TWI817938B - Optical glass, preform structures and optical components - Google Patents

Abstract

The present invention provides optical glass having a refractive index (n _d ) of 1.63 or more, an Abbe number (ν _d ) of 33 to 55, and a small average linear thermal expansion coefficient, as well as a preform structure using the optical glass and Optical components. Optical glass contains, in mass %, B ₂ O ₃ components from 20.0% to 45.0%, ZnO components from 35.0% to 66.0%, SiO ₂ components from 0% to less than 15.0%, Al ₂ O ₃ components from 0% to 10.0%, Rn ₂ O composition is 0% to 3.0% (in the formula, Rn is one or more species selected from the group consisting of Li, Na, and K), and has a mass product (Rn ₂ O×SiO ₂ ) of 0 to 10.0, refraction The rate (n _d ) is 1.63 to 1.77, and the Abbe number (ν _d ) is 33 to 55.

Description

Optical glass, preformed body materials and optical components

The present invention relates to optical glass, preformed body materials, and optical elements.

In recent years, digitization and high-definition of equipment using optical systems have been rapidly developed. In the field of various optical equipment such as digital cameras and video cameras, image reproduction (projection) equipment such as projectors and projection televisions, for There is an increasing demand to reduce the number of optical components such as lenses and lenses used in optical systems to reduce the weight and size of the entire optical system.

Among the optical glasses used to make optical elements, it is particularly desirable to reduce the weight and size of the entire optical system or to correct chromatic aberrations. It has a refractive index (n _d ) of 1.63 or more and 33 or more and 55 or less. The demand for low-refractive-index dispersion glass among Bay numbers (ν _d ) has become very high.

As such medium refractive index low dispersion glass, glass compositions represented by Patent Documents 1 to 3 are known. However, these glass compositions contain a large amount of alkali metal components (Li ₂ O components, Na ₂ O components, K ₂ O components). When moisture in the atmosphere reacts with alkali metal ions, it will cause the glass material to The cause of discoloration itself may also be the cause of contamination of electronic components near alkali metal ions, resulting in degradation of device performance or defects or malfunctions.

In addition, compositions with a small content of alkali metal components have poor melting properties of the raw materials, which may cause problems in productivity or quality during melting. For example, when the glass is melted, residues from the melting of the raw materials may occur.

[Prior technical literature]

[Patent Document]

Patent Document 1: Japanese Patent Application Publication No. 1996-059281.

Patent Document 2: Japanese Patent Application Publication No. 2007-008761.

Patent Document 3: Japanese Patent Application Publication No. 2001-079684.

The present invention was developed in view of the above-mentioned problems. An object of the present invention is to obtain an optical glass having optical constants within the above-mentioned specified range, a small average linear thermal expansion coefficient, a small content of alkali metal components, and excellent meltability.

In order to solve the above-mentioned problems, the present inventors concentrated on accumulating the results of experimental studies and found that a glass that solves the above-mentioned problems can be obtained by having a specific composition, and completed the present invention. Specifically, the present invention provides the following.

(1) An optical glass, characterized in that: in terms of mass %, the B ₂ O ₃ component is 20.0% to 45.0%, the ZnO component is 35.0% to 66.0%, the SiO ₂ component is 0% to less than 15.0%, and the Al _{The 2} O ₃ component is 0% to 10.0%, the Rn ₂ O component is 0% to 3.0% (in the formula, Rn is one or more selected from the group consisting of Li, Na, and K), and the mass product (Rn ₂ O×SiO ₂ ) is 0 to 10.0, the refractive index (nd) is 1.63 to 1.77, and the Abbe number (νd) is 33 to 55.

(2) The optical glass as described in (1), wherein in terms of mass %, the TiO ₂ component is 0% to 10.0%, the Li ₂ O component is 0% to 3.0%, and the Na ₂ O component is 0% to 3.0% , K ₂ O composition is 0% to 3.0%.

(3) The optical glass as described in (1) or (2), wherein in terms of mass %, the La ₂ O ₃ component is 0% to 25.0%, the Y ₂ O ₃ component is 0% to 15.0%, and the Gd ₂ O _{The 3} component is 0% to 15.0%, the Lu ₂ O ₃ component is 0% to 1.0%, the Yb ₂ O ₃ component is 0% to 1.0%, the ZrO ₂ component is 0% to 5.0%, and the Nb ₂ O ₅ component is 0 % to 5.0%, Ta ₂ O ₅ component is 0% to 5.0%, WO ₃ component is 0% to 5.0%, MgO component is 0% to 10.0%, CaO component is 0% to 10.0%, SrO component is 0% to 10.0%, BaO composition is 0% to 10.0%, GeO ₂ composition is 0% to 5.0%, Ga ₂ O ₃ composition is 0% to 5.0%, P ₂ O ₅ composition is 0% to 10.0%, Bi ₂ O ₃ component is 0% to 5.0%, TeO ₂ component is 0% to 5.0%, SnO ₂ component is 0% to 3.0%, Sb ₂ O ₃ component is 0% to 1.0%, CeO ₂ component is 0% to 1.0% , the Fe ₂ O ₃ component is 0% to 0.5%, and the Ag ₂ O component is 0% to 3.0%; F is a fluoride that partially or completely replaces one or more of the oxides of each of the above metal elements. The content is 0 mass% to 15.0 mass%.

(4) The optical glass according to any one of (1) to (3), wherein the RO component (in the formula, R is one or more selected from the group consisting of Mg, Ca, Sr, and Ba) The mass sum is 0% to 10.0%; the mass sum of the Ln ₂ O ₃ component (in the formula, Ln is one or more selected from the group consisting of La, Gd, Y, and Lu) is 0% to 25.0%.

(5) The optical glass according to any one of (1) to (4), wherein the liquidus temperature in the temperature gradient furnace is 1150°C or lower.

(6) The optical glass according to any one of (1) to (5), wherein the average linear thermal expansion coefficient α at 100°C to 300°C is 100 (10 ^-7 °C ^-1 ) or less.

(7) The optical glass as described in any one of (1) to (6), wherein the mass and B ₂ O ₃ +ZnO are less than 99.5%.

(8) The optical glass according to any one of (1) to (7), wherein the mass ratio B ₂ O ₃ /(SiO ₂ +Al ₂ O ₃ ) is 1.0 or more.

(9) The optical glass according to any one of (1) to (8), wherein the mass ratio B ₂ O ₃ /ZnO is 1.5 or less.

(10) A preform structure made of the optical glass according to any one of (1) to (9).

(11) An optical element made of the optical glass according to any one of (1) to (9).

(12) An optical machine including the optical element according to (11).

According to the present invention, it is possible to obtain an optical glass that has an optical constant within a prescribed range, a small average linear thermal expansion coefficient, a small content of alkali metal components, and excellent meltability.

Hereinafter, embodiments of the optical glass of the present invention will be described in detail. However, the present invention is not limited to the following embodiments and can be implemented with appropriate changes within the scope of the purpose of the present invention. In addition, descriptions of portions whose descriptions are repeated may be appropriately omitted, but this does not limit the gist of the invention.

[Glass composition]

The composition range of each component constituting the optical glass of the present invention is as follows. In this specification, unless otherwise specified, the content of each component is expressed in mass % relative to the total mass of the glass converted into oxides. Here, the "oxide-converted composition" means that assuming that the oxides, complex salts, metal fluorides, etc. used as the raw materials for the glass constituents of the present invention are all decomposed into oxides during melting, the resulting The total mass of oxides is set to 100% by mass to represent the composition of various components contained in the glass.

The B ₂ O ₃ component is an essential component that has the effect of improving meltability and improving devitrification resistance.

Therefore, the lower limit of the content of the B ₂ O ₃ component is preferably 20.0%, more preferably 21.0%, more preferably 22.0%, still more preferably 23.0%, still more preferably 24.0%, and most preferably 25.0 %.

On the other hand, by setting the content of the B ₂ O ₃ component to 45.0%, deterioration of chemical durability can be suppressed. Therefore, the upper limit of the content of the B ₂ O ₃ component is preferably 45.0%, more preferably 43.0%, more preferably 41.0%, still more preferably 39.0%, and most preferably 38.0%.

As the B ₂ O ₃ component, H ₃ BO ₃ , Na ₂ B ₄ O ₇ , Na ₂ B ₄ O ₇ ‧10H ₂ O, BPO ₄ , etc. can be used as raw materials.

ZnO is an essential component for obtaining desired optical constants while suppressing deterioration in transmittance and increase in average linear thermal expansion coefficient. Therefore, the lower limit of the content of the ZnO component is preferably 35.0%, more preferably 38.0%, more preferably 41.0%, still more preferably 43.0%, still more preferably 45.0%, and most preferably 46.0%.

On the other hand, by setting the content of the ZnO component to 66.0% or less, it is possible to suppress a decrease in devitrification resistance caused by excessive content. Therefore, the upper limit of the content of the ZnO component is preferably 66.0%, more preferably 64.0%, more preferably 62.0%, and even more preferably 60.0%.

As a ZnO component, ZnO, ZnF ₂ , etc. can be used as raw materials.

The SiO ₂ component is any component that can improve devitrification resistance or chemical durability when its content is greater than 0%. Therefore, the lower limit of the content of the SiO ₂ component is preferably greater than 0%, preferably 0.5%, more preferably 1.0%, and most preferably 1.5%.

On the other hand, by setting the content of the SiO ₂ component to less than 15.0%, a larger refractive index can be easily obtained, and deterioration of meltability or excessive increase in viscosity can be suppressed. Therefore, the upper limit of the content of the SiO ₂ component is preferably less than 15.0%, preferably 10.0%, more preferably 8.0%, still more preferably 6.0%, still more preferably 4.5%, and most preferably low at 3.0%.

As the SiO ₂ component, SiO ₂ , K ₂ SiF ₆ , Na ₂ SiF ₆ , etc. can be used as raw materials.

The Al ₂ O ₃ component is any component that can improve chemical durability when its content is greater than 0%. Therefore, the lower limit of the content of the Al ₂ O ₃ component is preferably greater than 0%, more preferably greater than 0.1%, and more preferably 0.5%.

On the other hand, by setting the content of the Al ₂ O ₃ component to 10.0% or less, deterioration of devitrification resistance, phase separation, and reduction in refractive index caused by excess content can be suppressed. Therefore, the upper limit of the content of the Al ₂ O ₃ component is preferably 10.0%, preferably 8.0%, more preferably 6.0%, still more preferably 4.0%, still more preferably less than 2.5%, and the best It's 1.0%.

As the Al ₂ O ₃ component, Al ₂ O ₃ , Al(OH) ₃ , AlF ₃ , Al(PO ₃ ) ₃ , etc. can be used as raw materials.

The total content (mass sum) of the Rn ₂ O component (in the formula, Rn is one or more species selected from the group consisting of Li, Na, and K) is preferably 3.0% or less. Thereby, it is possible to suppress deterioration of devitrification resistance or chemical durability due to excessive content, and to suppress alkali contamination of electronic equipment. Therefore, the upper limit of the quality sum is preferably 3.0%, more preferably 2.0%, more preferably 1.0%, and most preferably 0.5%.

On the other hand, by setting the mass sum to be greater than 0%, meltability or formability can be improved. Therefore, the lower limit of the mass sum of the Rn ₂ O component is preferably greater than 0%, more preferably greater than 0.1%, and more preferably 0.3%.

In particular, from the viewpoint of preventing corrosion of electronic parts or electronic equipment due to elution of alkali metal components, the Rn ₂ O component does not need to be contained.

When the mass product (Rn ₂ O × SiO ₂ ) is 10.0 or less, deterioration of the meltability of the glass raw material can be suppressed, while deterioration of chemical durability and alkali contamination of electronic equipment can be suppressed.

Therefore, the upper limit of the mass product (Rn ₂ O × SiO ₂ ) is preferably 10.0 or less, more preferably 8.0 or less, more preferably less than 6.0, still more preferably 5.0, still more preferably 4.0, and still more preferably Better is 3.0, still better is 2.0, still better is 1.0, still better is 0.5, and the best is 0.1.

Here, Rn in the formula is one or more types selected from the group consisting of Li, Na, and K.

The TiO ₂ component is any component that can increase the refractive index of glass and inhibit exposure (color change caused by ultraviolet rays) when the content is greater than 0%.

Therefore, the lower limit of the content of the TiO ₂ component is preferably greater than 0%, preferably 0.1%, more preferably 0.2%, further preferably 0.3%, still more preferably 0.4%, and still more preferably 0.5%, the best is 0.6%.

On the other hand, by setting the content of the TiO ₂ component to 10.0% or less, devitrification caused by containing an excess TiO ₂ component can be reduced, and the penetration of visible light (especially wavelengths below 500 nm) in the glass can be suppressed. Rate is low. Therefore, the upper limit of the content of the TiO ₂ component is preferably 10.0%, more preferably 8.0%, more preferably 6.0%, still more preferably 4.0%, still more preferably 2.0%, and most preferably 1.0%.

The TiO ₂ component can be contained in the glass using, for example, TiO ₂ or the like as a raw material.

The Li ₂ O component is any component that can improve low-temperature meltability when its content exceeds 0%.

On the other hand, by setting the content of the Li ₂ O component to 3.0% or less, deterioration in chemical durability caused by excessive inclusion of the Li ₂ O component can be suppressed. Therefore, the upper limit of the Li ₂ O component content is preferably 3.0%, more preferably 2.0%, and most preferably 1.0%.

As the Li ₂ O component, Li ₂ CO ₃ , LiNO ₃ , etc. can be used as raw materials.

The Na ₂ O component is any component that can improve low-temperature meltability when the content exceeds 0%.

On the other hand, by setting the content of the Na ₂ O component to 3.0% or less, it is possible to suppress deterioration in chemical durability caused by excessive inclusion of the Na ₂ O component. Therefore, the upper limit of the content of the Na ₂ O component is preferably 3.0%, more preferably 2.5%, more preferably 2.0%, still more preferably 1.5%, still more preferably 1.0%, still more preferably 0.8%, the best is 0.6%.

On the other hand, by setting the content of the Na ₂ O component to more than 0%, meltability or formability can be improved. Therefore, the lower limit of the content of the Na ₂ O component is preferably greater than 0%, more preferably greater than 0.1%, more preferably 0.3%, and most preferably 0.5%.

As the Na ₂ O component, Na ₂ CO ₃ , NaNO ₃ , NaF, Na ₂ SiF ₆ , etc. can be used as raw materials.

The K ₂ O component is any component that can improve low-temperature meltability when its content exceeds 0%.

On the other hand, by setting the content of the K ₂ O component to 3.0% or less, deterioration in chemical durability caused by excessive K ₂ O component content can be suppressed. Therefore, the upper limit of the content of the K ₂ O component is preferably 3.0%, more preferably 2.0%, more preferably 1.0%, still more preferably 0.8%, still more preferably 0.6%, and most preferably 0.5% .

As a K ₂ O component, K ₂ CO ₃ , KNO ₃ , KF, KHF ₂ , K ₂ SiF ₆ , etc. can be used as raw materials.

The La ₂ O ₃ component is any component that can increase the refractive index of the glass and increase the Abbe number of the glass when the content is greater than 0%. Therefore, the lower limit of the content of the La ₂ O ₃ component is preferably greater than 0%, preferably 5.0%, and more preferably 10.0%.

On the other hand, by setting the content of the La ₂ O ₃ component to 25.0% or less, it is possible to reduce devitrification by improving glass stability. Therefore, the upper limit of the content of the La ₂ O ₃ component is preferably 25.0%, more preferably 23.0%, more preferably 21.0%, and even more preferably 20.0%.

As the La ₂ O ₃ component, La ₂ O ₃ , La(NO ₃ ) ₃ ‧XH ₂ O (X is an arbitrary integer), etc. can be used as raw materials.

The Y ₂ O ₃ component is any component that, when its content is greater than 0%, can reduce the material cost of glass while maintaining a high refractive index and high Abbe number, and can reduce the specific gravity of glass more than other rare earth components. .

On the other hand, by setting the content of the Y ₂ O ₃ component to 15.0% or less, the devitrification resistance of the glass can be improved. Therefore, the lower limit of the content of the Y ₂ O ₃ component is preferably 15.0%, more preferably 10.0%, more preferably 8.0%, still more preferably 6.0%, still more preferably 4.0%, and most preferably 3.0 %.

As the Y ₂ O ₃ component, Y ₂ O ₃ , YF ₃ , etc. can be used as raw materials.

The Gd ₂ O ₃ component is any component that can increase the refractive index of glass and increase the Abbe number when the content exceeds 0%.

On the other hand, by setting the content of the Gd ₂ O ₃ component, which is also expensive among rare earth elements, to 15.0% or less, an increase in specific gravity can be suppressed and the material cost of the glass can be reduced, so that cheaper optics can be produced. Glass. Therefore, the upper limit of the content of the Gd ₂ O ₃ component is preferably 15.0%, more preferably 10.0%, more preferably 8.0%, still more preferably 5.0%, still more preferably 3.0%.

Gd ₂ O ₃ component, Gd ₂ O ₃ , GdF ₃ , etc. can be used as raw materials.

The Lu ₂ O ₃ component is any component that can increase the refractive index of glass and increase the Abbe number when the content is greater than 0%.

On the other hand, by setting the content of the Lu ₂ O ₃ component to 1.0% or less, the material cost of the glass can be reduced, so that cheaper optical glass can be produced. In addition, the devitrification resistance of the glass can be improved thereby. Therefore, the upper limit of the Lu ₂ O ₃ component content is preferably 1.0%, more preferably 0.5%, more preferably 0.3%, and most preferably 0.1%. From the viewpoint of reducing material costs, the Lu ₂ O ₃ component may not be included.

Lu ₂ O ₃ component, Lu ₂ O ₃ , etc. can be used as raw materials.

The Yb ₂ O ₃ component is any component that can increase the refractive index of glass and increase the Abbe number when the content exceeds 0%.

On the other hand, by setting the content of the Yb ₂ O ₃ component to 1.0% or less, the material cost of the glass can be reduced, so that cheaper optical glass can be produced. In addition, the devitrification resistance of the glass can be improved thereby. Therefore, the upper limit of the content of the Yb ₂ O ₃ component is preferably 1.0%, more preferably 0.5%, more preferably less than 0.3%, and most preferably 0.1%. From the viewpoint of reducing material costs, the Yb ₂ O ₃ component may not be included.

Yb ₂ O ₃ component, Yb ₂ O ₃ , etc. can be used as raw materials.

The ZrO ₂ component is any component that can increase the refractive index and Abbe number of the glass and improve the devitrification resistance when the content is greater than 0%.

On the other hand, by setting the content of the ZrO ₂ component to 5.0% or less, devitrification caused by excessive ZrO ₂ component content can be reduced. Therefore, the upper limit of the content of the ZrO ₂ component is preferably 5.0%, preferably 3.0%, more preferably less than 2.5%, still more preferably 1.0%, still more preferably 0.5%, still more preferably is 0.3%, and the best is 0.1%.

As a ZrO ₂ component, ZrO ₂ , ZrF ₄ , etc. can be used as raw materials.

The Nb ₂ O ₅ component is any component that can increase the refractive index of glass when its content exceeds 0%.

On the other hand, by setting the content of the Nb ₂ O ₅ component to 5.0% or less, devitrification caused by containing excess Nb ₂ O ₅ component can be reduced, and the sensitivity of the glass to visible light (especially wavelengths of 500 nm or less) can be suppressed. ) has low penetration rate.

Therefore, the upper limit of the content of the Nb ₂ O ₅ component is preferably 5.0%, more preferably 3.0%, more preferably 2.0%, still more preferably 1.0%, still more preferably 0.5%, still more preferably is 0.3%, and the best is 0.1%.

Nb ₂ O ₅ component, Nb ₂ O ₅ , etc. can be used as raw materials.

The Ta ₂ O ₅ component is any component that can increase the refractive index of the glass and improve the devitrification resistance when the content exceeds 0%.

On the other hand, by setting the expensive Ta ₂ O ₅ component to 5.0% or less, the material cost of the glass can be reduced, and therefore more affordable optical glass can be produced. Therefore, the upper limit of the content of the Ta ₂ O ₅ component is preferably 5.0%, more preferably 3.0%, more preferably 1.0%, and still more preferably 0.1%. From the viewpoint of reducing material costs, the Ta ₂ O ₅ component may not be included.

Ta ₂ O ₅ component, Ta ₂ O ₅ , etc. can be used as raw materials.

The WO ₃ component is any component that can increase the refractive index of the glass and improve the devitrification resistance when the content is greater than 0%.

On the other hand, by setting the content of the WO ₃ component to 5.0% or less, the coloring of the glass caused by the WO ₃ component can be reduced and the visible light transmittance can be improved. Therefore, the upper limit of the content of the WO ₃ component is preferably 5.0%, more preferably 3.0%, more preferably 2.0%, still more preferably 1.0%, still more preferably 0.5%, still more preferably 0.3 %, and even better is 0.1%.

As the WO ₃ component, WO ₃ and the like can be used as raw materials.

The MgO component is any component that can improve low-temperature meltability when its content is greater than 0%.

On the other hand, by setting the content of the MgO component to 10.0% or less, it is possible to suppress deterioration in chemical durability or reduction in devitrification resistance caused by excessive MgO component content. Therefore, the upper limit of the content of the MgO component is preferably 10.0%, more preferably 5.0%, more preferably 3.0%, still more preferably 1.0%, still more preferably 0.5%, still more preferably 0.3% , the best is 0.1%.

For the MgO component, MgCO ₃ , MgF ₂ , etc. can be used as raw materials.

The CaO component is any component that can improve low-temperature meltability when the content is greater than 0%.

On the other hand, by setting the content of the CaO component to 10.0% or less, it is possible to suppress deterioration in chemical durability or reduction in devitrification resistance due to excessive inclusion of the CaO component. Therefore, the upper limit of the content of the CaO component is preferably 10.0%, more preferably 5.0%, more preferably 3.0%, still more preferably 1.0%, still more preferably 0.5%, still more preferably 0.3% , the best is 0.1%.

As a CaO component, CaCO ₃ and CaF ₂ can be used as raw materials.

The SrO component is any component that can improve low-temperature meltability when its content is greater than 0%.

On the other hand, by setting the content of the SrO component to 10.0% or less, deterioration of chemical durability or low devitrification resistance caused by excessive SrO component content can be suppressed. Down. Therefore, the upper limit of the content of the SrO component is preferably 10.0%, more preferably 5.0%, more preferably 3.0%, still more preferably 1.0%, still more preferably 0.5%, still more preferably 0.3% , the best is 0.1%.

As the SrO component, Sr(NO ₃ ) ₂ and SrF ₂ can be used as raw materials.

The BaO component is any component that can improve low-temperature meltability when the content is greater than 0%.

On the other hand, by setting the content of the BaO component to 10.0% or less, it is possible to suppress deterioration in chemical durability or reduction in devitrification resistance caused by excessive BaO component content. Therefore, the upper limit of the content of the BaO component is preferably 10.0%, more preferably 5.0%, more preferably 3.0%, still more preferably 1.0%, still more preferably 0.5%, still more preferably 0.3% , the best is 0.1%.

As the BaO component, BaCO ₃ , Ba(NO ₃ ) ₂ , BaF ₂ , etc. can be used as raw materials.

The GeO ₂ component is any component that can increase the refractive index of the glass and improve the devitrification resistance when the content is greater than 0%.

However, since the raw material of GeO ₂ is expensive, if its content is high, the production cost will be high. Therefore, the upper limit of the content of the GeO ₂ component is preferably 5.0%, more preferably 3.0%, more preferably 1.0%, and still more preferably 0.1%. From the viewpoint of reducing material costs, the GeO ₂ component may not be included.

GeO ₂ component, GeO ₂ etc. can be used as raw materials.

The Ga ₂ O ₃ component is any component that can increase the refractive index of the glass and improve the devitrification resistance when the content exceeds 0%.

However, since the raw material of Ga ₂ O ₃ is expensive, if its content is high, the production cost will be high. Therefore, the upper limit of the content of the Ga ₂ O ₃ component is preferably 5.0%, more preferably 3.0%, more preferably 1.0%, and still more preferably 0.1%. From the viewpoint of reducing material costs, the Ga ₂ O ₃ component may not be included.

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

When the content of the P ₂ O ₅ component exceeds 0%, it is any component that can lower the liquidus temperature of the glass and improve the devitrification resistance.

On the other hand, by setting the content of the P ₂ O ₅ component to 10.0% or less, it is possible to suppress a decrease in the chemical durability of the glass, especially a decrease in the water resistance. Therefore, the upper limit of the content of the P ₂ O ₅ component is preferably 10.0%, more preferably 8.0%, more preferably 6.0%, still more preferably 4.0%, still more preferably 2.0%, still more preferably 1.0%, the best is 0.1%.

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

The Bi ₂ O ₃ component is any component that can increase the refractive index and lower the glass transition point when the content exceeds 0%.

On the other hand, by setting the content of the Bi ₂ O ₃ component to 5.0% or less, coloring of the glass can be suppressed and devitrification resistance can be improved. Therefore, the upper limit of the content of the Bi ₂ O ₃ component is preferably 5.0%, more preferably 3.0%, more preferably 1.0%, and most preferably 0.1%.

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

The TeO ₂ component is any component that can increase the refractive index and lower the glass transition point when the content is greater than 0%. On the other hand, when the glass raw material is melted using a crucible made of platinum or a melting tank in which the part in contact with the molten glass is made of platinum, there is a problem that the TeO ₂ component may be alloyed with platinum.

Therefore, the upper limit of the content of the TeO ₂ component is preferably 5.0%, more preferably 3.0%, more preferably 1.0%, and most preferably 0.1%.

TeO ₂ component, TeO ₂ etc. can be used as raw materials.

The SnO ₂ component is any component that, when the content is greater than 0%, can reduce the oxidation of molten glass, clarify the glass, and improve the visible light transmittance of the glass.

On the other hand, by setting the content of the SnO ₂ component to 3.0% or less, glass coloring or glass devitrification caused by reduction of molten glass can be reduced. In addition, since the SnO ₂ component is less alloyed with the melting equipment (especially noble metals such as Pt), the service life of the melting equipment can be expected to be extended. Therefore, the upper limit of the SnO ₂ component content is preferably 3.0%, more preferably 1.0%, more preferably 0.5%, and most preferably 0.1%.

As the SnO ₂ component, SnO, SnO ₂ , SnF ₂ , SnF ₄ , etc. can be used as raw materials.

The Sb ₂ O ₃ component is any component capable of defoaming molten glass when its content is greater than 0%.

On the other hand, if the content of the Sb ₂ O ₃ component is too high, the transmittance in the short wavelength region of the visible light region will deteriorate. Therefore, the upper limit of the content of the Sb ₂ O ₃ component is preferably 1.0%, more preferably 0.7%, more preferably 0.5%, still more preferably 0.2%, and most preferably 0.1%.

As the Sb ₂ O ₃ component, Sb ₂ O ₃ , Sb ₂ O ₅ , and Na ₂ H ₂ Sb ₂ O ₇ can be used. 5H ₂ O etc. as raw materials.

In addition, the component that clarifies and defoams the glass is not limited to the above-mentioned Sb ₂ O ₃ component, and clarifiers, defoaming agents, or combinations thereof that are known in the field of glass manufacturing can be used.

The CeO ₂ component is a component that clarifies glass and is an optional component in the optical glass of the present invention. In particular, if the CeO ₂ component is set to 1.0% or less, visible light coloring can be suppressed.

Therefore, the upper limit of the content of the CeO ₂ component relative to the total mass of the glass converted into oxides is preferably 1.0%, more preferably 0.7%, and more preferably 0.5%.

The CeO ₂ component can be contained in the glass using, for example, CeO ₂ , Ce(OH) ₃ or the like as a raw material.

The Fe ₂ O ₃ component is a component that clarifies glass and is an optional component in the optical glass of the present invention. In particular, by setting the Fe ₂ O ₃ component to 0.5% or less, visible light coloring can be suppressed. Therefore, the upper limit of the content of the Fe ₂ O ₃ component based on the total mass of the glass in terms of oxide composition is preferably 0.5%, and more preferably 0.1%.

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

The Ag ₂ O component is a component that adjusts the crystallization and penetration characteristics of glass, and is an optional component in the optical glass of the present invention. In particular, by setting the Ag ₂ O component to 3.0% or less, visible light coloring can be suppressed.

Therefore, the upper limit of the content rate of the Ag ₂ O component relative to the total mass of the glass in terms of oxide composition is preferably 3.0%, more preferably 1.0%, more preferably 0.5%, and still more preferably 0.1%.

The Ag ₂ O component can be contained in the glass using, for example, Ag ₂ O or the like as a raw material.

When the content of the F component is greater than 0%, it can increase the Abbe number of the glass, lower the glass transition point, and improve the devitrification resistance.

However, if the content of the F component, that is, the total amount of F as a fluoride that partially or completely replaces one or more oxides of each metal element, is greater than 15.0%, the volatilization of the F component will occur. The amount increases, so it becomes difficult to obtain stable optical constants and it is difficult to obtain homogeneous glass.

Therefore, the upper limit of the content of component F is preferably 15.0%, more preferably 10.0%, more preferably 8.0%, still more preferably 5.0%, still more preferably 3.0%, and most preferably 1.0%.

The F component can be contained in the glass by using, for example, ZrF ₄ , AlF ₃ , NaF, CaF ₂ , etc. as raw materials.

The sum (mass sum) of the RO component (in the formula, R is one or more selected from the group consisting of Mg, Ca, Sr, and Ba) is preferably 10.0% or less. This can suppress deterioration of chemical durability or decrease in devitrification resistance due to excess content.

Therefore, the upper limit of the mass sum of the RO components is preferably 10.0%, more preferably 8.0%, more preferably 6.0%, still more preferably 4.0%, still more preferably 2.0%, still more preferably 1.0 %.

The total content (mass sum) of the Ln ₂ O ₃ component (where Ln is one or more selected from the group consisting of La, Gd, Y, and Lu) is preferably 25.0% or less. Thereby, since the liquidus temperature of the glass becomes lower, the devitrification of the glass can be reduced. Therefore, the upper limit of the mass sum of the Ln ₂ O ₃ component is preferably 25.0%, more preferably 20.0%, more preferably 15.0%, and most preferably 10.0%.

The total amount of the B ₂ O ₃ component and the ZnO component is preferably less than 99.5%. Thereby, deterioration of chemical durability can be suppressed. Therefore, the mass sum (B ₂ O ₃ +ZnO) is preferably less than 99.5%, more preferably less than 98.5%, more preferably less than 98.0%, still more preferably less than 97.2%, still more preferably Below 97.0%, the best is below 96.5%.

The ratio of the B ₂ O ₃ component content to the total content of the SiO ₂ component and the Al ₂ O ₃ component is preferably 1.0 or more. By increasing this ratio, deterioration of meltability can be suppressed. Therefore, the mass ratio B ₂ O ₃ /(SiO ₂ +Al ₂ O ₃ ) is preferably 1.0 or more, more preferably more than 2.0, more preferably more than 2.5, still more preferably more than 3.0, still more preferably greater than 5.0.

Furthermore, by setting the mass ratio to 100 or less, deterioration of chemical durability can be suppressed. Therefore, the mass ratio is preferably 100.0 or less, preferably 80.00 or less, more preferably 60.0 or less, still more preferably 40.0 or less, still more preferably 30.0 or less, and most preferably 20.0 or less.

The content ratio of the B ₂ O ₃ component to the ZnO component is preferably 1.5 or less. By reducing this ratio, a glass material with excellent devitrification resistance can be obtained. Therefore, the mass ratio B ₂ O ₃ /ZnO is preferably 1.5 or less, more preferably 1.0 or less, more preferably 0.8 or less, and most preferably 0.6 or less.

<About ingredients that should not be included>

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

Other components may be added as necessary within the scope that does not affect the properties of the glass of the present invention. However, in addition to Ti, Zr, Nb, W, La, Gd, Y, Yb, Lu, When various transition metal components such as V, Cr, Mn, Co, Ni, Cu and Mo are contained individually or in a composite form, even a small amount will still color the glass and produce absorption at specific wavelengths in the visible region. properties, therefore, especially in optical glass using wavelengths in the visible region, it is preferable that it does not substantially contain it.

Since the Nd ₂ O ₃ component has a great influence on the coloring of the glass, it is ideal that it does not contain it substantially, that is, it does not contain any of these components except for unavoidable mixing.

Since the Er ₂ O ₃ component has a great influence on the coloring of the glass, it is ideal that it does not substantially contain it, that is, it does not contain any of these components except for unavoidable mixing.

In addition, since lead compounds such as PbO are components with a high environmental load, it is ideal to substantially not contain them. That is, except for unavoidable mixing, no such components should be included.

In addition, since As ₂ O ₃ and other arsenic compounds are components with high environmental load, it is ideal to substantially not contain them, that is, not to contain any of these components except for unavoidable mixing.

Furthermore, the components Th, Cd, Tl, Os, Be, and Se have been regarded as harmful chemical substances in recent years, and there is a tendency to avoid their use, not only in the glass manufacturing steps, but also in the processing steps and after productization. must be dealt with according to environmental countermeasures. Therefore, from the viewpoint of attaching importance to the impact on the environment, it is preferable that these ingredients are not contained substantially.

[physical properties]

The optical glass of the present invention preferably has a high refractive index and a high Abbe number (low dispersion). In particular, the lower limit of the refractive index (n _d ) of the optical glass of the present invention is preferably 1.63, more preferably 1.65, and more preferably 1.66. The upper limit of the refractive index (n _d ) is preferably 1.77, more preferably 1.75, more preferably 1.70, and most preferably 1.68.

In addition, the lower limit of the Abbe number (ν _d ) of the optical glass of the present invention is preferably 33, more preferably 38, more preferably 40, still more preferably 43, and most preferably 45. The upper limit of the Abbe number (ν _d ) is preferably 55, but the upper limit is preferably 54, more preferably 53, still more preferably 52, still more preferably 51, and most preferably 50.

By having such a high refractive index, a large amount of light refraction can be obtained even if an optical element is attempted to be thinned. In addition, by having such low dispersion, when used as a single lens, focus deviation (chromatic aberration) caused by the wavelength of light can be reduced. Therefore, when an optical system is constructed in combination with an optical element having high dispersion (low Abbe number), for example, the optical system as a whole can reduce aberrations and expect high imaging characteristics and the like.

As mentioned above, the optical glass of the present invention can play an important role in optical design. Especially when constructing optical systems, in addition to expecting high imaging characteristics, it can also achieve miniaturization of the optical system, thereby expanding the scope of optical design. degree of freedom.

The optical glass of the present invention preferably has a small specific gravity. More specifically, the optical glass of the present invention has a specific gravity of 5.00 or less. This can reduce the quality of the optical element or the optical machine using the optical element, thereby contributing to the weight reduction of the optical machine. Therefore, the upper limit of the specific gravity of the optical glass of the present invention is preferably 5.00 or less, preferably 4.60, more preferably 4.20, even more preferably 4.10, and most preferably 3.80. In addition, the specific gravity of the optical glass of the present invention is usually about 2.80 or more, specifically 3.10 or more, and more specifically 3.30 or more.

The specific gravity of the optical glass of the present invention is measured according to the Japan Optical Glass Industry Association standard JOGIS05-1975 "Measurement method of specific gravity of optical glass".

The optical glass of the present invention preferably has high devitrification resistance, and more specifically, has a low liquidus temperature.

That is to say, the upper limit of the liquidus temperature of the optical glass of the present invention is preferably 1150°C, preferably 1100°C, more preferably 1050°C, still more preferably 1000°C, still more preferably 950°C, and most preferably The best is 900℃.

In this way, even if the molten glass flows out at a lower temperature, due to the The crystallization of the glass is reduced, so the devitrification when forming the glass from the molten state can be reduced, and the impact on the optical properties of optical elements using glass can be reduced. In addition, since the glass can be formed even if the melting temperature of the glass is lowered, the energy consumed when forming the glass can be suppressed, thereby reducing the manufacturing cost of the glass.

On the other hand, the lower limit of the liquidus temperature of the optical glass of the present invention is not particularly limited, but the liquidus temperature of the glass obtained by the present invention is usually about 650°C or higher, specifically 700°C or higher, and more Specifically, it is above 750°C.

In addition, the "liquidus temperature" in this specification means that the glass is placed in a temperature gradient furnace with a temperature gradient of 650°C to 1150°C and held for 30 minutes. After it is taken out of the furnace and cooled, the glass is heated to a magnification of 100 times. The lowest temperature at which no crystallization is observed when crystallization is observed under a microscope.

The optical glass of the present invention preferably has an average linear thermal expansion coefficient α at 100°C to 300°C of 100 (10 ^-7 °C ^-1 ) or less.

That is, the upper limit of the average linear thermal expansion coefficient α at 100°C to 300°C of the optical glass of the present invention is preferably 100 (10 ^-7 ℃ ^-1 ) or less, preferably 60 or less, and more preferably 55 or less , and more preferably, it is less than 53, and still more preferably, it is less than 50.

This can improve thermal shock resistance or enable joining with metals that comply with the average linear thermal expansion coefficient.

[Manufacturing method]

The optical glass of the present invention can be produced in the following manner, for example. That is, the above-mentioned raw materials are uniformly mixed so that each component is within the prescribed content range, and then the prepared mixture is put into a platinum crucible, and the temperature is set to 1100°C to 1340°C according to the ease of melting of the glass composition. The optical glass of the present invention is produced by using an electric furnace in the range of 1 hour to 6 hours to melt, stir and homogenize, then cool to an appropriate temperature, cast in a mold, and then slowly cooled.

[Shaping of glass]

The glass of the present invention can be melted and formed by known methods. Additionally, for The method of forming the glass melt is not limited.

[Glass molded bodies and optical components]

The glass of the present invention can be produced into a glass molded body using, for example, grinding and grinding processing methods. That is, glass can be subjected to mechanical processing such as grinding and grinding to produce a glass molded body. In addition, the method of manufacturing the glass formed body is not limited to these methods.

[Example]

The composition of the examples and comparative examples of the glass of the present invention, the refractive index ( _nd ), Abbe number (ν _d ), specific gravity (d), and average linear thermal expansion coefficient (α) between 100°C and 300°C of the glass ), and the liquidus temperature are shown in Table 1 to Table 11. In addition, the following examples are only for illustrative purposes, and the present invention is not limited to these examples.

The raw materials of each component of the glass in the embodiments and comparative examples of the present invention are selected from high-quality materials used in general optical glasses such as oxides, hydroxides, carbonates, nitrates, fluorides, and meta-acid compounds. The purity raw materials were weighed and mixed uniformly so as to have the composition ratio of each example shown in the table, and then put into a platinum crucible, and the temperature was set to 1100°C to 1350°C according to the ease of melting of the glass composition. After melting in an electric furnace in the ℃ range for 2 hours to 5 hours, the glass is stirred to homogenize, cast in a mold, etc., and slowly cooled to produce glass.

The refractive index (n _d ) and Abbe's number (ν _d ) of the glass in Examples are expressed as measured values relative to the d line (587.56 nm) of a helium lamp. In addition, the Abbe number (ν _d ) is calculated using the refractive index of the d line mentioned above, the refractive index with respect to the F line (486.13 nm) of the hydrogen lamp (n _F ), and the refractive index with respect to the C line (656.27 nm) ( The value of n _C ) is calculated from the equation of Abbe's number (ν _d )=[(n _d -1)/(n _F -n _C )].

The specific gravity of the glass in the examples and comparative examples is based on the Japan Optical Glass Industry Association It will be measured according to the standard JOGIS05-1975 "Measurement method of specific gravity of optical glass".

In addition, the liquidus temperature of the glass of the Examples and Comparative Examples was determined according to the following method. That is, the glass of the Examples and Comparative Examples was placed in a temperature gradient furnace with a temperature gradient of 650°C to 1150°C and held for 30 minutes. After being taken out of the furnace and cooled, the values were determined by observation with a microscope at a magnification of 100 times. The lowest temperature at which no crystallization was observed with or without crystallization.

In addition, when it is described as "800°C or less", it means that no crystal is observed at least in a state of 800°C.

In addition, the average linear thermal expansion coefficient α (100°C to 300°C) of the glass in the examples and comparative examples was measured in accordance with the Japan Optical Glass Industry Association standard "Measurement method of thermal expansion of optical glass" JOGIS08-2003.

As shown in the table, in the optical glass according to the embodiment of the present invention, the B ₂ O ₃ composition is 20.0% to 45.0%, the ZnO composition is 35.0% to 66.0%, the SiO ₂ composition is 0% to less than 15.0%, and the Al ₂ O _{The 3} component is 0% to 10.0%, the Rn ₂ O component is 0% to 3.0% (in the formula, Rn is one or more species selected from the group consisting of Li, Na, and K), and the mass product (Rn ₂ O × SiO ₂ ) is 0 to less than 10.0, so it has the desired optical constant, and optical glass with a small expansion coefficient at 100°C to 300°C can be obtained.

In addition, the refractive index (n _d ) of the optical glass according to the embodiment of the present invention is 1.63 or more, more specifically, 1.65 or more, and the refractive index (n _d ) is 1.77 or less, which is within the desired range. within the range.

In addition, regardless of the optical glass according to the embodiment of the present invention, the Abbe number (ν _d ) is 55 or less, and the Abbe number (ν _d ) is also 33 or more, more specifically, 38 or more, all of which are within within the expected range.

In addition, the optical glass of the present invention forms stable glass and is less likely to devitrify during the production of the glass. This phenomenon can also be inferred from the fact that the liquidus temperature of the optical glass of the present invention is 1150°C or lower, more specifically, 1100°C or lower.

In addition, the average linear thermal expansion coefficient α at 100°C to 300°C of the optical glass according to the embodiment of the present invention is 100 (10 ^-7 °C ^-1 ) or less. Therefore, it can be clearly seen that the average linear thermal expansion coefficient of the optical glass according to the embodiment of the present invention is low.

In addition, the specific gravity of any optical glass according to the embodiment of the present invention is 5.00 or less. Therefore, it can be clearly seen that the specific gravity of the optical glass according to the embodiment of the present invention is small.

Therefore, the refractive index (n _d ) and Abbe number (ν _d ) of the optical glass according to the embodiment of the present invention are within the expected range, the liquidus temperature is below 1150°C, and the average linear thermal expansion coefficient α is 100 ( 10 ^-7 ℃ ^-1 ) or less. Therefore, it can be clearly seen that the expansion coefficient of the optical glass according to the embodiment of the present invention is low.

Furthermore, the optical glass of the embodiment of the present invention is used to form a glass block, and the glass block is ground and polished to be processed into the shape of a lens and a lens. As a result, various lens and lens shapes can be stably processed.

Although the present invention has been described in detail for the purpose of illustration above, the purpose of this embodiment is only for illustration. It should be understood by those with ordinary knowledge in the technical field that without departing from the spirit and scope of the present invention, The invention is still susceptible to many variations.

Claims (11)

An optical glass, in terms of mass %: B ₂ O ₃ composition is 20.0% to 45.0%; ZnO composition is 35.0% to 66.0%; SiO ₂ composition is 0% to less than 15.0%; Al ₂ O ₃ composition is 0% to 10.0%; Rn ₂ O composition is 0% to 3.0%; La ₂ O ₃ composition is 0% to 5.0%; TiO ₂ composition is 0% to 2.0%; Nb ₂ O ₅ composition is 0% to 1.0%; ZrO ₂ components are 0% to 1.0%; Rn is one or more species selected from the group consisting of Li, Na, and K; the mass product (Rn ₂ O×SiO ₂ ) is 0 to 10.0; the refractive index (n _d ) is 1.63 to 1.77, the Abbe number (ν _d ) is 33 to 55; the average linear thermal expansion coefficient α at 100°C to 300°C is 100 (10 ^-7 °C ^-1 ) or less. The optical glass as described in claim 1, wherein in terms of mass %: the Li ₂ O component is 0% to 3.0%; the Na ₂ O component is 0% to 3.0%; and the K ₂ O component is 0% to 3.0%. Optical glass as described in claim 1 or 2, in which in terms of mass %: the Y ₂ O ₃ component is 0% to 15.0%; the Gd ₂ O ₃ component is 0% to 15.0%; the Lu ₂ O ₃ component is 0% to 1.0%; Yb ₂ O ₃ composition is 0% to 1.0%; Ta ₂ O ₅ composition is 0% to 5.0%; WO ₃ composition is 0% to 5.0%; MgO composition is 0% to 10.0%; CaO composition is 0% to 10.0%; SrO composition is 0% to 10.0%; BaO composition is 0% to 10.0%; GeO ₂ composition is 0% to 5.0%; Ga ₂ O ₃ composition is 0% to 5.0%; P ₂ O ₅ The composition is 0% to 10.0%; the Bi ₂ O ₃ composition is 0% to 5.0%; the TeO ₂ composition is 0% to 5.0%; the SnO ₂ composition is 0% to 3.0%; the Sb ₂ O ₃ composition is 0% to 1.0 %; CeO ₂ component is 0% to 1.0%; Fe ₂ O ₃ component is 0% to 0.5%; Ag ₂ O component is 0% to 3.0%; as the oxidation of one or more of the above metal elements The content of F of the fluoride partially or completely replaced by one of the substances is 0 mass % to 15.0 mass %. The optical glass as described in claim 1 or 2, wherein the mass sum of the RO components is 0% to 10.0%, R is one or more selected from the group consisting of Mg, Ca, Sr, and Ba; Ln ₂ O ₃ The mass sum of the components is 0% to 25.0%, and Ln is one or more types selected from the group consisting of La, Gd, Y, and Lu. The optical glass according to claim 1 or 2, wherein the liquidus temperature in the temperature gradient furnace is 1150°C or lower. The optical glass as described in claim 1 or 2, wherein the mass and B ₂ O ₃ + ZnO are less than 99.5%. The optical glass according to claim 1 or 2, wherein the mass ratio B ₂ O ₃ /(SiO ₂ +Al ₂ O ₃ ) is 1.0 or more. The optical glass according to claim 1 or 2, wherein the mass ratio B ₂ O ₃ /ZnO is 1.5 or less. A preformed body member made of the optical glass described in any one of claims 1 to 8. An optical element made of the optical glass described in any one of claims 1 to 8 become. An optical machine provided with the optical element described in claim 10.