TW202030163A - Optical glass and optical element - Google Patents

Abstract

The invention aims to provide an optical glass. The characteristics of the optical glass barely change even if the melting time is long. The provided optical glass at least comprises F- and Al3+. The ratio of F-/Al3+ is 3.0 or greater. When the optical glass is melted at a given temperature, the variable quantities of nd, vd, Pg, F, D, and ng-nF in a unit time are extremely low. The components of the optical glass preferably meet a formula: O2-/(P5++Ti4++Nb5++W6+) ≥ 3.0.

Description

Optical glass and optical components

The present invention relates to optical glass and optical elements including the optical glass.

The conventional optical glass system puts raw materials into a melting furnace and melts them, and then pours them into a mold for pot melting. However, at present, continuous melting manufacturing which can continuously manufacture optical glass is the mainstream.

The advantage of continuous melting is that the residence time is constant and there is no difference between the tanks, so it is easy to adjust the glass characteristics to a constant.

However, depending on the composition of the glass, the characteristics of the glass tend to change even by continuous melting. For example, in the case where a glass component that is easily volatilized is included, as the melting time becomes longer, volatilization occurs and the composition changes, thereby causing the glass characteristics to vary.

In particular, although fluorophosphate glass has excellent optical properties, it exhibits significant volatility during the high temperature process of melting and molding the glass. During the melting and forming process, the volatilization caused by the melting of the glass may be the cause of the deterioration of the glass, the change of the optical characteristics, and the decrease of the uniformity of the glass.

Patent Document 1 describes a glass composition that suppresses fluctuations in glass characteristics, but a technology capable of suppressing fluctuations in glass characteristics for a longer period of time is desired. [Prior Technical Literature]

[Patent Document 1] JP 2007-76958 A

[The problem to be solved by the invention]

Therefore, the object of the present invention is to provide an optical glass with little variation in various characteristics of the glass even if the melting time is long. [Technical means to solve the problem]

As a result of intensive research, the inventors have found that, with a predetermined composition, the obtained glass has a small change in its characteristic value with the melting time, thus completing the present invention. That is, the present invention is as follows. [1] An optical glass, comprising at least F ^- and Al ³⁺ and F ^- / Al ³⁺ in 3.0 above, when molten at a predetermined temperature, the amount of change in the absolute value of nd (the amount of change per hour) is less than 0.00050. [2] For the optical glass described in [1], Pg and F of the aforementioned optical glass satisfy the following formula (1): Pg, F> −0.0004νd+0.5718...(1). [3] The optical glass as described in [1] or [2], comprising at least one component selected from the group consisting of Ti ⁴⁺ , Nb ⁵⁺ and W ⁶⁺ . [4] The optical glass according to any one of [1] to [3], wherein O ^2- /(P ⁵⁺ +Ti ⁴⁺ +Nb ⁵⁺ +W ⁶⁺ ) is 3.0 or more. [5] An optical glass, comprising at least F ^- and Al ³⁺ and F ^- / Al ³⁺ in 3.0 above, when molten at a predetermined temperature, the absolute value of the change amount νd (change amount per hour) is less than 1.50. [6] The optical glass as described in [5], wherein Pg and F of the aforementioned optical glass satisfy the following formula (1): Pg, F> −0.0004νd+0.5718...(1). [7] The optical glass as described in [5] or [6], comprising at least one component selected from the group consisting of Ti ⁴⁺ , Nb ⁵⁺ and W ⁶⁺ . [8] The optical glass according to any one of [5] to [7], wherein O ^2- /(P ⁵⁺ +Ti ⁴⁺ +Nb ⁵⁺ +W ⁶⁺ ) is 3.0 or more. [9] An optical glass, comprising at least F ^{- 3+} and F, and Al ^- / 3.0 or more, when molten at a predetermined temperature, Pg, F is the amount of change (amount of change per hour) Al ³⁺ absolute The value is less than 0.0025. [10] The optical glass as described in [9], wherein Pg and F of the aforementioned optical glass satisfy the following formula (1): Pg, F> −0.0004νd+0.5718...(1). [11] The optical glass as described in [9] or [10], comprising at least one component selected from the group consisting of Ti ⁴⁺ , Nb ⁵⁺ and W ⁶⁺ . [12] The optical glass according to any one of [9] to [11], wherein O ^2- /(P ⁵⁺ +Ti ⁴⁺ +Nb ⁵⁺ +W ⁶⁺ ) is 3.0 or more. [13] An optical glass, comprising at least F ^- and Al ³⁺ and F ^- / Al ³⁺ in 3.0 above, when molten at a predetermined temperature, mass changes from zero to 90 minutes is less than 1.5%. [14] The optical glass as described in [13], wherein Pg and F of the aforementioned optical glass satisfy the following formula (1): Pg, F> −0.0004νd+0.5718...(1). [15] The optical glass as described in [13] or [14], comprising at least one component selected from the group consisting of Ti ⁴⁺ , Nb ⁵⁺ and W ⁶⁺ . [16] The optical glass according to any one of [13] to [15], wherein O ^2- /(P ⁵⁺ +Ti ⁴⁺ +Nb ⁵⁺ +W ⁶⁺ ) is 3.0 or more. [17] An optical glass, comprising at least F ^- and Al ³⁺ and F ^- / Al ³⁺ in 3.0 above, when molten at a predetermined temperature, the amount of change D (nF-nC) of the variation amount (per hour The absolute value of) is less than 0.00015. [18] The optical glass described in [17], wherein Pg and F of the aforementioned optical glass satisfy the following formula (1): Pg, F> −0.0004νd+0.5718 (1). [19] The optical glass as described in [17] or [18], comprising at least one component selected from the group consisting of Ti ⁴⁺ , Nb ⁵⁺ and W ⁶⁺ . [20] The optical glass according to any one of [17] to [19], wherein O ^2- /(P ⁵⁺ +Ti ⁴⁺ +Nb ⁵⁺ +W ⁶⁺ ) is 3.0 or more. [21] An optical glass, comprising at least F ^{- 3+} and F, and Al ^- / 3.0 or more, when molten at a predetermined temperature, the amount of change in ng-nF (changes per hour) Al ³⁺ absolute The value is less than 0.00010. [22] The optical glass as described in [21], wherein Pg and F of the aforementioned optical glass satisfy the following formula (1): Pg, F> −0.0004νd + 0.5718...(1). [23] The optical glass as described in [21] or [22], comprising at least one component selected from the group consisting of Ti ⁴⁺ , Nb ⁵⁺ and W ⁶⁺ . [24] The optical glass according to any one of [21] to [23], wherein O ^2- /(P ⁵⁺ +Ti ⁴⁺ +Nb ⁵⁺ +W ⁶⁺ ) is 3.0 or more. [25] An optical element comprising the optical glass described in any one of [1] to [24]. [Effects of the invention]

In the optical glass of the present invention, various characteristics of the glass change little by melting.

Hereinafter, the present invention will be described, but the present invention is not limited to the mode for carrying out the invention.

First, the characteristics of the glass of the present invention and the composition of the optical glass will be explained. In the present specification, the content and the total content of the cationic component, unless otherwise specified, cationic% (cation%) represents, and the anion component (in the present specification is ^{O 2-, F -, Cl -} , Br -, I ^-) of content as well as content, unless otherwise indicated, expressed as anion% (anion%). Here, the cation% is a value calculated by "(number of cations of interest/total number of cations of the glass component)×100", and means the molar percentage of the amount of cations of interest to the total amount of cation components. In addition, the anion% is a value calculated by "(number of anions of interest/total anions of the glass component)×100", and means the molar percentage of the amount of anions of interest to the total amount of anion components.

The content ratio of the cation components is equal to the content ratio represented by the cationic component of interest, and the content ratio of the anion components is equal to the content ratio of the anion component of interest.

The ratio of the content of the cation component to the content of the anion component is calculated from the molar ratio (the molar ratio of each atom when the sum of cations and anions is 100). For example, in the case of O ^2- /P ⁵⁺ , when the total of cations and anions is 100, it is calculated using the ratio of P ^{5+ and} the ratio of O ^2- at this time. The ratio of the content of the cation component to the content of the anion component is calculated from the ratio shown in Table 2 in the examples.

In addition, the content of glass constituents can be quantified by known methods, such as inductively coupled plasma emission spectrometry (ICP-AES), inductively coupled plasma mass spectrometry (ICP-MS), and the like. In the present invention, the content of the glass constituents of 0% means that the constituents are not substantially contained, and that the constituents at the level of unavoidable impurities are allowed to be contained.

The refractive index of each wavelength is measured to the sixth place after the decimal point in accordance with the Japanese Industrial Standard JIS B 7071, and is expressed in the fifth place after the decimal point. The main dispersion is nF-nC (in this specification, nF-nC can be expressed as "D"), and ng-nF is also expressed with the fifth decimal place. Therefore, the changes of nd, D, and ng-nF are represented by the fifth decimal place. The Abbe number νd is expressed in the second digit after the decimal point, and the change in the Abbe number is also expressed in the second digit after the decimal point. Pg, F are represented by the fourth digit after the decimal point, and the change of Pg, F is also represented by the fourth digit after the decimal point.

[Optical Glass Features] In this specification, unless otherwise specified, the standard values of nd, νd, Pg, F, D, and ng-nF of the optical glass are values with a melting time of 1.5 hours. When checking the amount of change per unit time, it is calculated from the value at 2 hours of melting and the value at 4 hours of melting.

The refractive index nd of the optical glass of the present invention is not particularly limited, and the lower limit may be 1.30000 or more, 1.40000 or more, 1.50000 or more, 1.60000 or more, 1.70000 or more, 1.80000 or more, 1.90000 or more, 2.00000 or more, 2.10000 or more, or 2.20000 or more. The upper limit of the refractive index nd is 2.70000 or less, 2.60000 or less, 2.50000 or less, 2.40000 or less, 2.30000 or less, 2.20000 or less, 2.10000 or less, 2.0000 or less, 1.90000 or less, 1.80000 or less, 1.70000 or less, 1.60000 or less, 1.50000 or less, 1.40000 or less It is also possible.

As one of the characteristics of the optical glass of the present invention, the value of nd hardly changes regardless of the melting time. Specifically, the absolute value of the amount of change (the amount of change per hour) of nd at a predetermined temperature is less than 0.00050. If the amount of change in nd is less than 0.00050, even if the melting time changes for some reason in the manufacturing process, an optical glass having nd in the desired range can be obtained, and the yield can be improved. The preferred upper limit of the absolute value of the change amount of nd (the change amount per hour) may be, for example, less than 0.00040, less than 0.00030, less than 0.00020, less than 0.00010, and less than 0.00005.

The Abbe number νd of the optical glass of the present invention is not particularly limited, and the lower limit may be 10.00 or more, 15.00 or more, 20.00 or more, 25.00 or more, 30.00 or more, 35.00 or more, 40.00 or more, 45.00 or more, 50.00 or more, 55.00 or more, 60.00 Above, 65.00 or above, 70.00 or above, 75.00 or above, 80.00 or above, 85.00 or above, 90.00 or above, 95.00 or above, and 100.00 or above are also acceptable. The upper limit of the Abbe number νd may be 150.00 or less, 140.00 or less, 130.00 or less, 120.00 or less, 110.00 or less, 100.00 or less, 95.00 or less, 90.00 or less, 85.00 or less, 80.00 or less, 75.00 or less, 70.00 or less, 65.00 or less, 60.00 Below, 55.00 or less, 50.00 or less, 45.00 or less, 40.00 or less, 35.00 or less, 30.00 or less, 25.00 or less, or 20.00 or less.

As one of the characteristics of the optical glass of the present invention, the value of νd hardly changes regardless of the melting time. Specifically, the absolute value of the amount of change in νd (the amount of change per hour) is less than 1.50. If the amount of change in νd is less than 1.50, even if the melting time fluctuates for some reason in the manufacturing process, an optical glass having νd within a desired range can be obtained, and the yield can be improved. The preferred upper limit of the absolute value of the change in νd (the change per hour) can be, for example, less than 1.40, less than 1.30, less than 1.20, less than 1.10, less than 1.00, less than 0.90, less than 0.80, less than 0.70, less than 0.60, less than 0.50, Less than 0.40, less than 0.30, less than 0.20, and less than 0.10.

The optical glass of the present invention may have abnormal dispersion. When showing positive abnormal dispersion, the Pg and F of the optical glass are preferably Pg and F satisfying the following formula (1). Pg, F> −0.0004νd + 0.5718...(1) The optical glass that satisfies the formula (1) is suitable as an optical glass for correcting high-order chromatic aberration. In addition, since the composition of the optical glass satisfying the formula (1) generally has a large amount of volatile components, if the variation of the glass characteristics is small, the yield is improved, which is very advantageous in terms of production. Here, Pg and F are partial dispersion ratios, which are indicators of abnormal dispersion. Pg, F uses the refractive index nF in the F line (wavelength 486.13nm), the refractive index nC in the C line (wavelength 656.27nm), and the refractive index ng in the g line (wavelength 435.84nm), as shown in the following formula ( 2) General expression. Pg, F = (ng-nF)/(nF-nC)...(2) When the optical glass of the present invention has abnormal dispersion properties, the lower limit of Pg and F may be, for example, 0.5300 or more, 0.5350 or more, 0.5400 or more, 0.5450 or more, or 0.5500 or more.

As one of the characteristics of the optical glass of the present invention, the values of Pg and F hardly change regardless of the melting time. Specifically, the absolute value of the change of Pg and F (the change per hour) is less than 0.0025. If the absolute value of the change of Pg, F is less than 0.0025, even if the melting time changes for some reason in the manufacturing process, an optical glass having Pg, F within the desired range can be obtained, and the yield can be improved. . The preferable upper limit of the absolute value of the variation of Pg and F (variation per hour) may be less than 0.0020, less than 0.0015, less than 0.0010, or less than 0.0005, for example.

The main dispersion D of the optical glass of the present invention is not particularly limited, and the lower limit may be 0.00400 or more, 0.00450 or more, or 0.00500 or more. The upper limit of D may be 0.01600 or less, and may be 0.01500 or less and 0.01400 or less.

As one of the characteristics of the optical glass of the present invention, the D value hardly changes regardless of the melting time. Specifically, the absolute value of the amount of change in D (the amount of change per hour) is less than 0.00015. If the amount of change in the absolute value of D is less than 0.00015, even if the melting time fluctuates for some reason in the manufacturing process, an optical glass having D in the desired range can be obtained, and the yield can be improved. The preferable upper limit of the absolute value of the change amount of D (the change amount per hour) can be, for example, less than 0.00013, less than 0.00010, less than 0.00009, less than 0.00008, less than 0.00007, less than 0.00006, and less than 0.00005. In addition, the small absolute value of the amount of change in D means that high-dispersion components are not preferentially volatilized. In addition, the main dispersion D has a relationship of D=(nd-1)/νd.

The ng-nF of the optical glass of the present invention is not particularly limited, and the lower limit may be 0.00100 or more, and may be 0.00150 or more and 0.00170 or more. The upper limit of ng-nF may be 0.10000 or less, or 0.09000 or less and 0.08000 or less.

As one of the characteristics of the optical glass of the present invention, the value of ng-nF hardly changes regardless of the melting time. Specifically, the absolute value of the change in ng-nF (the change per hour) is less than 0.00010. If the absolute value of the change in ng-nF is less than 0.00010, even if the melting time is changed for some reason in the manufacturing process, an optical glass having ng-nF within a desired range can be obtained, and the yield can be improved. The preferable upper limit of the absolute value of the change amount of ng-nF (the change amount per hour) can be, for example, less than 0.00008, less than 0.00007, less than 0.00006, or less than 0.00005. In addition, the small absolute value of the change in ng-nF means that high-dispersion components are not preferentially volatilized.

In addition, as one of the characteristics of the optical glass of the present invention, the quality value of the glass hardly changes regardless of the melting time. Specifically, when the melting time of 0 to 90 minutes has elapsed, the absolute value of the mass change is preferably less than 1.5%. The amount of mass change is, for example, less than 1.4%, less than 1.3%, less than 1.2%, less than 1.1%, and less than 1.0%. Here, the melting time of 0 minutes means that the carbonate, nitrate, hydroxide, etc. contained in the batch raw materials (glass powder raw materials, etc.) decompose to produce CO ₂ , NO ₂ , SO ₃ , H ₂ O, etc. The assumed glass quality after the gas.

In addition, the optical glass system of the present invention is such that when it is melted from a glass raw material (powder, etc.) or when the glass raw material is vitrified (glass scrap), the melting causes nd, νd, Pg, F, glass quality, D, ng-nF and other glass with little change in glass properties. That is, the measured values of the various characteristics of the optical glass of the present invention are not easily affected by the state of the raw materials of the glass (in the case of melting from a powder raw material, in the case of melting from glass chips, etc.).

[Optical glass] The optical glass of the present invention includes at least F ^- and Al ³⁺ and F ^- and Al ³⁺ molar ratio (F ^- / Al ³⁺⁾ is 3.0 or more optical glass. From the viewpoint of suppressing the variation of characteristics of the glass melting time due view, F ^- lower limit / Al ^3+, for example, may be 3.1 or more, 3.2 or more, 3.3 or more, 3.4 or more, 3.5 or more, 3.6 or more, 3.7 or more, 3.8 or more , 3.9 or more, 4.0 or more. And, F ^- upper / Al ³⁺ may be, for example, less than 8.0, less than 7.0, less than 6.0.

Hereinafter, the glass components that can be included in the optical glass of the present invention are explained.

As the components of the optical glass of the present invention, Si ⁴⁺ , P ⁵⁺ and B ³⁺ components are components that constitute the glass skeleton and are components that improve the thermal stability of the glass. In addition, it is a component that contributes to low refractive index and low dispersion. The content of each of Si ⁴⁺ , P ^5+, and B ³⁺ components is not particularly limited, and can be any content. The upper limit of each component of Si ⁴⁺ , P ⁵⁺ and B ³⁺ is, for example, 99% or less, 90% or less, 80% or less, 70% or less, 60% or less, 50% or less, 45% or less, 40% or less. , 35% or less, 30% or less, 25% or less, 20% or less, 15% or less, 10% or less, or 5% or less. The lower limit is, for example, 0% or more, 5% or more, 10% or more, or 15% or more. , 20% or more, 25% or more, 30% or more, 35% or more, 40% or more, 45% or more, 50% or more, 60% or more, 70% or more, 80% or 90% or more.

In addition, the total content of Si ⁴⁺ , P ⁵⁺ and B ³⁺ components (Si ⁴⁺ +P ⁵⁺ +B ³⁺ ) is not particularly limited, and can be any value, for example, Si ⁴⁺ +P ^{5 +} + The upper limit of B ³⁺ is 99% or less, 90% or less, 80% or less, 70% or less, 60% or less, 50% or less, 45% or less, 40% or less, 35% or less, 30% or less, 25% Below, 20% or less, 15% or less, 10% or less, 5% or less may also be used. The lower limit is, for example, 0% or more, 5% or more, 10% or more, 15% or more, 20% or more, 25% or more, 30% or more, 35% or more, 40% or more, 45% or more, 50% or more, 60% or more , 70% or more, 80% or more, 90% or more are also possible. In addition, Si ⁴⁺ , P ⁵⁺ , and B ³⁺ may be used alone or in any combination.

In addition, the optical glass of the present invention preferably includes P ⁵⁺ . The P ⁵⁺ component is an essential component for making optical glass into fluorophosphate glass. Since the P ⁵⁺ component is a component that is easily volatilized, the effect is very high if it is possible to suppress the fluctuation of the glass characteristics due to the melting time.

The content of P ^{5+ is} preferably 5 to 50% in terms of cationic %.

When the optical glass of the present invention includes a P ⁵⁺ component, the upper limit of the molar ratio (O ^2- /P ⁵⁺ ) between the O ^2- component and the P ⁵⁺ component is, for example, 4.4 or less, 4.2 or less, or 4.0 or less . The lower limit is 2.8 or more, preferably 3.0 or more.

The optical glass of the present invention may include one or more of Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ and Cs ⁺ components (these components may be referred to as "alkali metal components" hereinafter). Among them, the Li ⁺ component is a component that improves the meltability of the glass and can improve the thermal stability of the glass. In addition, it is a component that lowers the transition temperature of glass. The content of Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ and Cs ⁺ is not particularly limited, and can be set to any content. The upper limit of each content of Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ and Cs ⁺ is, for example, 90% or less, 80% or less, 70% or less, 60% or less, 50% or less, 45% or less, 40% Below, 35% or less, 30% or less, 25% or less, 20% or less, 15% or less, 10% or less, 7.5% or less, 5.0% or less, 4.0% or less, 3.5% or less, 3.0% or less, 2.5% or less, 2.0% or less, 1.5% or less, 1.0%, 0.5% or less. The lower limit is, for example, 0%, 0% or more, 0.1% or more, 0.5% or more, 1.0% or more, 1.5% or more, 2.0% or more, 2.5% or more, 3.0% or more, 3.5% or more, 4.0% or more, 5.0% or more, 7.5% or more, 10.0% or more, 15.0% or more, 20.0% or more, 25.0% or more, 30.0% or more, 35.0% or more, 40.0% or more, 45.0% or more, 50.0% or more, 60.0% or more, 70.0% or more, 80.0% the above.

The Mg ²⁺ , Ca ²⁺ , Sr ²⁺ , Ba ²⁺ and Zn ²⁺ components are components that improve the meltability of the glass and can improve the thermal stability of the glass. In addition, the Mg ²⁺ , Ca ²⁺ , Sr ²⁺ , Ba ²⁺ and Zn ²⁺ components are components that lower the glass transition temperature and may have more components than Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ and Cs ⁺ High refractive index. There are no particular restrictions on the respective contents of the Mg ²⁺ , Ca ²⁺ , Sr ²⁺ , Ba ²⁺ and Zn ²⁺ components. The upper limit of each content of Mg ²⁺ , Ca ²⁺ , Sr ²⁺ , Ba ²⁺ and Zn ²⁺ components is 90% or less, 80% or less, 70% or less, 60% or less, 50% or less, 45% or less, 40% or less, 35% or less, 30% or less, 25% or less, 20% or less, 15% or less, 10% or less, 7% or less, 5% or less, 3% or less, 1% or less, or 0.5% or less.

The lower limit of each content of Mg ²⁺ , Ca ²⁺ , Sr ²⁺ , Ba ²⁺ and Zn ²⁺ is, for example, 0% or more, 1% or more, 3% or more, 5% or more, 7% or more, 10% or more, 15% or more, 20% or more, 25% or more, 30% or more, 35% or more, 40% or more, 45% or more, 50% or more, 60% or more, 70% or more, 80% or more, or 90% or more.

There is also nothing special about the total content of each component of Mg ²⁺ , Ca ²⁺ , Sr ²⁺ , Ba ²⁺ and Zn ²⁺ (Mg ²⁺ +Ca ²⁺ +Sr ²⁺ +Ba ²⁺ +Zn ²⁺ ) Limit, the upper limit of Mg ²⁺ +Ca ²⁺ +Sr ²⁺ +Ba ²⁺ +Zn ^{2+ is} , for example, 90% or less, 80% or less, 70% or less, 60% or less, 50% or less, 45% or less, 40 % Or less, 35% or less, 30% or less, 25% or less, 20% or less, 15% or less, 10% or less, 7% or less, 5% or less, 3% or less, 1% or less, or 0.5% or less.

The lower limit of the total content of the Mg ²⁺ , Ca ²⁺ , Sr ²⁺ , Ba ²⁺ and Zn ²⁺ components (Mg ²⁺ +Ca ²⁺ +Sr ²⁺ +Ba ²⁺ +Zn ²⁺ ) is, for example, 0 % Or more, 1% or more, 3% or more, 5% or more, 7% or more, 10% or more, 15% or more, 20% or more, 25% or more, 30% or more, 35% or more, 40% or more, 45% or more , 50% or more, 60% or more, 70% or more, 80% or more, or 90% or more.

La ³⁺ , Gd ³⁺ , Y ³⁺ and Yb ³⁺ components are components with a higher refractive index than Mg ²⁺ , Ca ²⁺ , Sr ²⁺ , and Ba ²⁺ components, and contribute to high refractive index , Low-dispersion components. The thermal stability of glass can be improved by introducing La ³⁺ , Gd ³⁺ , Y ³⁺ and Yb ³⁺ components. The content of each component of La ³⁺ , Gd ³⁺ , Y ³⁺ and Yb ³⁺ is not particularly limited. The upper limit of the content of each component of La ³⁺ , Gd ³⁺ , Y ³⁺ and Yb ^{3+ is} , for example, 90% or less. 80% or less, 70% or less, 60% or less, 50% or less, 45% or less, 40% or less, 35% or less, 30% or less, 25% or less, 20% or less, 15% or less, 10% or less, 7% Below, 5% or less, 3% or less, 1% or less, 0.5% or less may also be used.

The lower limit of each content of La ³⁺ , Gd ³⁺ , Y ³⁺ and Yb ³⁺ components is, for example, 0% or more, 1% or more, 3% or more, 5% or more, 7% or more, 10% or more, or 15% or more. , 20% or more, 25% or more, 30% or more, 35% or more, 40% or more, 45% or more, 50% or more, 60% or more, 70% or more, or 80% or more.

The total content of La ³⁺ , Gd ³⁺ , Y ³⁺ and Yb ³⁺ components (La ³⁺ +Gd ³⁺ +Y ³⁺ +Yb ³⁺ ) is not particularly limited, and La ³⁺ +Gd ³⁺ +Y The upper limit of ³⁺ +Yb ³⁺ is 90% or less, 80% or less, 70% or less, 60% or less, 50% or less, 45% or less, 40% or less, 35% or less, 30% or less, 25% or less, 20 % Or less, 15% or less, 10% or less, 7% or less, 5% or less, 3% or less, 1% or less, or 0.5% or less.

The lower limit of the total content of La ³⁺ +Gd ³⁺ +Y ³⁺ +Yb ³⁺ components (La ³⁺ +Gd ³⁺ +Y ³⁺ +Yb ³⁺ ) is 0% or more, 1% or more, and 3% or more , 5% or more, 7% or more, 10% or more, 15% or more, 20% or more, 25% or more, 30% or more, 35% or more, 40% or more, 45% or more, 50% or more, 60% or more, 70 % Or more, 80% or more, or 90% or more.

Ti ⁴⁺ , Nb ⁵⁺ , Ta ⁵⁺ , W ⁶⁺ and Bi ³⁺ components are components that contribute to high refractive index and high dispersion, and can improve the thermal stability of glass as a network forming component Sex. The contents of Ti ⁴⁺ , Nb ⁵⁺ , Ta ⁵⁺ , W ⁶⁺ and Bi ³⁺ are not particularly limited. The contents of Ti ⁴⁺ , Nb ⁵⁺ , Ta ⁵⁺ , W ⁶⁺ and Bi ³⁺ The upper limit is 90% or less, 80% or less, 70% or less, 60% or less, 50% or less, 45% or less, 40% or less, 35% or less, 30% or less, 25% or less, 20% or less, 15% or less , 10% or less, 7% or less, 5% or less, 3% or less, 1% or less, or 0.5% or less.

The lower limit of each content of Ti ⁴⁺ , Nb ⁵⁺ , Ta ⁵⁺ , W ⁶⁺ and Bi ³⁺ components is 0% or more, 1% or more, 3% or more, 5% or more, 7% or more, 10% or more, 15% or more, 20% or more, 25% or more, 30% or more, 35% or more, 40% or more, 45% or more, 50% or more, 60% or more, 70% or more, or 80% or more.

The total content of each of Ti ⁴⁺ , Nb ⁵⁺ , Ta ⁵⁺ , W ⁶⁺ and Bi ³⁺ components (Ti ⁴⁺ +Nb ⁵⁺ +Ta ⁵⁺ +W ⁶⁺ +Bi ³⁺ ) is not particularly limited. For example, 90% or less, 80% or less, 70% or less, 60% or less, 50% or less, 45% or less, 40% or less, 35% or less, 30% or less, 25% or less, 20% or less, 15% or less, It may be 10% or less, 7% or less, 5% or less, 3% or less, 1% or less, or 0.5% or less.

The lower limit of the total content of the Ti ⁴⁺ , Nb ⁵⁺ , Ta ⁵⁺ , W ⁶⁺ and Bi ³⁺ components (Ti ⁴⁺ +Nb ⁵⁺ +Ta ⁵⁺ +W ⁶⁺ +Bi ³⁺ ) is, for example 0% or more, 1% or more, 3% or more, 5% or more, 7% or more, 10% or more, 15% or more, 20% or more, 25% or more, 30% or more, 35% or more, 40% or more, 45% More than, 50% or more, 60% or more, 70% or more, or 80% or more are also acceptable.

In addition, it is preferable that the optical glass of the present invention includes at least one component selected from the group consisting of Ti ⁴⁺ , Nb ⁵⁺ , and W ⁶⁺ . In the case of optical glass with abnormal dispersion, Pg and F can be increased by adding Ti ⁴⁺ , Nb ⁵⁺ , and W ⁶⁺ . By adding these components, Pg and F higher than the above formula (1) can be obtained, which is preferable.

When the optical glass of the present invention includes a P ⁵⁺ component and a Ti ⁴⁺ component, the molar ratio of the O ^2- component to the P ⁵⁺ component + Ti ⁴⁺ component (O ^2- /(P ⁵⁺ + Ti ⁴⁺ The lower limit of )), from the viewpoint of suppressing volatilization of components in the molten state of glass, 2.8 or more and 3.0 or more are preferable. Moreover, the upper limit is preferably 4.0 or less, 3.8 or less, 3.6 or less, or 3.4 or less, for example.

When the optical glass of the present invention includes a P ⁵⁺ component and a Nb ⁵⁺ component, the molar ratio of the O ^2- component to the P ⁵⁺ component + Nb ⁵⁺ component (O ^2- /(P ⁵⁺ +Nb ⁵⁺ The lower limit of )), from the viewpoint of suppressing volatilization of components in the molten state of glass, 2.8 or more and 3.0 or more are preferable. Moreover, the upper limit is preferably 4.0 or less, 3.8 or less, 3.6 or less, or 3.4 or less, for example.

When the optical glass of the present invention includes a P ⁵⁺ component and a W ⁶⁺ component, the molar ratio of the O ^2- component to the P ⁵⁺ component + W ⁶⁺ component (O ^2- /(P ⁵⁺ + W ⁶⁺ The lower limit of )), from the viewpoint of suppressing volatilization of components in the molten state of glass, 2.8 or more and 3.0 or more are preferable. Moreover, the upper limit is preferably 4.0 or less, 3.8 or less, 3.6 or less, or 3.4 or less, for example. The addition of W ⁶⁺ is effective for Pg and F, but if it is added excessively, the specific gravity may become too large.

As mentioned above, if O ^2- /(P ⁵⁺ + Ti ⁴⁺ ), O ^2- /(P ⁵⁺ +Nb ⁵⁺ ) and O ^2- /(P ⁵⁺ + W ⁶⁺ ) are above the predetermined value , You can suppress the volatilization of the components of the glass in the molten state. This is because cations such as Ti ⁴⁺ , Nb ⁵⁺ , and W ⁶⁺ are thought to easily enter the phosphate network.

Therefore, from the viewpoint of volatilization of the components, it is preferable that the total amount of the O ^2- component with respect to P ⁵⁺ , Ti ⁴⁺ , Nb ⁵⁺ , and W ⁶⁺ is a predetermined ratio or more. Specifically, O ^2- /(P ⁵⁺ +Ti ⁴⁺ +Nb ⁵⁺ +W ⁶⁺ ) is preferably 3.0 or more. When O ^2- /(P ⁵⁺ +Ti ⁴⁺ +Nb ⁵⁺ +W ⁶⁺ ) is 3.0 or more, it is preferable to reduce volatilization from the molten glass. O ^2- /(P ⁵⁺ +Ti ⁴⁺ +Nb ⁵⁺ +W ⁶⁺ ) is more preferably 3.1 or more, still more preferably 3.15 or more, and particularly preferably 3.2 or more. O ^2- /(P ⁵⁺ +Ti ⁴⁺ +Nb ⁵⁺ +W ⁶⁺ ) is preferably in the order of 4.0 or less, 3.8 or less, 3.6 or less, and 3.4 or less.

Zr ⁴⁺ and Al ³⁺ components are components that improve chemical durability, and can improve the thermal stability of glass through introduction. In addition, Al ³⁺ has a function of improving workability. The contents of Zr ⁴⁺ and Al ³⁺ components are not particularly limited. The upper limits of the contents of Zr ⁴⁺ and Al ³⁺ components are, for example, 60% or less, 50% or less, 40% or less, 35% or less, 30% or less, 20% or less, 15% or less, 10% or less, 9% or less, 8% or less, 7%, 6% or less, 5% or less, 4% or less, 3% or less, 2% or less, 1% or less, 0.5% or less It is also possible.

The lower limit of the content of each of the Zr ⁴⁺ and Al ³⁺ components is, for example, 0% or more, 1% or more, 3% or more, 4% or more, 5% or more, 6% or more, 7% or more, 8% or more, or 9% or more , 10% or more, 15% or more, 20% or more, 30% or more, 35% or more, 40% or more, or 50% or more.

In particular, Al ³⁺ is an important component in the optical glass of the present invention. In the above range, the cationic% is preferably 5 to 50%.

The technique for suppressing changes in optical characteristics of the present invention can be applied to all optical glasses, and in particular, optical glasses including P ⁵⁺ , Al ³⁺ , O ^2- , and F ^- , the characteristics of which can be easily confirmed.

In addition, there is no particular restriction on the ratio of P ⁵⁺ to Al ³⁺ , and the effect can be confirmed in optical glass with relatively large P ⁵⁺ or in optical glass with relatively large Al ³⁺ .

According to needs, at least one cation of As, Sb and Sn can be added to the glass. The cations of As, Sb, and Sn have a clarifying effect when the glass is melted, and have an effect of reducing platinum particles in the resulting glass. In addition, the oxidation/reduction state of the glass can be adjusted. The content of the cations of As, Sb, and Sn is not particularly limited. The upper limit of the content of the cations of As, Sb, and Sn is 1% or less, 0.9% or less, 0.8% or less, 0.7% or less, 0.6% or less, 0.5% or less, 0.4% or less, 0.3% or less, 0.2% or less, 0.1% or less, 0.09% or less, 0.08% or less, 0.07% or less, 0.06% or less, 0.05% or less, 0.04% or less, 0.03% or less, 0.02% or less, 0.01% Or less, 0.009% or less, 0.008% or less, 0.007% or less, 0.006% or less, 0.005% or less, 0.004% or less, 0.003% or less, 0.002% or less, or 0.001% or less. In addition, the lower limit of the content of each cation of As, Sb, and Sn is 0% or more, 0.001% or more, 0.002% or more, 0.003% or more, 0.004% or more, 0.005% or more, 0.006% or more, 0.007% or more, 0.008% or more , 0.009% or more, 0.01% or more, 0.02% or more, 0.03% or more, 0.04% or more, 0.05% or more, 0.06% or more, 0.07% or more, 0.08% or more, 0.09% or more, 0.1% or more, 0.2% or more, 0.3 % Or more, 0.4% or more, 0.5% or more, 0.6% or more, 0.7% or more, 0.8% or more, or 0.9% or more.

O ^{2 of the} present invention is used to maintain the thermal stability of glass. The upper limit of the content of O ^2- relative to the total amount of anionic components is 90% or less, 80% or less, 70% or less, 60% or less, 50% or less, 45% or less, 40% or less, 35% or less, 30% Below, 25% or less, 20% or less, 15% or less, 10% or less, 7% or less, 5% or less, 3% or less, 1% or less, or 0.5% or less.

The lower limit of the content of O ^2- relative to the total amount of anionic components is, for example, 0% or more, 1% or more, 3% or more, 5% or more, 7% or more, 10% or more, 15% or more, 20% or more, 25 % Or more, 30% or more, 35% or more, 40% or more, 45% or more, 50% or more, 60% or more, 70% or more, or 80% or more.

In a system where the following halogen ions are not introduced, O ^2- is usually 100%. On the other hand, in the case of fluorophosphate glass, for example, the anion% may be 10 to 80%.

In the optical glass of the present invention may be added ^{F -, Cl -, Br -} , I - halogen ion as an anion component. ^{F -, Cl -, Br -} , I - the upper limit of the content of each of 90% or less, 80%, 70%, 60%, 50%, 45% or less, 40%, 35%, 30 % Or less, 25% or less, 20% or less, 15% or less, 10% or less, 7% or less, 5% or less, 3% or less, 1% or less, or 0.5% or less.

Relative to the total amount of anionic ^{component, F -, Cl -, Br} -, I - the lower limit of the content of each component, for example, 0% or more, more than 1%, 3% or more than 5%, 7%, 10% or more , 15% or more, 20% or more, 25% or more, 30% or more, 35% or more, 40% or more, 45% or more, 50% or more, 60% or more, 70% or more, or 80% or more.

In particular, the F ^- system, which is an important component in the present invention, preferably has an anion% of 20 to 90%.

Among them, F ^- and Cl ^- are introduced to reduce dispersion, and have the function of providing abnormal dispersion of the glass, lowering the glass transition temperature, and improving the chemical durability.

In addition, when there is a problem that radioactive substances are included in the materials depending on the intended use, it is better to suppress the radioisotope content to a certain amount or less or deliberately exclude it (however, contamination as impurities cannot be prevented).

[Method of manufacturing optical glass] The optical glass of the present invention can be obtained by blending, melting, and molding glass raw materials in order to obtain predetermined characteristics, for example. As the glass raw material, for example, phosphate, fluoride, alkali metal compound, or alkaline earth metal compound can be used. Known methods can be used for the glass melting method and molding method.

In addition, the "predetermined temperature" for melting in the present invention refers to a temperature at which glass can be completely melted. The specific predetermined temperature is (A) 950°C or (B) glass liquidus temperature (hereinafter sometimes expressed as LT) + 150°C to 400°C melting temperature (LT temperature plus 150°C to LT temperature plus 400° C temperature). Therefore, the predetermined temperature satisfies either of the aforementioned (A) or the aforementioned (B). The specific lower limit of the predetermined temperature is 650°C, 700°C or higher, 750°C or higher, 800°C or higher, 850°C or higher, and 900°C or higher. On the other hand, the upper limit is, for example, 1500°C or lower, 1450°C or lower, 1400°C, 1350°C, 1300°C, 1250°C, 1200°C, 1150°C, 1100°C, 1050°C, 1000°C, 950°C. For example, if the optical glass of the present invention is a fluorophosphate glass, examples of the "predetermined temperature" include 850, 900°C, 950°C, 1000°C, 1050°C, 1100°C, and 1150°C.

In this specification, the LT when determining the predetermined temperature is determined as follows. (1) First, glass chips of a predetermined composition having a volume of 12.5 ml±2.0 ml are put into a platinum crucible and kept at a temperature that can be sufficiently melted in an N ₂ gas environment for 2 hours. The glass kept for 2 hours was observed, and it was confirmed that no crystals had precipitated. (2) The temperature was lowered every 50°C, the same experiment was performed, and the lowest temperature at which crystal precipitation was not confirmed was taken as LT. For example, if 800°C is “crystallized”, 850°C is “no crystallization”, and 900°C is “no crystallization”, then 850°C is LT. The presence or absence of precipitation of crystals is determined by confirming the presence or absence of crystals at the interface between the glass and the platinum crucible and the inside of the glass with an optical microscope. When it is confirmed that there are crystals with a crystal size of 10 μm or more, it is judged as "crystals". In addition, for example, a platinum crucible having a bottom inner diameter of 30 mm to 60 mm may be used. The shape of the platinum crucible can be a cylinder, a truncated cone, etc. It is better to cool the platinum crucible for the glass melt system after melting the glass chips, without taking out the sample from the crucible, but to observe with an optical microscope. Therefore, the thickness of the glass sample is preferably 1 to 10 mm at room temperature, and more preferably 2 to 5 mm.

The gas environment when the optical glass of the present invention is melted can be appropriately changed according to the material of the optical glass. For example, glass with Si ⁴⁺ as the main component, or glass with B ³⁺ and La ³⁺ as the main component, or glass with B ³⁺ , La ³⁺ , and Nb ⁵⁺ as the main component can be in the atmosphere Under non-oxidizing gas environment, in reducing gas environment, etc. Furthermore, in the case of fluorophosphate glass, it can be melted in a non-oxidizing gas atmosphere (specifically, N ₂ gas atmosphere, Ar gas atmosphere, etc.). [Example]

Hereinafter, the present invention will be explained in detail using examples, but the present invention is not limited to these examples.

(Measurement of optical glass characteristics) Use optical glass grade high-purity oxides, hydroxides, carbonates, nitrates, chlorides, fluorides, sulfates and other raw materials to obtain the glass with the composition of each embodiment and comparative example in Table 1. The raw materials are mixed and used as blending raw materials. Next, put each blended raw material into each platinum crucible, heat to a predetermined temperature as described above, in a nitrogen atmosphere, from the beginning to melting for 2 hours or 4 hours, stir and homogenize, then stand and proceed. After clarification, pour into the mold. After the glass is cured, it is then moved to an electric furnace heated to near the annealing point of the glass and annealed to room temperature. In this way, glass blocks including the respective examples and comparative examples were produced. A test piece required for the measurement was cut out from each obtained glass block, and subjected to grinding processing for characteristic evaluation. Table 4 shows the change results of each characteristic.

(1) Measurement of nd, ng, nF, nC and Abbe number νd Regarding the glass obtained by cooling at a cooling rate of -30°C/hour, the refractive index nd, ng, nF, nC, and Abbe number νd were measured by the refractive index measurement method of Japanese Industrial Standards JIS B7071.

(2) Measurement of partial dispersion ratio Pg, F Calculate the partial dispersion ratios Pg, F from the nd, ng, nF, and nC obtained in (1) above.

(Measurement of glass quality change) As a glass batch, prepare a batch of glass raw materials so that the output A is 150 to 200 grams, put the batch raw materials in a platinum crucible, cover with a platinum lid, and measure the batch Quality of raw materials, platinum crucible and lid. Then, cover the platinum crucible with the batch of raw materials, put the batch of raw materials into the glass melting furnace with each crucible, and place them at 900°C, 950°C, 1050°C or 1100°C for 1.5 hours (90 minutes) ) Heating to melt glass. After 1.5 hours (90 minutes), the mass of the contents (molten glass) of each platinum crucible was measured with the platinum lid covered. In addition, the total mass of the platinum crucible, platinum lid, and batch raw materials before glass melting is B, the mass of batch raw materials is C, the total mass of platinum crucible, platinum lid, and molten glass after glass melting For D, the quality of the glass component lost due to volatilization from the molten glass in the crucible during the melting process is {B-(CA)}-D. CA is the mass of gas produced by thermal decomposition of batch materials due to heating. This gas is not a glass component, but CO ₂ , NO ₂ , SO ₃ , H ₂ O, etc. generated during thermal decomposition of carbonates, nitrates, sulfates, hydroxides, etc. used as batch materials. The amount of these gases produced can be calculated by known methods. In this specification, B-(CA) is the glass quality with a melting time of 0 hours. The reduction in volatilization of the glass components before and after melting is the value of the mass of the glass components ({B-(CA)}-D) lost due to volatilization from the molten glass in the crucible during the melting process divided by the output of the glass, that is, It is calculated as the percentage of [{B-(CA)}-D]/A. The results of the glass quality change are shown in Table 3.

Table 1 (indicated by cation% and anion %) and Table 2 (indicated by element ratio) show the compositions of the glasses used in the examples and comparative examples. Table 3 shows the glass characteristics as a benchmark for each glass. In addition, in Table 3, the values of nd, νd, Pg, F, D, and ng-nF are the values after glass melting for 1.5 hours.

In addition, LT in Table 3 is a value measured by the method described in the specification. In addition, all the glasses used for the measurement are 50g, and the glass volume is within the range of 12.5ml±2.0ml.

[Table 1]

[Table 2]

[table 3]

[Table 4]

It can be seen from the examples and comparative examples that by setting Al ³⁺ /F ^- within a predetermined range, even if the melting time is increased from two hours to 4 hours (with respect to the glass quality, it is 0 to 90 minutes), nd, νd, The glass characteristics of Pg, F, glass quality, D, ng-nF, etc. change very little.

The optical glass of the present invention can be used as a material for optical elements.

no.

no.

Claims (25)

An optical glass comprising at least F ^- and Al ³⁺ and F ^- / Al ³⁺ in 3.0 above, when molten at a predetermined temperature, the amount of change in the absolute value of nd (the amount of change per hour) is less than 0.00050. For the optical glass described in item 1 of the scope of patent application, the Pg and F of the aforementioned optical glass satisfy the following formula (1): Pg, F> −0.0004νd+0.5718...(1). The optical glass described in item 1 or item 2 of the scope of patent application includes at least one component selected from the group consisting of Ti ⁴⁺ , Nb ⁵⁺ and W ⁶⁺ . The optical glass described in any one of items 1 to 3 in the scope of the patent application, wherein O ^2- /(P ⁵⁺ +Ti ⁴⁺ +Nb ⁵⁺ +W ⁶⁺ ) is 3.0 or more. An optical glass comprising at least F ^- and Al ³⁺ and F ^- / Al ³⁺ in 3.0 above, when molten at a predetermined temperature, the absolute value of the change amount νd (change amount per hour) is less than 1.50. For the optical glass described in item 5 of the scope of patent application, the Pg and F of the aforementioned optical glass satisfy the following formula (1): Pg, F> −0.0004νd+0.5718...(1). The optical glass described in item 5 or item 6 of the scope of patent application includes at least one component selected from the group consisting of Ti ⁴⁺ , Nb ⁵⁺ and W ⁶⁺ . For the optical glass described in any one of items 5 to 7 of the scope of patent application, wherein O ^2- /(P ⁵⁺ +Ti ⁴⁺ +Nb ⁵⁺ +W ⁶⁺ ) is 3.0 or more. An optical glass comprising at least F ^- and Al ³⁺ and F ^- / Al ³⁺ in 3.0 above, when molten at a predetermined temperature, Pg, F of the absolute value of the change amount (change amount per hour) is less than 0.0025 . For the optical glass described in item 9 of the scope of patent application, the Pg and F of the aforementioned optical glass satisfy the following formula (1): Pg, F> −0.0004νd+0.5718...(1). The optical glass described in item 9 or item 10 of the scope of patent application includes at least one component selected from the group consisting of Ti ⁴⁺ , Nb ⁵⁺ and W ⁶⁺ . For the optical glass described in any one of items 9 to 11 in the scope of the patent application, O ^2- /(P ⁵⁺ +Ti ⁴⁺ +Nb ⁵⁺ +W ⁶⁺ ) is 3.0 or more. An optical glass comprising at least F ^- and Al ³⁺ and F ^- / Al ³⁺ in 3.0 above, when molten at a predetermined temperature, mass changes from zero to 90 minutes is less than 1.5%. For the optical glass described in item 13 of the scope of patent application, the Pg and F of the aforementioned optical glass satisfy the following formula (1): Pg, F> −0.0004νd+0.5718...(1). The optical glass described in item 13 or item 14 of the scope of the patent application includes at least one component selected from the group consisting of Ti ⁴⁺ , Nb ⁵⁺ and W ⁶⁺ . For the optical glass described in any one of items 13 to 15 in the scope of the patent application, O ^2- /(P ⁵⁺ +Ti ⁴⁺ +Nb ⁵⁺ +W ⁶⁺ ) is 3.0 or more. An optical glass comprising at least F ^- and Al ³⁺ and F ^- / Al ³⁺ in 3.0 above, when molten at a predetermined temperature, D (nF-nC) of the amount of change (amount of change per hour) absolute The value is less than 0.00015. For the optical glass described in item 17 of the scope of patent application, the Pg and F of the aforementioned optical glass satisfy the following formula (1): Pg, F> −0.0004νd+0.5718 (1). The optical glass described in item 17 or item 18 of the scope of patent application includes at least one component selected from the group consisting of Ti ⁴⁺ , Nb ⁵⁺ and W ⁶⁺ . The optical glass described in any one of items 17 to 19 in the scope of the patent application, wherein O ^2- /(P ⁵⁺ +Ti ⁴⁺ +Nb ⁵⁺ +W ⁶⁺ ) is 3.0 or more. An optical glass comprising at least F ^- and Al ³⁺ and F ^- / Al ³⁺ in 3.0 above, when molten at a predetermined temperature, the absolute value of the change amount ng-nF (change amount per hour) is less than 0.00010 . For the optical glass described in item 21 of the scope of patent application, the Pg and F of the aforementioned optical glass satisfy the following formula (1): Pg, F> −0.0004νd + 0.5718...(1). The optical glass described in item 21 or item 22 of the scope of patent application includes at least one component selected from the group consisting of Ti ⁴⁺ , Nb ⁵⁺ and W ⁶⁺ . For the optical glass described in any one of items 21 to 23 in the scope of the patent application, O ^2- /(P ⁵⁺ +Ti ⁴⁺ +Nb ⁵⁺ +W ⁶⁺ ) is 3.0 or more. An optical element, including the optical glass described in any one of items 1 to 24 of the scope of patent application.