit of 5.0%, and the upper limit of 4.0% can also be used.

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

When the BaO component contains more than 0%, the material cost of the glass is lowered, the refractive index is increased, the Abbe number is lowered, the devitrification resistance is improved, and the visible light transmittance is improved. Minute. In particular, it is an essential component in the second optical glass. Therefore, the content of the BaO component may preferably be more than 0%, more preferably 1.0% as the lower limit, further preferably 2.0% as the lower limit, further preferably 3.0% as the lower limit, and further preferably 3.5. % is the lower limit, and further preferably 4.0% as the lower limit, further preferably 5.0% as the lower limit, and further preferably more than 7.0%.

On the other hand, by setting the content of the BaO component to 25.0% or less, it is possible to suppress an increase in the glass transition point and the specific gravity, and to suppress a decrease in the devitrification resistance due to excessive inclusion. Therefore, the content of the BaO component is preferably an upper limit of 25.0%, more preferably an upper limit of 22.0%, further preferably an upper limit of 20.0%, more preferably an upper limit of 18.0%, and still more preferably 16.0. % is the upper limit.

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

The total content (mass sum) of the TiO ₂ component and the Nb ₂ O ₅ component is preferably 30.0% or more and 70.0% or less.

In particular, by making the total amount 30.0% or more, the refractive index can be increased and the Abbe number can be made low. Therefore, the mass and (TiO ₂ + Nb ₂ O ₅ ) are preferably 30.0% as the lower limit, more preferably 40.0% as the lower limit, still more preferably 45.0% as the lower limit, and further preferably 47.0% as the lower limit. Further preferably, the lower limit is 50.0%.

On the other hand, when the total amount is 70.0% or less, the deterioration of the devitrification resistance can be suppressed. Therefore, the mass and (TiO ₂ + Nb ₂ O ₅ ) are preferably an upper limit of 70.0%, more preferably an upper limit of 65.0%, and still more preferably an upper limit of 60.0%.

The content of Nb ₂ O ₅ with respect to the component ratio of the total content of TiO ₂ component and components of Nb ₂ O ₅ (mass ratio) is preferably 0.700 or more. Thereby, the desired high refractive index and lower Abbe number can be obtained, and the visible light transmittance can be improved to reduce the coloration. Therefore, the mass ratio Nb ₂ O ₅ /(TiO ₂ +Nb ₂ O ₅ ) is preferably a lower limit of 0.700, more preferably a lower limit of 0.800, still more preferably a lower limit of 0.830, and still more preferably 0.870. The lower limit is further preferably 0.910 as the lower limit, and more preferably 0.920 as the lower limit.

On the other hand, the upper limit of the ratio may also be 1.

The total content (mass sum) of the BaO component and the Nb ₂ O ₅ component is preferably 35.0% or more and 75.0% or less.

In particular, by setting the total amount to 35.0% or more, the refractive index can be increased and the visible light transmittance can be improved. Therefore, the mass and (BaO+Nb ₂ O ₅ ) are preferably 35.0% as the lower limit, more preferably 40.0% as the lower limit, still more preferably 45.0% as the lower limit, and still more preferably 50.0% as the lower limit.

On the other hand, when the total amount is 75.0% or less, the deterioration of the devitrification resistance can be suppressed. Therefore, the mass and (BaO+Nb ₂ O ₅ ) are preferably an upper limit of 75.0%, more preferably an upper limit of 70.0%, still more preferably an upper limit of 65.0%, and still more preferably an upper limit of 62.0%.

The ratio (mass ratio) of the content of the BaO component to the total content of the BaO component and the Nb ₂ O ₅ component is preferably 0.050 or more. Thereby, the refractive index can be increased, the visible light transmittance can be increased, and the material cost can be reduced. Therefore, the mass ratio BaO/(BaO+Nb ₂ O ₅ ) is preferably a lower limit of 0.050, more preferably a lower limit of 0.080, still more preferably a lower limit of 0.100, and still more preferably a lower limit of 0.130.

On the other hand, the ratio may preferably be an upper limit of 0.500, more preferably an upper limit of 0.400, and still more preferably an upper limit of 0.300.

The ratio (mass ratio) of the content of the BaO component to the content of the TiO ₂ component is preferably 0.200 or more. Thereby, the devitrification resistance can be improved and the visible light transmittance can be improved. Therefore, the mass ratio BaO/TiO _{2 is} preferably 0.200 as the lower limit, more preferably 0.300 as the lower limit, further preferably 0.500 as the lower limit, further preferably 0.700 as the lower limit, and further preferably 0.815 as the lower limit. Further preferably, the lower limit is 0.965.

On the other hand, the upper limit of the ratio may preferably be an upper limit of 8.000, more preferably an upper limit of 6.000, and still more preferably an upper limit of 5.000.

The SiO ₂ component is an optional component which improves the visible light transmittance and improves the resistance to devitrification by promoting the formation of a stable glass when it contains more than 0%. Therefore, the content of the SiO ₂ component may preferably be more than 0%, more preferably 0.3% as the lower limit, and still more preferably 0.4% as the lower limit.

On the other hand, when the content of the SiO ₂ component is 10.0% or less, it is possible to suppress a decrease in devitrification resistance due to excessive inclusion, that is, a decrease in devitrification resistance due to the SiO ₂ component, and thus it is possible to easily Obtain a glass with higher stability. Therefore, the content of the SiO ₂ component is preferably an upper limit of 10.0%, more preferably an upper limit of 5.0%, still more preferably an upper limit of 3.0%, still more preferably less than 1.0%.

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

The total content (mass sum) of the SiO ₂ component and the P ₂ O ₅ component is preferably 5.0% or more and 40.0% or less.

In particular, by making the total amount 5.0% or more, the stability of the glass can be improved, thereby improving the devitrification resistance. Therefore, the mass and (SiO ₂ + P ₂ O ₅ ) are preferably at a lower limit of 5.0%, more preferably at a lower limit of 10.0%, further preferably at a lower limit of 15.0%, and further preferably at a lower limit of 20.0%. Further preferably, the lower limit is 24.5%.

On the other hand, by making the total amount 40.0% or less, the decrease in the refractive index and the devitrification resistance can be suppressed. Therefore, the mass and (SiO ₂ + P ₂ O ₅ ) are preferably 40.0% or less, more preferably less than 35.0%, still more preferably less than 30.0%, still more preferably 27.0% or less.

The Li ₂ O component is an optional component which lowers the melting temperature and glass transition point of the glass raw material, and improves the devitrification resistance and visible light transmittance of the glass when the content exceeds 0%.

On the other hand, by setting the content of the Li ₂ O component to 10.0% or less, it is possible to suppress a decrease in the refractive index or an increase in the Abbe number, and to reduce devitrification caused by excessive inclusion. Therefore, the content of the Li ₂ O component is preferably 10.0% or less, more preferably less than 5.0%, still more preferably less than 3.0%, still more preferably less than 1.0%.

The Li ₂ O component can be contained in the glass, for example, using Li ₂ CO ₃ , LiNO ₃ , LiF or the like as a raw material.

When the Na ₂ O component and the K ₂ O component are contained in an amount exceeding 0%, respectively, the melting temperature of the glass raw material, the glass transition point, and the devitrification resistance and the visible light transmittance of the glass are reduced. Therefore, at least one of the Na ₂ O component or the K ₂ O component may preferably be more than 0%, more preferably more than 1.0%, still more preferably more than 3.0%, and still more preferably more than 5.0%. . Among them, in particular, the content of the Na ₂ O component alone may preferably be more than 0%, more preferably more than 1.0%, still more preferably more than 3.0%, still more preferably more than 5.0%.

On the other hand, by setting the content of the Na ₂ O component and the K ₂ O component to 15.0% or less, it is possible to suppress a decrease in the refractive index or an increase in the Abbe number, and to reduce the devitrification caused by the excessive content of the components. . Therefore, the content of each of the Na ₂ O component and the K ₂ O component is preferably 15.0%, more preferably 13.0%, still more preferably 12.0%, and still more preferably 11.0%. The upper limit is further preferably 8.0%, and more preferably 7.0%.

As the Na ₂ O component and the K ₂ O component, Na ₂ CO ₃ , NaNO ₃ , NaF, Na ₂ SiF ₆ , K ₂ CO ₃ , KNO ₃ , KF, KHF ₂ , K ₂ SiF ₆ or the like can be used as a raw material.

The total content (mass sum) of the Rn ₂ O component (one or more selected from the group consisting of Li, Na, and K) is preferably 20.0% or less.

Thereby, the decrease in the refractive index or the increase in the Abbe number can be suppressed, and the devitrification resistance can be improved. Therefore, the mass of the Rn ₂ O component is preferably an upper limit of 20.0%, more preferably an upper limit of 15.0%, still more preferably an upper limit of 13.0%, still more preferably an upper limit of 12.0%, and further preferably. The upper limit is 11.5%, more preferably 9.0%, and further preferably 7.3%.

On the other hand, it may contain a Rn ₂ O component in a total amount exceeding 0%. Thereby, the glass transition point can be lowered, the visible light transmittance can be improved, and the devitrification resistance can be improved. Therefore, the mass of the Rn ₂ O component may preferably be more than 0%, more preferably 1.0% as the lower limit, still more preferably 3.0% as the lower limit, and still more preferably 5.0% as the lower limit.

The MgO component is an optional component which improves the meltability of the glass raw material and the resistance to devitrification of the glass when it is more than 0%.

On the other hand, when the content of the MgO component is 5.0% or less, the decrease in the refractive index or the increase in the Abbe number can be suppressed, and the decrease in the devitrification resistance and the increase in the glass transition point can be suppressed. Therefore, the content of the MgO component may preferably be an upper limit of 5.0%, more preferably an upper limit of 3.0%, and still more preferably an upper limit of 1.0%.

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

The CaO component is an optional component which increases the refractive index and increases the meltability of the glass raw material and the resistance to devitrification of the glass when the content is more than 0%. Therefore, the CaO component may preferably be more than 0%, more preferably 0.1% as the lower limit, still more preferably 0.5% as the lower limit, and still more preferably 0.7% as the lower limit.

On the other hand, when the content of the CaO component is 10.0% or less, the increase in the Abbe number can be suppressed, and the decrease in the devitrification resistance and the increase in the glass transition point can be suppressed. Therefore, the content of the CaO component is preferably an upper limit of 10.0%, more preferably an upper limit of 7.0%, still more preferably an upper limit of 6.0%, and still more preferably an upper limit of 5.5%.

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

The SrO component is an optional component which improves the meltability of the glass raw material and the resistance to devitrification of the glass when it contains more than 0%.

On the other hand, by setting the content of each of the SrO components to 10.0% or less, it is possible to suppress an increase in the Abbe number and to suppress a decrease in the devitrification resistance and an increase in the glass transition point. Therefore, the content of each of the SrO components is preferably an upper limit of 10.0%, more preferably an upper limit of 7.0%, and still more preferably an upper limit of 4.0%.

As the SrO component, Sr(NO ₃ ) ₂ , SrF ₂ or the like can be used as a raw material.

The total content (mass sum) of the RO component (R is one or more selected from the group consisting of Mg, Ca, Sr, and Ba) is preferably 25.0% or less. Thereby, it is possible to suppress an increase in the glass transition point or a decrease in the devitrification resistance. Therefore, the mass of the RO component is preferably 25.0%, more preferably 23.0%, more preferably 22.0%, still more preferably 21.0%, and still more preferably 19.0. % is the upper limit, and further preferably 17.0% limit.

On the other hand, it is also possible to contain an RO component in a total amount exceeding 0%. Thereby, the meltability of the glass raw material and the devitrification resistance of the glass can be improved. Therefore, the mass of the RO component may preferably be more than 0%, more preferably 2.0% as the lower limit, still more preferably 4.0% as the lower limit, still more preferably 5.0% as the lower limit, and further preferably 6.0% is the lower limit, and further preferably 7.0% as the lower limit, further preferably 8.0% as the lower limit, and further preferably 8.5% as the lower limit. In particular, in the second optical glass, the mass of the RO component may be more than 15.0%.

The total content (mass sum) of the CaO component, the SrO component, the BaO component, and the Rn ₂ O component is preferably 10.0% or more and 40.0% or less (Rn is one or more selected from the group consisting of Li, Na, and K) .

In particular, by setting the total content to 10.0% or more, the melting temperature of the glass raw material can be lowered, the glass transition point can be lowered, and the devitrification resistance and the visible light transmittance can be improved. Therefore, the mass and (CaO+SrO+BaO+Rn ₂ O) are preferably at a lower limit of 10.0%, more preferably at a lower limit of 12.0%, and still more preferably at a lower limit of 14.5%.

On the other hand, when the total content is 40.0% or less, the deterioration of the devitrification resistance can be suppressed. Therefore, the mass and (CaO+SrO+BaO+Rn ₂ O) are preferably an upper limit of 40.0%, more preferably an upper limit of 30.0%, further preferably an upper limit of 28.0%, and further preferably 26.0%. The upper limit is further preferably 25.0%, and more preferably 21.0%.

The ratio (mass ratio) of the total content of the CaO component, the SrO component, and the BaO component to the total content of the Rn ₂ O component is preferably 0.10 or more and 7.00 or less (Rn is selected from the group consisting of Li, Na, and K). 1 or more).

In particular, by setting the ratio to 0.10 or more, the refractive index can be increased. Therefore, the mass ratio (CaO+SrO+BaO)/Rn ₂ O is preferably 0.10 as a lower limit, more preferably 0.30 as a lower limit, further preferably 0.40 as a lower limit, and further preferably 0.70 as a lower limit, and further preferably Preferably, the lower limit is 1.10, and more preferably 1.50.

On the other hand, by setting the ratio to 7.00 or less, the increase in the glass transition point can be suppressed. Therefore, the mass and (CaO + SrO + BaO + Rn ₂ O) are preferably an upper limit of 7.00, more preferably an upper limit of 5.00, still more preferably an upper limit of 4.00, and still more preferably an upper limit of 3.50.

When the Y ₂ O ₃ component, the La ₂ O ₃ component, the Gd ₂ O ₃ component, and the Yb ₂ O ₃ component are contained in an amount of more than 0%, the refractive index and the visible light transmittance are improved, and the chemical durability is increased. .

On the other hand, by setting the content of each of the Y ₂ O ₃ component, the La ₂ O ₃ component, the Gd ₂ O ₃ component, and the Yb ₂ O ₃ component to 10.0% or less, the Abbe number and the glass transition point can be suppressed from increasing. And improve resistance to devitrification. Therefore, the content of the Y ₂ O ₃ component, the La ₂ O ₃ component, the Gd ₂ O ₃ component, and the Yb ₂ O ₃ component is preferably an upper limit of 10.0%, more preferably an upper limit of 5.0%, and further preferably The upper limit is 3.0%.

As the Y ₂ O ₃ component, the La ₂ O ₃ component, and the Gd ₂ O ₃ component, Y ₂ O ₃ , YF ₃ , La ₂ O ₃ , La(NO ₃ ) ₃ ‧XH ₂ O (X is an arbitrary integer), Gd ₂ O ₃ , GdF ₃ and the like are used as raw materials.

The sum (mass sum) of the content of the Ln ₂ O ₃ component (Ln is one or more selected from the group consisting of Y, La, Gd, and Yb) is preferably 15.0% or less. Thereby, it is possible to suppress an increase in the Abbe number, a decrease in the resistance to devitrification, and an increase in the glass transition point. Therefore, the Ln ₂ O ₃ component preferably has an upper limit of 15.0%, more preferably 10.0%, more preferably 5.0%, and further preferably 3.0%.

When the B ₂ O ₃ component contains more than 0%, the meltability of the glass raw material is increased, and any component which is resistant to devitrification is promoted by promoting the formation of stable glass.

On the other hand, by setting the content of the B ₂ O ₃ component to 10.0% or less, it is possible to suppress a decrease in the refractive index or the devitrification resistance, increase the visible light transmittance, and suppress an increase in the glass transition point. Therefore, the content of the B ₂ O ₃ component is preferably an upper limit of 10.0%, more preferably an upper limit of 5.0%, further preferably an upper limit of 3.0%, further preferably less than 1.0%, and further preferably Less than 0.5%.

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

The GeO ₂ component is an optional component which increases the refractive index and devitrification resistance when it contains more than 0%.

On the other hand, by setting the content of the GeO ₂ component to 10.0% or less, the material cost of the glass can be lowered. In particular, in the second optical glass, when the GeO ₂ component is contained, the material cost of the glass is increased, thereby reducing the effect of reducing the Nb ₂ O ₅ . Therefore, the content of the GeO ₂ component is preferably 10.0% or less, more preferably 5.0% or less, further preferably less than 3.0%, more preferably less than 1.0%, and most preferably no.

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

The Bi ₂ O ₃ component is an optional component which increases the refractive index and lowers the Abbe number when it contains more than 0%.

On the other hand, by making the content of the Bi ₂ O ₃ component 20.0% or less, the devitrification resistance or the visible light transmittance can be improved. Therefore, the content of the Bi ₂ O ₃ component is preferably 20.0% or less, more preferably less than 10.0%, still more preferably less than 5.0%, and still more preferably less than 1.0%.

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

When the TeO ₂ component contains more than 0%, the meltability of the glass raw material is increased, the refractive index of the glass is increased, the Abbe number is lowered, and any component of the glass transition point is lowered.

On the other hand, by setting the content of the TeO ₂ component to 15.0% or less, the visible light transmittance can be improved and the clarification of the glass melt can be promoted. Therefore, the content of the TeO ₂ component is preferably 15.0% or less, more preferably less than 10.0%, still more preferably less than 5.0%, and still more preferably less than 3.0%.

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

The ZrO ₂ component is an optional component which increases the refractive index and the visible light transmittance and increases the resistance to devitrification when it is more than 0%.

On the other hand, when the ZrO ₂ component is made 10.0% or less, the decrease in the refractive index or the devitrification resistance due to excessive inclusion can be suppressed. Therefore, the content of the ZrO ₂ component is preferably an upper limit of 10.0%, more preferably an upper limit of 5.0%, and still more preferably an upper limit of 3.0%.

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

The Ta ₂ O ₅ component is an optional component that increases the refractive index when it contains more than 0%.

On the other hand, by setting the Ta ₂ O ₅ component to 10.0% or less, the material cost of the glass can be lowered, and the devitrification resistance can be improved. Therefore, the content of the Ta ₂ O ₅ component is preferably an upper limit of 10.0%, more preferably an upper limit of 5.0%, and still more preferably an upper limit of 3.0%.

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

The WO ₃ component is an optional component which increases the refractive index and devitrification resistance, reduces the Abbe number, and improves the meltability of the glass raw material when it contains more than 0%.

In particular, by setting the content of the WO ₃ component to 20.0% or less, devitrification due to excessive content or a decrease in visible light transmittance can be suppressed. Therefore, the content of the WO ₃ component is preferably an upper limit of 20.0%, more preferably an upper limit of 15.0%, still more preferably an upper limit of 10.0%, still more preferably an upper limit of 5.0%, and further preferably 3.0% is the upper limit.

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

When the content of the ZnO component is more than 0%, the composition of the glass material is improved in meltability and devitrification resistance, and the visible light transmittance is increased. Therefore, the ZnO component may preferably be contained in an amount of more than 0%, more preferably more than 1.0%, still more preferably more than 1.5%.

On the other hand, by increasing the content of the ZnO component to 10.0% or less, the increase in the Abbe number can be suppressed. Therefore, the content of the ZnO component is preferably an upper limit of 10.0%, more preferably an upper limit of 7.0%, and still more preferably an upper limit of 5.0%.

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

The Al ₂ O ₃ component is an optional component which increases the meltability of the glass raw material, the devitrification resistance and the chemical durability of the glass, and the viscosity at the time of melting the glass when the content is more than 0%.

On the other hand, by setting the content of the Al ₂ O ₃ component to 10.0% or less, the meltability of the glass raw material can be improved, and the devitrification resistance of the glass can be improved. Therefore, the content of the Al ₂ O ₃ component is preferably an upper limit of 10.0%, more preferably an upper limit of 5.0%, and still more preferably an upper limit of 3.0%.

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

The Ga ₂ O ₃ component is an optional component that increases the refractive index when it contains more than 0%.

On the other hand, by setting the content of the Ga ₂ O ₃ component to 10.0% or less, the devitrification resistance can be improved, and the degree of wear can be increased, and the polishing process can be easily performed. Therefore, the content of the Ga ₂ O ₃ component is preferably an upper limit of 10.0%, more preferably an upper limit of 5.0%, and still more preferably an upper limit of 3.0%.

As the Ga ₂ O ₃ component, Ga ₂ O ₃ , Ga(OH) ₃ or the like can be used as a raw material.

When the SnO ₂ component contains more than 0%, it can promote defoaming of the molten glass and increase the visible light transmittance of the glass.

On the other hand, when the content of the SnO ₂ component exceeds 10.0%, the glass is easily devitrified, and the visible light transmittance is also likely to be lowered, which in turn tends to cause alloying with a melting device (especially a noble metal such as Pt). Therefore, the content of the SnO ₂ component is preferably an upper limit of 10.0%, more preferably an upper limit of 5.0%, and still more preferably an upper limit of 3.0%. In particular, from the viewpoint of reducing the alloying of the SnO ₂ component and the melting device, the SnO ₂ component may not be contained.

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

When the Sb ₂ O ₃ component contains more than 0%, it can promote defoaming of the melted glass and increase the visible light transmittance of the glass.

On the other hand, when the content of the Sb ₂ O ₃ component exceeds 3.0%, the visible light transmittance is also likely to be lowered, and the alloying of the melting device (especially a noble metal such as Pt) is likely to occur. Therefore, the content of the Sb ₂ O ₃ component is preferably an upper limit of 3.0%, more preferably an upper limit of 1.0%, still more preferably an upper limit of 0.5%, still more preferably an upper limit of 0.2%, and further preferably The upper limit is 0.08%.

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

Further, the component for clarifying and defoaming the glass is not limited to the above-mentioned SnO component or Sb ₂ O ₃ component, and a known clarifying agent, antifoaming agent or a combination thereof in the field of glass production can be used.

<About ingredients that should not be included>

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

Other ingredients not described above may be added as needed within the scope of the characteristics of the glass of the invention of the present invention. However, each of the transition metal components such as Ce, V, Cr, Mn, Fe, Co, Ni, Cu, Ag, and Mo has the property that the glass is colored even when a small amount is contained alone or in combination. On the other hand, it is preferable to absorb the specific wavelength of the visible light region, thereby reducing the effect of improving the visible light transmittance of the present invention. Therefore, it is preferable that the optical glass that transmits the wavelength of the visible light region is substantially not contained.

Further, since a lead compound such as PbO or an arsenic compound such as As ₂ O ₃ is a component having a high environmental load, it is preferably substantially not contained, that is, it is not contained at all except inevitably.

Further, each of the components of Th, Cd, Tl, Os, Be, and Se is a harmful chemical material, and has a tendency to be controlled and used in recent years. When used, not only the manufacturing steps of the glass but also the processing steps and productization. After the treatment, it is necessary to take measures against environmental measures. Therefore, when it is important to pay attention to the influence of the environment, it is preferable that it does not substantially contain such.

The composition of the glass composition of the present invention is expressed in terms of the mass% of the total mass of the glass in terms of oxide, and therefore cannot be expressed directly in the description of the mole %, but in the glass composition satisfying the characteristics required in the present invention. The composition represented by the molar % of each component present is approximately the following value in terms of oxide conversion composition.

The P ₂ O ₅ component is 5.0 to 40.0 mol% and the Nb ₂ O ₅ component is 5.0 to 35.0 mol%, and the TiO ₂ component is 0 to 30.0 mol%, and the BaO component is 0 to 25.0 mol%, SiO _{2 .} The composition is 0~20.0 mol%, the Li ₂ O component is 0~20.0 mol%, the Na ₂ O component is 0~30.0 mol%, the K ₂ O component is 0~20.0 mol%, and the MgO component is 0~ 15.0 mole%, CaO content is 0 to 25.0 mole%, SrO content is 0 to 15.0 mole%, Y ₂ O ₃ content is 0 to 5.0 mole%, La ₂ O ₃ content is 0 to 5.0 mole% The Gd ₂ O ₃ component is 0 to 5.0 mol%, the Yb ₂ O ₃ component is 0 to 5.0 mol%, the B ₂ O ₃ component is 0 to 20.0 mol%, and the GeO ₂ component is 0 to 15.0 mol%. The Bi ₂ O ₃ component is 0 to 5.0 mol%, the TeO ₂ component is 0 to 10.0 mol%, the ZrO ₂ component is 0 to 10.0 mol%, and the Ta ₂ O ₅ component is 0 to 5.0 mol%, WO ₃ The composition is 0~10.0 mol%, the ZnO component is 0~15.0 mol%, the Al ₂ O ₃ component is 0~15.0 mol%, the Ga ₂ O ₃ component is 0~10.0 mol%, and the SnO component is 0~10.0. The molar %, Sb ₂ O ₃ component is 0 to 1.0 mol%.

In particular, the composition represented by the molar % of each component present in the composition of the first optical glass is approximately the following value in terms of oxide conversion composition.

The P ₂ O ₅ component is 8.0 to 40.0 mol% and the Nb ₂ O ₅ component is 15.0 to 35.0 mol%, and the TiO ₂ component is 0 to 25.0 mol%, and the SiO ₂ component is 0 to 20.0 mol%, Li ₂ O component is 0~20.0 mol%, Na ₂ O component is 0~30.0 mol%, K ₂ O component is 0~20.0 mol%, MgO component is 0~15.0 mol%, CaO component is 0~ 25.0 mole%, SrO content is 0 to 15.0 mole%, BaO content is 0 to 25.0 mole%, B ₂ O ₃ component is 0 to 20.0 mole%, Y ₂ O ₃ content is 0 to 5.0 mole% , La ₂ O ₃ component is 0 to 5.0 mol%, Gd ₂ O ₃ component is 0 to 5.0 mol%, Yb ₂ O ₃ component is 0 to 5.0 mol%, GeO ₂ component is 0 to 15.0 mol% , Bi ₂ O ₃ component is 0 to 5.0 mol %, TeO ₂ component is 0 to 10.0 mol %, ZrO ₂ component is 0 to 10.0 mol %, and Ta ₂ O ₅ component is 0 to 5.0 mol %, WO ₃ components are 0~10.0 mol%, ZnO component is 0~15.0 mol%, Al ₂ O ₃ component is 0~15.0 mol%, Ga ₂ O ₃ component is 0~10.0 mol%, and SnO component is 0. ~10.0 mol%, Sb ₂ O ₃ component is 0~1.0 mol%.

In addition, the composition represented by the molar % of each component present in the composition of the second optical glass is approximately the following value in terms of oxide conversion composition.

The P ₂ O ₅ component is 5.0 to 35.0 mol%, the Nb ₂ O ₅ component is 5.0 to 25.0 mol%, the TiO ₂ component is more than 0% to 30.0 mol%, and the BaO component is 2.0 to 20.0 mol%, and The SiO ₂ component is 0 to 20.0 mol%, the Li ₂ O component is 0 to 20.0 mol%, the Na ₂ O component is 0 to 30.0 mol%, and the K ₂ O component is 0 to 20.0 mol %, and the MgO component is 0~15.0 mol%, CaO component is 0~20.0 mol%, SrO component is 0~10.0 mol%, Y ₂ O ₃ component is 0~5.0 mol%, La ₂ O ₃ component is 0~5.0 mo Ear %, Gd ₂ O ₃ component is 0~5.0 mol%, Yb ₂ O ₃ component is 0~5.0 mol%, B ₂ O ₃ component is 0~15.0 mol%, GeO ₂ component is 0~10.0 mo Ear %, Bi ₂ O ₃ component is 0~5.0 mol%, TeO ₂ component is 0~10.0 mol%, ZrO ₂ component is 0~10.0 mol%, Ta ₂ O ₅ component is 0~3.0 mol% , WO ₃ component is 0~10.0 mol%, ZnO component is 0~15.0 mol%, Al ₂ O ₃ component is 0~10.0 mol%, Ga ₂ O ₃ component is 0~5.0 mol%, SnO component It is 0 to 10.0 mol%, and the Sb ₂ O ₃ component is 0 to 1.0 mol%.

[Production method]

The optical glass of the present invention is produced, for example, in the following manner. In other words, the raw material is uniformly mixed so that each component is within a specific content range, and the produced mixture is put into platinum crucible, quartz crucible or alumina crucible for coarse melting. It is packed in platinum rhodium, platinum alloy crucible or crucible, melted in the temperature range of 1100~1350 °C for 3-4 hours, stirred and homogenized, defoamed, etc., then lowered to a temperature below 1200 °C, and then completed. Stir, remove streaks, cast into the mold and allow for slow cooling.

[physical property]

The optical glass of the present invention preferably has a high transmittance of visible light transmittance, particularly light on the short-wavelength side of the visible light region, and is less colored. In particular, in the optical glass of the present invention, in the sample having a thickness of 10 mm, the spectral transmittance shows that the shortest wavelength (λ ₅ ) of 5% is preferably an upper limit of 450 nm, more preferably an upper limit of 430 nm, and further preferably The upper limit is 400 nm, and the upper limit is preferably 380 nm. Further, in the optical glass of the present invention, the shortest wavelength (λ ₇₀ ) at which the spectral transmittance shows 70% in the sample having a thickness of 10 mm is preferably an upper limit of 500 nm, more preferably an upper limit of 450 nm, and further preferably The upper limit of 430 nm is further preferably 420 nm, more preferably 413 nm, and further preferably 404 nm. Thereby, the absorption end of the glass is located at or near the ultraviolet light region, and the transparency of the glass to the light of the visible light region, especially on the short wavelength side, is further improved, thereby reducing the coloration of the glass to yellow or orange, so the optical glass can be It is preferably used for a material such as a lens that transmits visible light.

Further, it is considered that the first reason why the first optical glass of the present invention can increase the visible light transmittance is that the content of the TiO ₂ component or the like is reduced by containing a large amount of the Nb ₂ O ₅ component, and The meltability of the glass raw material is ensured by adjusting the content of other components.

Further, it is considered that one of the optical glasses of the present invention, in particular, the second optical glass can increase the visible light transmittance, because the content of the Nb ₂ O ₅ component is small to improve the meltability of the raw material, so that even The raw material can also be melted at a lower melting temperature.

The optical glass of the present invention preferably has a higher refractive index and a higher dispersion (lower Abbe number).

The refractive index (n _d ) of the optical glass of the present invention is preferably 1.70 as a lower limit, more preferably 1.80 as a lower limit, and still more preferably 1.84 as a lower limit. The upper limit of the refractive index may also preferably be 2.20, more preferably 2.10, still more preferably 2.00. By having such a high refractive index, even if the element is further thinned, a large amount of light refraction can be obtained.

Further, the Abbe number (ν _d ) of the optical glass of the present invention is preferably an upper limit of 25, more preferably an upper limit of 23, still more preferably less than 23, and still more preferably an upper limit of 22. The lower limit of the Abbe number may also preferably be 10, more preferably 15, and still more preferably 18. By having such a low Abbe number, for example, in combination with an optical element having a high Abbe number, it is possible to achieve higher imaging characteristics and the like.

Therefore, by using such an optical glass having a high refractive index and high dispersion for use in, for example, an optical element, it is possible to achieve high imaging characteristics and the like, and to expand the degree of freedom in optical design.

The optical glass of the present invention is preferably resistant to devitrification during the production of glass (in the specification, there is a case where it is simply referred to as "devitrification resistance"). Thereby, it is possible to suppress a decrease in transmittance due to crystallization of glass during production of glass, and the optical glass can be preferably used for an optical element that transmits light in a visible light region such as a lens. Further, as a standard indicating that the devitrification resistance at the time of glass production is high, for example, a liquidus temperature is low.

[Preforms and optical components]

The optical glass of the present invention is useful for various optical components and optical designs, among which It is particularly preferable to produce an optical element such as a lens, a crucible, or a mirror from the optical glass of the present invention by a method such as precision press molding. Thereby, when it is used for an optical device such as a camera or a projector that transmits light in the visible light region to the optical element, high-definition and high-precision imaging characteristics can be realized, and the optical system in the optical device can be miniaturized. Further, since the chromatic aberration is reduced by using the optical element of the optical glass, when used in an optical device such as a camera or a projector, correction using an optical element having a different partial dispersion ratio (θg, F) is not performed. High-definition and high-precision imaging characteristics can also be achieved.

Here, in the production of the optical element including the optical glass of the present invention, a strip material (plate-shaped thermoformed product) formed from optical glass or a formed by press-forming a strip-shaped material may be used. In the method of producing a preform for processing, such as grinding and polishing, a glass in a molten state may be dropped from an outlet of an outflow pipe such as platinum to prepare a preform for precision press molding such as a spherical shape. The preform for precision press molding is subjected to precision press forming.

[Examples]

The composition of the glass (No. A1 to No. A34, No. B1 to No. B18) and the comparative example (No. a) of the present invention, the refractive index (n _d ), and the Abbe number (ν _d ) The spectral transmittance shows that the wavelengths of 5% and 70% (λ ₅ , λ ₇₀ ) are shown in Tables 1 to 8. Among them, Examples (No. A1 to No. A34) are examples of the first optical glass, and Examples (No. B1 to No. B18) are examples of the second optical glass. Furthermore, the following examples are for illustrative purposes only and are not limited to the embodiments.

In the glass of the examples and the comparative examples, as the raw materials of the respective components, appropriate oxides, hydroxides, carbonates, nitrates, fluorides, hydroxides, metaphosphoric compounds, and the like are selected in usual optical glasses. The high-purity raw materials used are weighed and uniformly mixed in such a manner as to be a ratio of the compositions of the respective examples shown in the table, and then introduced into a quartz crucible or a platinum crucible according to the melting difficulty of the glass composition in the electric furnace. Melt in the temperature range of 1100~1350 °C for 3-4 hours, stir and homogenize and defoam, etc., then reduce to a temperature below 1200 °C, then finish mixing, remove the streaks, cast into the mold and slowly cool And making glass. Then, the obtained glass was annealed in the range of 550 ° C to 650 ° C for 2 to 60 hours depending on the composition.

The refractive index and Abbe number of the glass of the examples and the comparative examples are based on the glass obtained by the slow cooling rate of -25 ° C / h, based on the Japanese Optical Glass Industry Standard (JOGIS01-2003 optical glass refractive index). The measurement method is determined by performing measurement. Further, as the glass used in the measurement, it was used in a slow cooling furnace under an annealing condition in which the slow cooling rate was -25 ° C / hr.

The transmittance of the glass of the examples and the comparative examples was measured based on the Japan Optical Glass Industry Association Standard (measuring method of the chromaticity of the optical glass of JOGIS02-2003). Further, in the present invention, the presence or absence of the color of the glass is determined by measuring the transmittance of the glass. Specifically, a light transmittance of 200 to 800 nm is measured based on JIS Z8722 on a surface-parallel polished product having a thickness of 10 ± 0.1 mm, and λ ₇₀ (wavelength at a transmittance of 70%) and λ ₅ (at a transmittance of 5%) are obtained. The wavelength).

As shown in the table, λ ₇₀ (wavelength at a transmittance of 70%) of any of the optical glasses of the examples of the present invention is 500 nm or less, and more specifically 420 nm or less, and is within a desired range.

On the other hand, the λ ₇₀ of the glass of the comparative example was 515 nm.

Therefore, it is understood that the optical glass of the embodiment of the present invention has a higher transmittance to visible light than the glass of the comparative example.

The refractive index (n _d ) of any of the optical glasses of the examples of the present invention is 1.70 or more, and more specifically 1.84 or more, and is therefore within a desired range. In particular, the refractive index of the optical glass of the examples (No. B1 to No. B9) in the examples (No. B1 to No. B18) was 1.864 or more.

Further, the Abbe number (ν _d ) of any of the optical glasses of the embodiment of the present invention is 25 or less, and is therefore within a desired range.

In particular, the content of the Nb ₂ O ₅ component of the optical glass of the examples (No. B1 to No. B18) of the present invention is 55.0% or less, and more specifically 52.0% or less. In particular, the content of the Nb ₂ O ₅ component of the optical glass of the examples (No. B1 to No. B9) was 44.0% or less.

Therefore, it is estimated that the optical glass of the examples (No. B1 to No. B18) lowers the content of the Nb ₂ O ₅ component, and the material cost can be lowered even if the visible light transmittance is increased.

From the above, it is understood that the optical glass of the embodiment of the present invention has a higher refractive index (n _d ), and has a lower Abbe number (ν _d ) and a higher transmittance to visible light.

It can be seen that in particular, the optical glass of the examples (No. B1 to No. B18) lowers the content of the Nb ₂ O ₅ component and has a higher refractive index (n _d ) and a lower Abbe number (ν _d ). And the visible light transmittance is low.

Further, when the lens preform is formed using the optical glass of the embodiment of the present invention, and the lens preform is subjected to press molding, it can be stably processed into various lens shapes.

The present invention has been described in detail above for the purpose of illustration and description.

Claims (25)

An optical glass containing 5.0% or more and 40.0% or less of P ₂ O ₅ component, 10.0% or more and 60.0% or less of Nb ₂ O ₅ component by mass%, and the content of the TiO ₂ component is 20.0% or less. The optical glass of claim 1, which contains 20.0% or more and 60.0% or less of Nb ₂ O ₅ component by mass%, a content of TiO ₂ component of 15.0% or less, and a spectral transmittance of 70% of wavelength (λ _70). ) is below 500 nm. The optical glass of claim 1 or 2, wherein the content of the BaO component is 25.0% or less by mass%. The optical glass according to any one of claims 1 to 3, which contains 10.0% or more and 55.0% or less of Nb ₂ O ₅ component by mass%, and the content of the TiO ₂ component exceeds 0% and is 20.0% or less, and contains 2.0% or more and 25.0% or less of BaO component. The optical glass according to any one of claims 1 to 4, wherein the spectral transmittance shows that 70% of the wavelength (λ ₇₀ ) is 500 nm or less. The optical glass according to any one of claims 1 to 5, wherein the mass and (TiO ₂ + Nb ₂ O ₅ ) are 30.0% or more and 70.0% or less. The optical glass according to any one of claims 1 to 6, wherein the mass ratio Nb ₂ O ₅ /(TiO ₂ +Nb ₂ O ₅ ) is 0.700 or more. The optical glass according to any one of claims 1 to 7, wherein the mass and (BaO + Nb ₂ O ₅ ) are 35.0% or more and 75.0% or less. The optical glass according to any one of claims 1 to 8, wherein the mass ratio BaO / (BaO + Nb ₂ O ₅ ) is 0.050 or more. The optical glass according to any one of claims 1 to 9, which contains BaO and TiO ₂ and has a mass ratio of BaO/TiO ₂ of 0.200 or more. The optical glass according to any one of claims 1 to 10, wherein the content of the SiO ₂ component is 10.0% or less by mass%. The optical glass according to any one of claims 1 to 11, wherein the mass and (SiO ₂ + P ₂ O ₅ ) are 5.0% or more and 40.0% or less. The optical glass according to any one of claims 1 to 12, wherein the Li ₂ O component is 0 to 10.0% by mass, the Na ₂ O component is 0 to 15.0%, and the K ₂ O component is 0 to 15.0%. The optical glass according to any one of claims 1 to 13, wherein the sum of the contents of the Rn ₂ O component (Rn is one or more selected from the group consisting of Li, Na, and K) is 20.0% by mass. %the following. The optical glass according to any one of claims 1 to 14, wherein the MgO component is 0 to 5.0% by mass, the CaO component is 0 to 10.0%, and the SrO component is 0 to 10.0%. The optical glass according to any one of claims 1 to 15, wherein a sum of contents of the RO component (R is one or more selected from the group consisting of Mg, Ca, Sr, and Ba) is 25.0% or less. The optical glass according to any one of claims 1 to 16, wherein the mass and (CaO+SrO+BaO+Rn ₂ O) are 10.0% or more and 40.0% or less (Rn is selected from the group consisting of Li, Na, and K). One or more of them). The optical glass according to any one of claims 1 to 17, wherein the mass ratio (CaO+SrO+BaO)/Rn ₂ O is 0.10 or more and 7.00 or less (Rn is selected from the group consisting of Li, Na, and K). 1 or more). The optical glass according to any one of claims 1 to 18, wherein, in mass%, the Y ₂ O ₃ component is 0 to 10.0%, the La ₂ O ₃ component is 0 to 10.0%, and the Gd ₂ O ₃ component is 0 to 10.0%, Yb ₂ O ₃ component is 0~10.0%. The optical glass according to any one of claims 1 to 19, wherein a content of the Ln ₂ O ₃ component (Ln is one or more selected from the group consisting of Y, La, Gd, and Yb) is 15.0% or less. . The optical glass according to any one of claims 1 to 20, wherein, in mass%, the B ₂ O ₃ component is 0 to 10.0%, the GeO ₂ component is 0 to 10.0%, and the Bi ₂ O ₃ component is 0 to 20.0%. , TeO ₂ component is 0~15.0%, ZrO ₂ component is 0~10.0%, Ta ₂ O ₅ component is 0~10.0%, WO ₃ component is 0~20.0%, ZnO component is 0~10.0%, Al ₂ O _The composition of ₃ is 0 to 10.0%, the composition of Ga ₂ O ₃ is 0 to 10.0%, the composition of SnO is 0 to 10.0%, and the composition of Sb ₂ O ₃ is 0 to 3.0%. The optical glass according to any one of claims 1 to 21, which has a refractive index (n _d ) of 1.70 or more and an Abbe number (ν _d ) of 25 or less. An optical element comprising the optical glass of any one of claims 1 to 22. A preform comprising the optical glass of any one of claims 1 to 22 and used for grinding processing and/or precision press forming. An optical component formed by precision pressing a preform of claim 24.