TWI601704B - Optical glass, optical components and pre-form - Google Patents

Description

Optical glass, optical components and preforms

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

Lens systems of optical machines are typically combined to design a plurality of glass lenses having different optical properties. In recent years, the degree of freedom in designing lens systems for a variety of optical devices has been further expanded, and optical glasses having optical characteristics that have not been used before are gradually being used as optical elements such as spherical and aspherical lenses. In particular, in optical design, in order to reduce the chromatic aberration of the entire optical system, it is developed to have a different refractive index or dispersion tendency.

In the optical glass for producing an optical element, in particular, it is possible to reduce the weight and size of the optical element, and to have a high refractive index (nd) and a high Abbe number (νd). As such a high refractive index low-dispersion glass, for example, an optical glass having a refractive index of 1.50 or more and 1.60 or less and an Abbe number of 60 or more and 80 or less is known as a glass represented by Patent Documents 1 to 4.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. Hei 01-219037

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2007-099525

[Patent Document 3] Japanese Patent Laid-Open Publication No. 2009-256149

[Patent Document 4] Japanese Patent Laid-Open Publication No. 2010-235429

In recent years, optical components incorporated in optical devices such as projectors, photocopiers, laser printers, and broadcast machines are gradually being used in harsher temperature environments. For example, in order to meet the requirements of miniaturization and high resolution, it is necessary to use a high-intensity light source or a highly-accurate optical system. Especially in the case of using a high-intensity light source, the temperature of the optical element constituting the optical system tends to vary greatly depending on the heat generated by the light source, and the temperature thereof is more than 100 ° C. In this case, when a highly-precision optical system is used, the influence on the imaging characteristics of the optical system caused by the temperature fluctuation is so large that it cannot be ignored. Therefore, it is required to constitute a change in optical characteristics that does not occur due to temperature fluctuation. Optical system.

Further, as in the optical system of an optical device having a high resolution, an optical system that requires extremely high refractive index has a situation in which the influence of the use temperature on the imaging characteristics and the like cannot be ignored.

However, as in the prior optical glass described in Patent Documents 1 to 4, the variation in optical characteristics due to temperature fluctuation is large. That is, it is expected to develop an optical glass having a high refractive index and a high Abbe number without causing a change in optical characteristics due to temperature fluctuation.

The object of the present invention is to solve the above problems.

That is, an object of the present invention is to provide an optical glass, a preform using the same, and an optical element which can obtain optical characteristics such as desired imaging characteristics over a wider temperature range.

The inventors of the present invention have diligently studied to solve the above problems, thereby completing this invention. Specifically, the present invention provides the following.

(1) An optical glass comprising P ⁵⁺ , Al ³⁺ and Mg ²⁺ as a cationic component, O ² and F ⁻ as an anion component, and a temperature coefficient of relative refractive index (589.29 nm) (20-40) °C) is -6.0 × 10 ^-6 (°C ^-1 ) or more.

(2) The optical glass according to (1), which is represented by cation % (% by mole), and contains P ⁵⁺ 20 to 55%, Al ^{3 +} 1 to 20%, and Mg ²⁺ 0.1 to 30%.

(3) The optical glass of (1) or (2), wherein the content of Ca ²⁺ is 0 to 30%, and the content of Sr ²⁺ is 0 to 30%, expressed as % of cation (% by mole). The content of Ba ²⁺ is 0 to 30%.

(4) The optical glass according to any one of (1) to (3) wherein the total content of the alkaline earth metals (R ²⁺ : cation %) is 30 to 70%.

(5) The optical glass according to any one of (1) to (4), wherein the Mg ²⁺ content and the total amount of Ca ²⁺ (cation %) are 7.5 to 50%.

(6) The optical glass according to any one of (1) to (5), wherein the ratio of the Mg ²⁺ content and the total content of Ca ^{2+ to} the total content of the alkaline earth metal (R ²⁺ : cation %) ( (Mg ²⁺ + Ca ²⁺ ) / R ²⁺ ) is 0.25 or more.

(7) (1) to (6) The optical glass according to any one of, wherein the anionic% (mole%) represents, F ^- content ratio of 20 ~ 70%, O ^2- of 30 to contain the 80%.

(8) The optical glass according to any one of (1) to (7), wherein a ratio of Mg ²⁺ content (cation %) to P ⁵⁺ content (cation %) (Mg ²⁺ /P ⁵⁺ ) is 0.25 or more.

(9) The optical glass according to any one of (1) to (8), wherein the content of La ³⁺ is 0 to 10%, and the content of Gd ³⁺ is 0, expressed as % of cation (% by mole). ~10%, the content of Y ³⁺ is 0 to 10%, the content of Yb ³⁺ is 0 to 10%, and the content of Lu ³⁺ is 0 to 10%.

(10) The optical glass of any one of (1) to (9), wherein a total content of La ³⁺ , Gd ³⁺ , Y ³ +, Yb ³ + and Lu ³⁺ (Ln ³⁺ : cationic %) ) is 0~20%.

(11) The optical glass according to any one of (1) to (10), wherein the content of Li ⁺ is 0 to 20%, and the content of Na ⁺ is 0 to 10, expressed as % of cation (% by mole). %, K ⁺ content is 0~10%.

The optical glass of any one of (1) to (11), wherein the total content (Rn ⁺ : cation %) of the alkali metal is 20% or less.

(13) The optical glass according to any one of (1) to (12), wherein the content of Si ⁴⁺ is 0 to 10%, and the content of B ³⁺ is 0, expressed as % of cation (% by mole). ~15%, the content of Zn ²⁺ is 0~30%, the content of Nb ⁵⁺ is 0~10%, the content of Ti ⁴⁺ is 0~10%, and the content of Zr ⁴⁺ is 0~10. %, the content of Ta ⁵⁺ is 0 to 10%, the content of W ⁶⁺ is 0 to 10%, the content of Ge ⁴⁺ is 0 to 10%, and the content of Bi ³⁺ is 0 to 10%. The content of Te ⁴⁺ is 0 to 15%.

(14) The optical glass according to any one of (1) to (13), wherein the degree of wear under the measurement method of "JOGIS10-1994 Method for Measuring the Abrasion of Optical Glass" is 600 or less.

(15) An optical element comprising the optical glass of any one of (1) to (14).

(16) A preform for polishing processing and/or precision press molding, comprising the optical glass according to any one of (1) to (14).

(17) An optical element obtained by precisely pressurizing a preform of (16).

According to the present invention, it is possible to provide an optical glass, a preform using the same, and an optical element which can obtain optical characteristics such as desired imaging characteristics with high precision over a wider temperature range.

The optical glass of the present invention contains P ⁵⁺ , Al ³⁺ and Mg ²⁺ as a cationic component, and contains O ² and F ⁻ as an anion component, and the temperature coefficient (20 to 40° C.) of the relative refractive index (589.29 nm) is - 6.0×10 ^-6 (°C ^-1 ) or more. In addition to P ⁵⁺ , Al ³⁺ and Mg ^{2+ are} contained as a cationic component, and F ^{− is} contained as an anion component in addition to O ^{2 —} thereby increasing the temperature coefficient of the relative refractive index of the optical glass. Therefore, an optical glass which contributes to high resolution and miniaturization of an optical system can be obtained by obtaining optical characteristics such as desired imaging characteristics with high precision in a wider temperature range.

Hereinafter, such an optical glass is also referred to as "the optical glass of the present invention".

Hereinafter, the optical glass of the present invention will be described. The present invention is not limited to the following aspects, and can be implemented by appropriately changing the scope of the object of the present invention. In addition, the description of the overlapping description is omitted, but the gist of the invention is not limited.

<Glass composition>

The respective components constituting the optical glass of the present invention will be described.

In the present specification, the content of each component is referred to as the cation % or the anion % based on the molar ratio, unless otherwise specified. Here, "cation %" and "anion %" (hereinafter, the case where "cation % (mole %)" and "anion % (mole %)") are used: the glass of the optical glass of the present invention The constituent components were separated into a cationic component and an anionic component, and the total ratio was set to 100 mol%, and the composition of the content of each component contained in the glass was expressed.

Furthermore, the ion valence of each component is only a convenient value and a representative value is used, so it is not distinguished from other ion valences. The ion valence of each component present in the optical glass has a possibility other than the representative value. For example, P is usually present in the glass in a state in which the ionic value is pentad. Therefore, in the present specification, P is represented as "P ⁵⁺ ", but there is a possibility that it exists in the state of other ion valence. As such, strictly speaking, even if it exists in the state of other ion valence, it is considered in this specification that each component exists in glass in the ion value of a representative value.

[About cationic ingredients]

The optical glass of the present invention contains P ⁵⁺ . The content of P ⁵⁺ is preferably from 20 to 55%.

The P ⁵⁺ -based glass forming component has a property of suppressing devitrification of the glass and increasing the refractive index. Since such a property is gradually enhanced, the lower limit of the content ratio of P ⁵⁺ is preferably 20.0%, more preferably 25.0%, still more preferably 30.0%.

On the other hand, P ⁵⁺ has a property of lowering the Abbe number if the content ratio is high. This property is gradually enhanced, so the upper limit of the content of P ⁵⁺ is preferably 55.0%, more preferably 50.0%, still more preferably 45.0%, still more preferably 41.0%, still more preferably 37.0%.

P ⁵⁺ can be contained in the glass using Al(PO ₃ ) ₃ , Ca(PO ₃ ) ₂ , Ba(PO ₃ ) ₂ , Zn(PO ₃ ) ₂ , BPO ₄ , H ₃ PO ₄ or the like as a raw material.

The optical glass of the present invention contains Al ³⁺ . The content of Al ³⁺ is preferably from 1 to 20%.

Al ³⁺ has the property of improving the resistance to devitrification of the glass, reducing the degree of wear, and increasing the temperature coefficient of the relative refractive index. Such a property is gradually enhanced, so the lower limit of the content ratio of Al ³⁺ is preferably 1.0%, more preferably 5.0%, still more preferably 7.0%, still more preferably 9.7%.

On the other hand, Al ³⁺ has a property of lowering the refractive index of the glass if the content ratio is high. Since such a property is gradually enhanced, the upper limit of the content ratio of Al ³⁺ is preferably 20.0%, more preferably 18.0%, still more preferably 16.0%.

Al ³⁺ can be contained in the glass using Al(PO ₃ ) ₃ , AlF ₃ , Al ₂ O ₃ or the like as a raw material.

The optical glass of the present invention contains Mg ²⁺ . The content of Mg ²⁺ is preferably from 0.1 to 30%.

Mg ²⁺ has the property of improving the resistance to devitrification of glass, reducing the degree of wear, and increasing the temperature coefficient of relative refractive index. Such a property is gradually enhanced, so the lower limit of the content of Mg ²⁺ is preferably 0.1%, more preferably 2.0%, still more preferably 5.0%, still more preferably 10.0%, and still more preferably more than 11.0%. .

On the other hand, Mg ²⁺ has a property of lowering the refractive index of glass if the content ratio is high. Since such a property is gradually enhanced, the upper limit of the content of Mg ²⁺ is preferably 30.0%, more preferably 25.0%, still more preferably 20.0%.

Mg ²⁺ can be contained in the glass using MgO, MgF ₂ or the like as a raw material.

The optical glass of the present invention may also contain Ca ²⁺ as an optional component. The content of Ca ²⁺ is preferably 30% or less.

Ca ²⁺ has a property of improving the devitrification resistance of the glass, suppressing the decrease in the refractive index, lowering the degree of wear, and increasing the temperature coefficient of the relative refractive index. Since such a property is gradually enhanced, the lower limit of the content of Ca ²⁺ is preferably 0.1%, more preferably 5.0%, and further preferably more than 10.0%.

On the other hand, when Ca ²⁺ has a high content rate, the resistance to devitrification of the glass is lowered and the refractive index is lowered. Since such a property is gradually enhanced, the upper limit of the content of Ca ²⁺ is preferably 30.0%, more preferably 20.0%, still more preferably 16.0%.

Ca ²⁺ can be contained in the glass using Ca(PO ₃ ) ₂ , CaCO ₃ , CaF ₂ or the like as a raw material.

The optical glass of the present invention may further contain Sr ²⁺ as an optional component. The content of Sr ²⁺ is preferably 30% or less.

Sr ²⁺ has the property of improving the resistance to devitrification of the glass and suppressing the decrease in the refractive index. Since such a property is gradually enhanced, the lower limit of the content ratio of Sr ²⁺ may be preferably 0.1%, more preferably 1.0%, still more preferably 2.0%.

On the other hand, when Sr ²⁺ has a high content ratio, the devitrification resistance of the glass is lowered and the refractive index is lowered. Since such a property is gradually enhanced, the upper limit of the content ratio of Sr ²⁺ is preferably 30.0%, more preferably 20.0%, still more preferably 14.0%.

Sr ²⁺ can be contained in the glass using Sr(NO ₃ ) ₂ , SrF ₂ or the like as a raw material.

The optical glass of the present invention may further contain Ba ²⁺ as an optional component. The content of Ba ²⁺ is preferably 30% or less.

Ba ²⁺ has the property of improving the resistance to devitrification of the glass, maintaining low dispersibility, and increasing the refractive index. Since such a property is gradually enhanced, the lower limit of the content of Ba ²⁺ may be preferably 0.1%, more preferably 1.0%, still more preferably 5.0%, still more preferably 10.0%, still more preferably 12.0%. Further preferably, it is 14.0%.

On the other hand, Ba ²⁺ has a property of lowering the resistance to devitrification of the glass and lowering the temperature coefficient of the relative refractive index if the content is higher. Since such a property is gradually enhanced, the upper limit of the content of Ba ²⁺ is preferably 30.0%, more preferably 25.0%, still more preferably 20.0%, still more preferably 17.1% or less.

Ba ²⁺ can be contained in the glass using Ba(PO ₃ ) ₂ , BaCO ₃ , Ba(NO ₃ ) ₂ , BaF ₂ or the like as a raw material.

The alkaline earth metal in the present invention means one or more selected from the group consisting of Mg ²⁺ , Ca ²⁺ , Sr ²⁺ and Ba ²⁺ . Further, there is a case where one or more selected from the group consisting of Mg ²⁺ , Ca ²⁺ , Sr ^{2+ ,} and Ba ²⁺ is represented as R ²⁺ .

In addition, the total content ratio of R ²⁺ means a total content ratio of one or more of the four ions (for example, Mg ²⁺ + Ca ²⁺ + Sr ²⁺ + Ba ²⁺ ).

The total content of R ²⁺ is preferably from 30 to 70%. When the total content of R ²⁺ is in this range, a glass having higher devitrification resistance can be obtained.

The lower limit of the total content of R ²⁺ is preferably 30.0%, more preferably 35.0%, still more preferably 40.0%, still more preferably 44.0%. On the other hand, the upper limit of the total content of R ²⁺ is preferably 70.0%, more preferably 65.0%, still more preferably 60.0%, still more preferably 55.0%.

The optical glass of the present invention preferably has a total content of Mg ²⁺ and Ca ²⁺ of 7.5 to 50%. By having a high total content ratio, the temperature coefficient of the relative refractive index can be increased. Therefore, the lower limit of (Mg ²⁺ + Ca ²⁺ ) is preferably 7.5%, more preferably 12.5%, still more preferably 25.0%.

On the other hand, when the total content ratio is high, it has a property of lowering the devitrification resistance of the glass and lowering the refractive index. Such a property is gradually enhanced, so the upper limit of (Mg ²⁺ + Ca ²⁺ ) is preferably 50.0%, more preferably 40.0%, still more preferably 35.0%.

The optical glass of the present invention preferably has a ratio of the total content of Mg ²⁺ (cation %) and Ca ²⁺ content (cation %) to the total content of alkaline earth metals (R ²⁺ : cation %) ((Mg) ²⁺ + Ca ²⁺ ) / R ²⁺ ) is 0.25 or more.

The ratio of the total content of Mg ²⁺ and Ca ²⁺ to R ²⁺ is higher, whereby the temperature coefficient of the relative refractive index can be increased and the degree of wear can be lowered. Therefore, the lower limit of (Mg ²⁺ + Cg ²⁺ ) / R ²⁺ is preferably 0.25, more preferably 0.31, still more preferably 0.36, still more preferably 0.41, still more preferably 0.50.

On the other hand, the upper limit of (Mg ²⁺ + Ca ²⁺ ) / R ²⁺ may also be 1. However, when the ratio of the total content of Mg ²⁺ and Ca ²⁺ to R ²⁺ is high, it has a property of lowering the devitrification resistance of the glass and lowering the refractive index. Since such a property is gradually enhanced, the upper limit of (Mg ²⁺ + Ca ²⁺ ) / R ^{2+ can} be preferably 0.90, more preferably 0.80, still more preferably 0.70, still more preferably 0.65.

Further, the optical glass of the present invention preferably has a ratio of Mg ²⁺ content (cation %) to P ⁵⁺ content (cation %) (Mg ²⁺ /P ⁵⁺ ) of 0.25 or more.

By increasing the ratio of the content of Mg ²⁺ which is more effective in increasing the temperature coefficient of the relative refractive index to the content ratio of the glass forming component P ⁵⁺ , the temperature coefficient of the relative refractive index of the glass can be further increased. Therefore, the lower limit of (Mg ²⁺ /P ⁵⁺ ) is preferably 0.25, more preferably 0.30, still more preferably 0.35, still more preferably 0.42.

On the other hand, when the ratio of the content ratio of Mg ^{2+ to} the content ratio of P ⁵⁺ of the ratio is high, it has a property of lowering the devitrification resistance of the glass and lowering the refractive index. Since such a property is gradually enhanced, the upper limit of (Mg ²⁺ /P ⁵⁺ ) can be preferably 1.00, more preferably 0.90, still more preferably 0.80, still more preferably 0.70.

La ³⁺ , Gd ³⁺ , Y ³⁺ , Yb ^{3+ ,} and Lu ³⁺ have properties of maintaining low dispersibility, increasing refractive index, and further improving resistance to devitrification. In order to enhance such properties, the optical glass of the present invention may further comprise, as an optional component, one or more components selected from the group consisting of La ³⁺ , Gd ³⁺ , Y ³⁺ , Yb ^{3+ ,} and Lu ³⁺ .

On the other hand, the content ratios of La ³⁺ , Gd ³⁺ , Y ³⁺ , Yb ³⁺ and Lu ³⁺ are each preferably 10% or less. When La ³⁺ , Gd ³⁺ , Y ³⁺ , Yb ^{3+ ,} and Lu ³⁺ have a high content rate, the stability of the glass is deteriorated, and the property is easily devitrified. Such a property is gradually enhanced, so the upper limit of the respective contents of La ³⁺ , Gd ³⁺ , Y ³⁺ , Yb ³⁺ and Lu ³⁺ is preferably 10.0%, more preferably 8.0%, still more preferably 5.0. %, further preferably 3.0%.

La ^{3O 3} , Gd ³⁺ , Y ³⁺ , Yb ^{3+ ,} and Lu ³⁺ may be La ₂ O ₃ , LaF ₃ , Gd ₂ O ₃ , GdF ₃ , Y ₂ O ₃ , YF ₃ , Yb ₂ O ₃ , Lu ₂ O ₃ or the like is contained in the glass as a raw material.

Ln ³⁺ in the present invention means at least one selected from the group consisting of Y ³⁺ , La ³⁺ , Gd ³⁺ , Yb ^{3+ ,} and Lu ³⁺ . In addition, the total content ratio of Ln ³⁺ means the total content ratio of these five ions (Y ³⁺ + La ³⁺ + Gd ³⁺ + Yb ³⁺ + Lu ³⁺ ).

In the optical glass of the present invention, the total content of Ln ³⁺ is preferably 20% or less. Ln ³⁺ has a property of being easily devitrified if the content rate is high. The above-described property is gradually increased. Therefore, the upper limit of the total content of Ln ³⁺ is preferably 20.0%, more preferably 15.0%, still more preferably 10.0%, still more preferably 5.0%, still more preferably 3.0%. The total content of Ln ³⁺ may be set to be less than 2.0%, or may be set to less than 1.0%. Further, since Ln ³⁺ is an optional component, the optical glass of the present invention may not contain Ln ³⁺ .

Li ⁺ , Na ⁺ and K ⁺ have properties of maintaining devitrification resistance at the time of glass formation and lowering the glass transition point (Tg). In order to enhance such properties, the optical glass of the present invention may further comprise one or more selected from the group consisting of Li ⁺ , Na ⁺ and K ⁺ as an optional component.

On the other hand, the content of Li ⁺ is preferably 20% or less, and the content of Na ⁺ and K ⁺ is preferably 10% or less. Li ⁺ , Na ⁺ and K ⁺ have a property that the abrasion rate of the glass is increased and the chemical durability is deteriorated if the content ratio is high. Since such a property is gradually enhanced, the upper limit of the content of Li ⁺ is preferably 20.0%, more preferably 15.0%, still more preferably 10.0%. Further, the upper limit of the content ratio of Na ⁺ and K ⁺ is preferably 10.0%, more preferably 8.0%, still more preferably 5.0%.

As Li ⁺ , Na ⁺ and K ^{+ ,} Li ₂ CO ₃ , LiNO ₃ , LiF, Na ₂ CO ₃ , NaNO ₃ , NaF, Na ₂ SiF ₆ , K ₂ CO ₃ , KNO ₃ , KF, KHF ₂ , K _{2 may be used.} SiF ₆ or the like is contained in the glass as a raw material.

In the present invention, Rn ⁺ means at least one selected from the group consisting of Li ⁺ , Na ⁺ and K ⁺ . In addition, the total content ratio of Rn ⁺ means the total content ratio of these three ions (Li ⁺ + Na ⁺ + K ⁺ ).

In the optical glass of the present invention, the total content of Rn ⁺ is preferably 20% or less. When the total content of Rn ⁺ is high, the degree of abrasion of the glass is increased and the chemical durability is deteriorated. Since such a property is gradually enhanced, the upper limit of the total content of Rn ⁺ is preferably 20.0%, more preferably 15.0%, still more preferably 10.0%.

Si ⁴⁺ has the property of improving the resistance to devitrification of the glass, increasing the refractive index, and reducing the wear. Therefore, the optical glass of the present invention may contain Si ⁴⁺ as an optional component.

On the other hand, the content of Si ⁴⁺ is preferably 10% or less. Si ⁴⁺ has a property that the glass is easily devitrified if the content ratio is high. Since such a property is gradually enhanced, the upper limit of the content ratio of Si ⁴⁺ is preferably 10.0%, more preferably 8.0%, still more preferably 5.0%.

Si ⁴⁺ can be contained in the glass using SiO ₂ , K ₂ SiF ₆ , Na ₂ SiF ₆ or the like as a raw material.

B ³⁺ has the property of improving the resistance to devitrification of the glass, increasing the refractive index, and reducing the wear. Therefore, the optical glass of the present invention may also contain B ³⁺ as an optional component.

On the other hand, the content of B ³⁺ is preferably 15% or less. B ³⁺ has a property of deteriorating chemical durability if the content ratio is high. Such a property is gradually enhanced, so the upper limit of the content of B ³⁺ is preferably 15.0%, more preferably 8.0%, still more preferably 5.0%, still more preferably 3.0%.

B ³⁺ can be contained in the glass using H ₃ BO ₃ , Na ₂ B ₄ O ₇ , BPO ₄ or the like as a raw material.

Zn ²⁺ has the property of improving the resistance to devitrification of glass. Therefore, the optical glass of the present invention may further contain Zn ²⁺ as an optional component.

On the other hand, the content of Zn ²⁺ is preferably 30% or less. Zn ²⁺ has a property that the wear rate of the glass is deteriorated and the refractive index is lowered if the content ratio is high. Such a property is gradually enhanced, so the upper limit of the content of Zn ²⁺ is preferably 30.0%, more preferably 12.0%, still more preferably 8.0%, still more preferably 4.0%, still more preferably 2.0%.

Zn ²⁺ can be contained in the glass using Zn(PO ₃ ) ₂ , ZnO, ZnF ₂ or the like as a raw material.

Nb ⁵⁺ , Ti ⁴⁺ and W ⁶⁺ have properties of increasing the refractive index of the glass. In addition, Nb ⁵⁺ has the property of improving chemical durability, and W ⁶⁺ has the property of lowering the transfer point of the glass. Therefore, the optical glass of the present invention may further contain one or more selected from the group consisting of Nb ⁵⁺ , Ti ⁴⁺ and W ⁶⁺ as an optional component.

On the other hand, the content ratio of Nb ⁵⁺ , Ti ⁴⁺ and W ⁶⁺ is preferably 10% or less. Nb ⁵⁺ , Ti ⁴⁺ and W ⁶⁺ have the property of lowering the Abbe number if the content ratio is high. Further, Ti ⁴⁺ and W ⁶⁺ have a property of coloring the glass if the content ratio is high. Since such a property is gradually enhanced, the upper limit of the respective contents of the contents of Nb ⁵⁺ , Ti ⁴⁺ and W ⁶⁺ is preferably 10.0%, more preferably 8.0%, still more preferably 5.0%.

Nb ⁵⁺ , Ti ⁴⁺ and W ⁶⁺ can be contained in the glass using Nb ₂ O ₅ , TiO ₂ , WO ₃ or the like as a raw material.

Zr ⁴⁺ has the property of increasing the refractive index of the glass. Therefore, the optical glass of the present invention may further contain Zr ⁴⁺ as an optional component.

On the other hand, the content of Zr ⁴⁺ is preferably 10% or less. Zr ⁴⁺ has a property of generating streaks due to volatilization of components in the glass if the content ratio is high. Since such a property is gradually enhanced, the upper limit of the content ratio of Zr ⁴⁺ is preferably 10.0%, more preferably 8.0%, still more preferably 5.0%.

Zr ⁴⁺ can be contained in the glass using ZrO ₂ , ZrF ₄ or the like as a raw material.

Ta ⁵⁺ has the property of increasing the refractive index of the glass. Therefore, the optical glass of the present invention may further contain Ta ⁵⁺ as an optional component.

On the other hand, the content of Ta ⁵⁺ is preferably 10% or less. Ta ⁵⁺ has a property that the glass is easily devitrified if the content rate is high. Since such a property is gradually enhanced, the upper limit of the content of Ta ⁵⁺ is preferably 10.0%, more preferably 8.0%, still more preferably 5.0%.

Ta ⁵⁺ can be contained in the glass using Ta ₂ O ₅ or the like as a raw material.

Ge ⁴⁺ has the property of increasing the refractive index of the glass and improving the resistance to devitrification. Therefore, the optical glass of the present invention may further contain Ge ⁴⁺ as an optional component.

On the other hand, the content of Ge ⁴⁺ is preferably 10% or less. If the content of Ge ⁴⁺ is high, the material cost of the glass increases. Therefore, the upper limit of the content ratio of Ge ⁴⁺ is preferably 10.0%, more preferably 8.0%, still more preferably 5.0%.

Ge ⁴⁺ can be contained in the glass using GeO ₂ or the like as a raw material.

Bi ³⁺ and Te ⁴⁺ have the property of increasing the refractive index of the glass and lowering the transfer point of the glass. The optical glass of the present invention may also contain Bi ³⁺ or Te ⁴⁺ as an optional component.

On the other hand, the content of Bi ³⁺ is preferably 10% or less, and the content of Te ⁴⁺ is preferably 15% or less. Bi ³⁺ and Te ⁴⁺ have a property of coloring the glass and devitrifying it easily if the content ratio is high. Since such a property is gradually enhanced, the upper limit of the content of Bi ³⁺ is preferably 10.0%, more preferably 8.0%, still more preferably 5.0%. Further, the upper limit of the content ratio of Te ⁴⁺ is preferably 15.0%, more preferably 10.0%, still more preferably 8.0%, still more preferably 5.0%.

Bi ³⁺ and Te ⁴⁺ can be contained in the glass using Bi ₂ O ₃ , TeO ₂ or the like as a raw material.

[About anionic ingredients]

The optical glass of the present invention contains F ^- . The content of F ^- is preferably from 20 to 70%.

F ^- has the property of increasing the abnormal dispersibility of the glass and the Abbe number so that the glass is not easily devitrified. Such a property is gradually enhanced, so the lower limit of the content ratio of F ^- is preferably 20.0%, more preferably 30.0%, still more preferably 35.0%, still more preferably 38.0%.

On the other hand, F ^- if the content has a higher Abbe number of the glass is excessively increased, the decrease of the degree of wear properties. Such a property is gradually enhanced, so the lower limit of the content ratio of F ^- is preferably 70.0%, more preferably 60.0%, still more preferably 50.0%, still more preferably 48.0%.

F ^- may be used AlF _3, MgF _2, BaF ₂ and other fluoride as a raw material of the cationic component contained in the glass.

The optical glass of the present invention contains O ^2- . The content of O ^2- is preferably from 30 to 80%.

O ^2- has a property of suppressing devitrification of the glass and suppressing an increase in the degree of wear. Such a property is gradually enhanced, so the lower limit of the content of O ^2- is preferably 30.0%, more preferably 40.0%, still more preferably 45.0%, still more preferably 50.0%.

On the other hand, in order to easily obtain the effect by other anionic components, the upper limit of the content ratio of O ² is more preferably 80.0%, more preferably 70.0%, still more preferably 66.0%, still more preferably 62.0. %.

Further, from the viewpoint of suppressing devitrification of the glass, the total content of O ^{2 and} the content of F ^- is preferably 98.0%, more preferably 99.0%, and further preferably 100%. .

O ² can be used as a raw material by using an oxide of various cationic components such as Al ₂ O ₃ , MgO or BaO, or a phosphate of various cationic components such as Al(PO) ₃ , Mg(PO) ₂ or Ba(PO) ₂ . In the glass.

[About other ingredients]

In the optical glass of the present invention, other components may be added as needed within the range which does not impair the characteristics of the glass of the present invention.

[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 suitable for inclusion will be described.

In addition to Ti, Zr, Nb, W, La, Gd, Y, Yb, and Lu, cations of transition metals such as V, Cr, Mn, Fe, Co, Ni, Cu, Ag, and Mo have the following properties: even alone or When a small amount of the composite is contained in a small amount, the glass is colored and absorbed at a specific wavelength in the visible light region. Therefore, it is preferable that the optical glass having a wavelength of the visible light region is substantially free of such.

The cations of Pb, Th, Cd, Tl, Os, Be, and Se have been used in recent years as a harmful chemical substance, and it is considered that not only the manufacturing steps of the glass but also the processing steps and the processing after the product are considered to be necessary. Measures on the policy. Therefore, when it is important to pay attention to the influence of the environment, it is preferable that it is substantially excluded from the inevitable mixing. Thereby, the optical glass is substantially free of substances that pollute the environment. Therefore, the optical glass can be manufactured, processed, and disposed of without taking special measures for environmental measures.

The cation of Sb or Ce is useful as an antifoaming agent, but as a component which adversely affects the environment, there has been a tendency to be excluded from optical glass in recent years. Therefore, in view of the above, the optical glass of the present invention is preferably free of Sb or Ce.

[Production method]

The method for producing the optical glass of the present invention is not particularly limited. For example, it can be produced by uniformly mixing the raw materials so that the respective components are within a specific content range, and putting the prepared mixture into quartz crucible or alumina crucible or platinum crucible for partial melting. Adding to platinum rhodium, platinum alloy rhodium or ruthenium, melting in the temperature range of 900~1200 °C for 2~10 hours, stirring to homogenize and defoaming, etc., then lowering to a temperature below 850 °C The streaks are removed by completion of the agitation and cast into a mold for slow cooling.

[physical property]

The optical glass of the present invention has a relatively high temperature coefficient of relative refractive index (dn/dT). More specifically, the lower limit of the temperature coefficient (20 to 40 ° C) of the relative refractive index (589.29 nm) of the optical glass of the present invention is preferably -6.0 × 10 ^-6 ° C ^-1 , more preferably -5.5 × 10 ^{- 6} ° C ^-1 , further preferably -5.0 × 10 ^-6 ° C ^-1 . As a result, even in an environment where the temperature of the optical element greatly changes, the variation in the refractive index is reduced, so that the desired optical characteristics can be exhibited with high precision over a wider temperature range.

On the other hand, if the temperature coefficient of the relative refractive index is excessively large in the positive direction, the change in the refractive index caused by the temperature change of the optical element becomes large. Therefore, the upper limit of the temperature coefficient of the relative refractive index of the optical glass of the present invention may be preferably 6.0 × 10 ^-6 ° C ^-1 , more preferably 5.5 × 10 ^-6 ° C ^-1 , still more preferably 5.0. ×10 ^-6 °C ^-1 . The optical glass of the present invention preferably has a lower absolute value of the relative temperature coefficient of the refractive index, and is preferably 0.

Further, regarding the temperature coefficient of the relative refractive index, the temperature of the optical glass is changed while irradiating the light having a wavelength of 589.29 nm in the same temperature as the optical glass, and the temperature coefficient of the relative refractive index is an average temperature of 1 ° C at this time. The amount of change in refractive index (×10 ^-6 /°C) is expressed.

The optical glass of the present invention is not particularly limited as long as it is a fluorophosphate glass containing P ⁵⁺ and F ^- , and particularly preferably has a high refractive index (nd) and a low dispersibility ( Higher Abbe number).

The optical glass of the present invention preferably has a refractive index (nd) of 1.50 or more and 1.60 or less. More specifically, the lower limit of the refractive index of the optical glass of the present invention is preferably 1.50, more preferably 1.51, still more preferably 1.52. Further, the upper limit of the refractive index of the optical glass of the present invention is preferably 1.58, more preferably 1.57, still more preferably 1.55.

The optical glass of the present invention preferably has an Abbe number ( ν d) of 60 or more and 80 or less. More specifically, the lower limit of the Abbe number of the optical glass of the present invention is preferably 60, more preferably 65, still more preferably 70, still more preferably 73. On the other hand, the upper limit of the Abbe number of the optical glass of the present invention is preferably 80, more preferably 78, still more preferably 77.

As a result, the degree of freedom in optical design is increased, and even if the thickness of the element is reduced, the amount of refraction of the light required can be obtained. Therefore, the optical system can be made more precise and smaller.

Further, the refractive index (nd) and the Abbe number (νd) mean values obtained by measurement based on the Japanese Optical Glass Industry Association specification JOGIS01-2003.

The lower the degree of wear of the optical glass of the present invention, the better. As a result, abrasion or damage other than necessary for the optical glass is reduced, and the operation in the polishing process of the optical glass is facilitated, so that the polishing process can be easily performed. The upper limit of the abrasion of the optical glass of the present invention is preferably 600, more preferably 550, still more preferably 500, still more preferably 450, and still more preferably 430.

On the other hand, if the abrasion degree is too low, it tends to be difficult to perform the polishing process. Therefore, the lower limit of the abrasion degree of the optical glass of the present invention may be preferably 80, more preferably 100, still more preferably 120.

In addition, the abrasion degree means the value obtained by the measurement of the "method of measuring the abrasion degree of the optical glass of JOGIS10-1994."

[Preforms and optical components]

The optical glass of the present invention is useful in various optical elements and optical designs. Among them, it is particularly preferable to produce an optical element such as a lens, a iridium, or a mirror by using a method of forming a preform from the optical glass of the present invention, and pre-forming the preform The formed body is subjected to grinding processing or precision press forming. Thereby, high-definition and high-precision imaging characteristics can be realized when used in an optical machine such as a camera or a projector that allows visible light to penetrate the optical element. In particular, the optical glass of the present invention has a small change in refractive index caused by a change in temperature, and thus, for example, It can be used in high-temperature applications such as projectors, and it can achieve high-definition and high-precision imaging characteristics. Here, the method of producing the preform material is not particularly limited, and for example, a method of forming a glass blank described in Japanese Patent Laid-Open No. Hei 8-319124, or an optical glass as described in Japanese Patent Laid-Open No. Hei 8-73229 A method of directly producing a preform material from molten glass like a manufacturing method and a manufacturing apparatus. Further, a method of performing cold working such as grinding and polishing on a strip material formed of optical glass may be used.

[Examples]

The optical glass of the present invention, that is, the compositions of the glasses of Examples 1 to 3 and Comparative Example 1 (indicated by % of cation or % of mol representing anion %), refractive index (nd), Abbe number (νd), and relative The temperature coefficient (dn/dT) and the degree of wear (Aa) of the refractive index are shown in Table 1. Furthermore, the following examples are for illustrative purposes only and are not limited to the embodiments.

The optical glasses of Examples 1 to 3 and Comparative Example 1 of the present invention were produced by using the respective oxides, carbonates, nitrates, fluorides, metaphosphoric compounds, and the like as raw materials for the respective components. The high-purity raw material of the fluorophosphate glass is weighed and uniformly mixed so as to have the composition ratio of each of the examples shown in Table 1, and then put into a platinum crucible, and the electric furnace is used according to the melting difficulty of the glass composition. After melting in the temperature range of 900 to 1200 ° C for 2 to 10 hours, stirring to homogenize and defoaming, etc., the temperature is lowered to 850 ° C or less, and then cast into a mold to perform slow cooling to produce glass.

Here, the refractive indices (nd) of the optical glasses of Examples 1 to 3 and Comparative Example 1 and The Abbe number (νd) is measured based on the Japanese Optical Glass Industry Association specification JOGIS01-2003. In addition, as the glass used for the measurement, the annealing conditions were such that the slow cooling reduction rate was -25 ° C / hr and the treatment was carried out in a slow cooling furnace.

Further, the temperature coefficients (dn/dT) of the relative refractive indices of the optical glasses of Examples 1 to 3 and Comparative Example 1 are based on the Japanese Optical Glass Industry Association specification JOGIS18-1994 "Method for Measuring the Temperature Coefficient of Refractive Index of Optical Glass" The interference method in the method described is measured.

Further, the degree of wear was measured in accordance with "JOGIS10-1994 Method for Measuring the Abrasion of Optical Glass". That is, a sample of a glass square plate of 30×30×10 mm size is placed at a starting position of 80 mm from the center of a cast iron flat plate (250 mmΦ) rotated horizontally 60 times per minute, and 9.8 N is applied vertically. (1 kgf) load, in the same way, add #800 (average particle size 20 μm) of abrasive material (alumina A abrasive grain) 10 g of slurry to 20 mL of water for 5 minutes to rub The mass of the sample before and after the polishing was measured, and the abrasion quality was determined. The wear quality of the standard sample specified by the Japan Optical Glass Industry Association was obtained in the same manner and calculated according to the following formula: wear rate = {(wear quality/specific gravity of the sample) / (wear quality/specific gravity of the standard sample) }×100.

As shown in Table 1, the temperature coefficient (20 to 40 ° C) of the relative refractive index of the optical glasses of Examples 1 to 3 of the present invention was -6.0 × 10 ^-6 ° C ^-1 or more, which was within the desired range. On the other hand, in Comparative Example 1 other than the range of the present invention, the temperature coefficient of the relative refractive index was lower than -6.0 × 10 ^-6 ° C ^-1 . Therefore, it is understood that the optical glass of the embodiment of the present invention has a higher temperature coefficient of relative refractive index than the glass of Comparative Example 1.

Further, the refractive index of the optical glass of the embodiment of the present invention is 1.50 or more, and more specifically 1.53 or more, which is within a desired range. Further, the optical glass Abbe number of the embodiment of the present invention is 60 or more, and more specifically 74 or more, which is within a desired range. Further, the optical glass abrasion degree of the embodiment of the present invention is 600 or less, which is within the required range.

Therefore, it is clear that the refractive index and the Abbe number of the optical glass of the embodiment of the present invention are within a desired range, the temperature coefficient of the relative refractive index is high, and the degree of wear is small. From this, it is presumed that the optical glass of the embodiment of the present invention can obtain optical characteristics such as desired imaging characteristics with high precision over a wider temperature range, thereby contributing to high resolution and miniaturization of the optical system.

Further, the optical glass of the embodiment of the present invention is subjected to grinding and polishing after forming a preform for polishing, and is processed into a shape of a lens and a crucible. Further, the optical glass of the embodiment of the present invention is used to form a preform for precision press molding, and the preform is subjected to precision press forming to be processed into a shape of a lens and a crucible. In either case, it can be processed into various lenses and shapes.

The present invention has been described in detail above with reference to the preferred embodiments of the invention.

Claims (13)

An optical glass, represented by cationic % (% by mole), containing P ^{5+ 20-55} %, Al ³⁺ 1-20%, Mg ²⁺ 10.0-30%, Ca ²⁺ 0.1-30%, Sr ^{2 +} 0.1~30% and Ba ²⁺ 0.1~30% as cationic component, expressed as anion % (mol%), containing O ² 30~80% and F ^- 20~70% as anion components, and relative refractive index The temperature coefficient (20 to 40 ° C) of (589.29 nm) is -6.0 × 10 ^-6 (°C ^-1 ) or more, and the ratio of Mg ²⁺ content (cation %) to P ⁵⁺ content (cation %) (Mg ²⁺ /P ⁵⁺ ) is 0.44 or more. The optical glass of claim 1, wherein the total content of the alkaline earth metals (R ²⁺ : cation %) is 30 to 70%. The optical glass of claim 1, wherein the total amount of Mg ²⁺ and Ca ²⁺ (cation %) is 12.5 to 50%. The optical glass of claim 2, wherein the ratio of the Mg ²⁺ content and the total content of Ca ^{2+ to} the total content of the alkaline earth metal (R ²⁺ : cation %) ((Mg ²⁺ + Ca ²⁺ ) / R ²⁺ ) is 0.25 or more. The optical glass of claim 1, wherein the content of La ³⁺ is 0 to 10%, the content of Gd ³⁺ is 0 to 10%, and the content of Y ³⁺ is represented by % of cation (% by mole). 0 to 10%, the content of Yb ³⁺ is 0 to 10%, and the content of Lu ³⁺ is 0 to 10%. The optical glass of claim 5, wherein a total content ratio (Ln ³⁺ : cationic %) of La ³⁺ , Gd ³⁺ , Y ³⁺ , Yb ³⁺ and Lu ³⁺ is 0 to 20%. The optical glass of claim 1, wherein the content of Li ⁺ is 0 to 20%, the content of Na ⁺ is 0 to 10%, and the content of K ⁺ is 0 to 10, expressed as % of cation (% by mole). %. The optical glass of claim 7, wherein the total content of the alkali metals (Rn ⁺ : cationic %) is 20% or less. The optical glass of claim 1, wherein the content of Si ⁴⁺ is 0 to 10%, the content of B ³⁺ is 0 to 15%, and the content of Zn ²⁺ is represented by % of cation (% by mole). 0~30%, the content of Nb ⁵⁺ is 0~10%, the content of Ti ⁴⁺ is 0~10%, the content of W ⁶⁺ is 0~10%, and the content of Zr ⁴⁺ is 0~ 10%, the content of Ta ⁵⁺ is 0 to 10%, the content of Ge ⁴⁺ is 0 to 10%, the content of Bi ³⁺ is 0 to 10%, and the content of Te ⁴⁺ is 0 to 15%. . The optical glass of claim 1, wherein the abrasion degree under the measurement method of "JOGIS10-1994 optical glass abrasion degree measurement method" is 600 or less. An optical element comprising the optical glass of any one of claims 1 to 10. A preform for polishing processing and/or precision press forming, comprising the optical glass according to any one of claims 1 to 10. An optical element formed by precision pressing a preform of claim 12.