JP2024001862A - Optical glass, glass preform, optical element, and optical instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical glass which has a refractive index of 1.53-1.63 and an Abbe number of 54-64 and is suitable for precision press working.

SOLUTION: An optical glass comprises, in wt.%, following components: SiO₂: 25-48%, B₂O₃: 10-30%, Al₂O₃: 1-10%, BaO: 10-30%, ZnO: 2-15%, and Na₂O: 1-10%. Through reasonable component design, the inventive optical glass has an expected refractive index and Abbe number, while having a relatively low transition temperature and yield point temperature, and is suitable for precision press working.

SELECTED DRAWING: None

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention relates to optical glass, and in particular to optical glass having a refractive index of 1.53 to 1.63 and an Abbe number of 54 to 64, suitable for precision press processing, and glass preforms, optical elements, and optical instruments manufactured using the same. It is something.

With the development of the optoelectronic industry, optical elements are required to be smaller, lighter, and have higher performance, and as a result, the demand for aspheric lenses that can improve imaging quality is increasing. . Aspherical lenses are generally manufactured using precision press molding. In this method, a preform is created by cold working a glass material, then the preform is placed in a specially made mold, heated to near its yield point temperature, and the surface structure of the mold is transferred to the glass material by applying pressure. , obtain an aspheric lens with the expected surface texture parameters. During the process from preform manufacturing to aspherical lens plating, glass must be cut, polished, and cleaned several times, and contact with acidic substances is unavoidable. If the acid resistance of the glass is poor, the optical surface of the glass will be destroyed and the product will be discarded. Therefore, the optical glass itself needs to have better oxidation resistance and chemical stability in order to improve the yield rate during processing and plating processes.

Patent Document 1 describes an optical glass for press processing that has a refractive index of 1.55 to 1.60, an Abbe number of 55 to 60, and excellent chemical stability, but the lowest transition temperature (T _g ) published in the example is is 572℃, and too high a transition temperature shortens the service life of the mold and increases energy consumption during stamping.

China Patent Application Publication No. 1201019

The technical problem to be solved by the present invention is to provide an optical glass having a refractive index of 1.53 to 1.63, an Abbe number of 54 to 64, and suitable for precision press processing.

The technical solutions adopted by the present invention to solve the technical problems are as follows.
Optical glass containing the following components in weight%: SiO ₂ : 25-48%; B ₂ O ₃ : 10-30%; Al ₂ O ₃ : 1-10%; BaO: 10-30%; ZnO: 2 ~15%; Na ₂ O: 1~10%.

The optical glass further contains the following components in weight%: La ₂ O ₃ : 0-10%, and/or Li ₂ O: 0-5%, and/or K ₂ O: 0-10%, and /or Gd ₂ O ₃ : 0-5%, and/or Y ₂ O ₃ : 0-5%, and/or SrO: 0-10%, and/or CaO: 0-10%, and/or MgO: 0 to 10%, and/or ZrO ₂ : 0 to 5%, and/or TiO ₂ : 0 to 5%, and/or Nb ₂ O ₅ : 0 to 5%, and/or Ta ₂ O ₅ : 0 to 5%, and/or WO ₃ : 0 to 5%, and/or clarifying agent: 0 to 1%.

Optical glass consisting of the following components in weight percent: SiO ₂ : 25-48%; B ₂ O ₃ : 10-30%; Al ₂ O ₃ : 1-10%; La ₂ O ₃ : 0-10%; BaO: 10-30%; ZnO: 2-15%; Na ₂ O: 1-10%; Li ₂ O: 0-5%; K ₂ O: 0-10%; Gd ₂ O ₃ : 0-5% ; _Y2O3 :0~5%;SrO:0~10%;CaO:0~10%;MgO:0~10 _% ; _ZrO2 :0~5%; _TiO2 :0~5%; _Nb2 O ₅ : 0-5%; Ta ₂ O ₅ : 0-5%; WO ₃ : 0-5%; Clarifying agent: 0-1%.

The optical glass further comprises the following components in weight percent and satisfies one or more of the following six conditions:
1) SiO ₂ /B ₂ O ₃ is 0.85 to 4.5, preferably SiO ₂ /B ₂ O ₃ is 1.0 to 4.3, more preferably SiO ₂ /B ₂ O ₃ is 1.2 to 4.0;
2) B ₂ O ₃ +La ₂ O ₃ is 38% or less, preferably B ₂ O ₃ +La ₂ O ₃ is 36% or less, more preferably B ₂ O ₃ +La ₂ O ₃ is 34% or less .
3) SiO ₂ /(B ₂ O ₃ +ZnO) is 0.6 to 3.7, preferably SiO ₂ /(B ₂ O ₃ +ZnO) is 0.8 to 3.5, more preferably SiO ₂ /(B ₂ O ₃ +ZnO) is 1.0-3.0;
4) 2-15% K ₂ O+Na ₂ O, preferably 3-13% K ₂ O+Na ₂ O, more preferably 4-11% K ₂ O+Na ₂ O;
5) SiO ₂ /(K ₂ O+Na ₂ O) is 1.7 to 22.0, preferably SiO ₂ /(K ₂ O+Na ₂ O) is 1.8 to 20.0, more preferably SiO ₂ /(K ₂ O+Na ₂ O) is 2.0 to 18.0;
6) Li ₂ O/B ₂ O ₃ is 0 to 0.45, preferably Li ₂ O/B ₂ O ₃ is 0 to 0.4, more preferably Li ₂ O/B ₂ O ₃ is 0 to 0.35.

The optical glass further comprises the following components in weight percent: SiO ₂ : 27-46%, preferably SiO ₂ : 29-45%, and/or B ₂ O ₃ : 12-28%, preferably B ₂ O ₃ : 14-26%, and/or Al ₂ O ₃ : 1.5-8%, preferably Al ₂ O ₃ : 2-6%, and/or La ₂ O ₃ : 0-8%, preferably La ₂ O ₃ : 0 to 6%, and/or BaO: 12 to 29%, preferably BaO: 13 to 28%, and/or ZnO: 3 to 14%, preferably ZnO: 4 to 13%, and/or Li ₂ O: 0-4%, preferably Li ₂ O: 0-3%, and/or Na ₂ O: 1.5-9%, preferably Na ₂ O: 2-8%, and/or K ₂ O: 0 ~8%, preferably K ₂ O: 0-6%, and/or Gd ₂ O ₃ : 0-2%, and/or Y ₂ O ₃ : 0-2%, and/or SrO: 0-5%. , and/or CaO: 0 to 5%, preferably CaO: 0 to 2%, and/or MgO: 0 to 5%, and/or ZrO ₂ : 0 to 2%, and/or TiO ₂ : 0 to 2. %, and/or Nb ₂ O ₅ : 0-2%, and/or Ta ₂ O ₅ : 0-2%, and/or WO ₃ : 0-2%, and/or clarifier: 0-0.5%. be.

Furthermore, the component does not contain Gd ₂ O ₃ and/or does not contain Y ₂ O ₃ and/or does not contain SrO and/or does not contain MgO and/or does not contain ZrO ₂ . The above optical glass, which does not contain TiO ₂ and/or does not contain Nb ₂ O ₅ and/or does not contain Ta ₂ O ₅ and/or does not contain WO ₃ .

Further, the optical glass has a refractive index n _d of 1.53 to 1.63, preferably a refractive index n _d of 1.535 to 1.625, more preferably a refractive index n _d of 1.54 to 1.62, and an Abbe number ν _d of 54 to 64, preferably Abbe The number ν _d is 54.5 to 63.5, more preferably the Abbe number ν _d is 55 to 63.

Furthermore, the optical glass has an acid resistance stability D _A of class 4 or higher, preferably class 3 or higher, and/or a transition temperature T _g of 550°C or lower, preferably 540°C or lower, more preferably 530°C or lower, and/or The yield point temperature T _s is 600°C or less, preferably 590°C or less, more preferably 580°C or less, and/or the crystal temperature upper limit T _max is less than 1100°C, preferably less than 1000°C, more preferably less than 900°C, and/or the erosive change amount ΔL is less than 5 mm, preferably less than 4 mm, more preferably less than 3 mm.

A glass preform manufactured using the above optical glass.
An optical element manufactured from the above optical glass or the above glass preform.
An optical device comprising the optical glass described above and/or the optical element described above.

The beneficial effects of the present invention are as follows. Through rational component design, the optical glass obtained by the present invention has the expected refractive index and Abbe number, and at the same time has a relatively low transition temperature and yield point temperature, making it suitable for precision press processing.

[Optical glass]
Below, the range of each component (constituent element) of the optical glass of the present invention will be explained. In this specification, unless otherwise specified, the content of each component is expressed in weight percent based on the total glass material in terms of oxide composition. Here, "converted into an oxide composition" means that the oxide, complex salt, hydroxide, etc. used as the raw material for the optical glass composition of the present invention decomposes during melting and is converted into an oxide. This is when the total weight of the oxide material is taken as 100%. The optical glass of the present invention may also be simply referred to as glass.

Specifically, numerical ranges set forth herein include upper and lower limits, and "greater than" and "less than" include endpoint values, and all whole numbers and fractions included in the range. Including and limiting the range are not intended to be limited to the specific values listed. Reference herein to "and/or" is inclusive, eg, "A and/or B" means only A, only B, or both A and B.

<Essential and optional ingredients>
SiO ₂ is a necessary component of the present invention, is a network former of the glass, and is an important component to maintain the excellent chemical stability of the present invention. When the content of _SiO2 is less than 25%, the chemical stability of the glass not only does not meet the design requirements, but also tends to crystallize when the glass is reheated, and the thermal stability no longer meets the precision stamping requirements. On the other hand, if the SiO ₂ content exceeds 48%, it becomes difficult to refine the glass, and at the same time, if the SiO ₂ content is too high, the yield point temperature of the glass increases, which is disadvantageous for precision press processing. Therefore, the content of SiO ₂ is 25-48%, preferably 27-46%, more preferably 29-45%.

B ₂ O ₃ is a necessary component of the present invention, and also serves as a network former of the glass in the present invention, reducing dispersion, improving processability, and lowering the yield point temperature in the glass. If the content of B ₂ O ₃ is less than 10%, the effect of lowering the yield point temperature is not significant, but if the content exceeds 30%, the erosion of glass equipment during production may be controlled. It becomes difficult. Therefore, the content of B ₂ O ₃ is 10 to 30%, preferably 12 to 28%, more preferably 14 to 26%.

As a result of extensive tests and research, the inventors found that by controlling the ratio SiO ₂ /B 2 O ₃ of SiO ₂ content and B ₂ O ₃ content, the press workability of glass and _the chemical It was found that the design requirements of stability, meltability and erodibility were met. In some embodiments, preferably when SiO ₂ /B ₂ O ₃ is between 0.85 and 4.5, the melting temperature of the glass is relatively low, the pressing temperature is suitable, the chemical stability of the glass is excellent, and the glass The erosiveness of the material is reduced. More preferably, SiO ₂ /B ₂ O ₃ is 1.0 to 4.3, and still more preferably SiO ₂ /B ₂ O ₃ is 1.2 to 4.0.

Al ₂ O ₃ is the network former of the invention and is an essential component of the invention. Adding _Al2O3 to glass can play the role of strengthening the network structure and improving chemical _stability , but its content too high will increase the high-temperature viscosity of the glass, leading to homogenization and It becomes difficult to remove air bubbles. Therefore, the content of Al ₂ O ₃ is 1 to 10%, preferably 1.5 to 8%, more preferably 2 to 6%.

La ₂ O ₃ can adjust the optical constants of the glass, and by adding it to the glass of the present invention, it can significantly improve the refractive index of the glass, while at the same time not having a large effect on the Abbe number. However, since La ₂ O ₃ significantly increases the yield point temperature of glass, it is disadvantageous for precision press processing. Therefore, in the present invention, the content of La ₂ O ₃ is 0 to 10%, preferably 0 to 8%, more preferably 0 to 6%.

_Gd2O3 and _Y2O3 can improve the thermal stability and chemical stability of glass, but _the expensive _{raw material} cost limits the use _{of Gd2O3} and _Y2O3 . Therefore, in the present invention, the content of Gd ₂ O ₃ is 0 to 5%, preferably 0 to 2%, and more preferably no Gd ₂ O ₃ . Further, the content of Y ₂ O ₃ is 0 to 5%, preferably 0 to 2%, and more preferably Y ₂ O ₃ is not included.

When producing glass, both _B2O3 and _La2O3 are strongly corrosive to the glass melting furnace, and if their total content _{is relatively} high, the acid resistance of the glass will be reduced. In some embodiments, preferably the total content of B ₂ O ₃ and La ₂ O ₃ B ₂ O ₃ +La ₂ O ₃ is 38% or less, more preferably 36% or less, even more preferably 34% or less. This makes it possible to reduce the erosion of the glass liquid into the furnace body and at the same time prevent a decrease in the acid resistance of the glass.

BaO can exist stably in a network structure consisting of SiO ₂ and B ₂ O ₃ , and can maintain stability even when the content is large. It is a component that can increase the refractive index of. However, if the content is too high, the chemical stability of the glass will deteriorate and the density of the glass will also increase. Therefore, the BaO content is 10-30%, preferably 12-29%, more preferably 13-28%.

SrO can similarly increase the refractive index of glass, and SrO is more advantageous than BaO in improving the chemical stability of glass. However, SrO is expensive, and if the content is too high, the glass cost will increase significantly. Therefore, the content of SrO is 0 to 10%, preferably 0 to 5%, and more preferably no SrO.

CaO can improve the mechanical performance of glass and reduce the viscosity of glass, but CaO is usually introduced in the form of _CaCO3 and is limited to the existing industrial level, so _CaCO3 has many impurities and cannot be introduced. If it is too high, the glass transmittance will decrease. Therefore, in the present invention, the content of CaO is 0 to 10%, preferably 0 to 5%, and more preferably 0 to 2%.

MgO can improve the weather resistance of glass, but when its content exceeds 10%, the crystallization resistance and stability of glass will decrease, and the cost of glass will increase rapidly. Therefore, the content of MgO is 0 to 10%, preferably 0 to 5%, and more preferably no MgO.

ZnO can improve the chemical stability of the glass and reduce the medium and low temperature viscosity of the glass, and is a necessary component for realizing a relatively low yield point temperature of the glass of the present invention. However, due to the relatively high dispersion of ZnO, if the content is too high, the optical constants may no longer meet the design requirements. Therefore, in the glass of the present invention, the ZnO content is 2 to 15%, preferably 3 to 14%, more preferably 4 to 13%.

In some embodiments, by controlling the ratio SiO ₂ /(B ₂ O ₃ +ZnO) of SiO ₂ and B ₂ O ₃ +ZnO within a range of 0.6 to 3.7, the transition temperature and yield point temperature of the glass can be adjusted. At the same time, it is possible to limit the erosion of B ₂ O ₃ to the refractories in the melting furnace, limit the erosion of ZnO to the platinum part of the melting furnace, and improve the service life of the melting furnace. Therefore, SiO ₂ /(B ₂ O ₃ +ZnO) is preferably 0.6 to 3.7, more preferably SiO ₂ /(B ₂ O ₃ +ZnO) is 0.8 to 3.5, and even more preferably SiO ₂ /(B ₂ O ₃ +ZnO) is 1.0 to 3.0.

_ZrO2 can improve the chemical stability of glass and increase the refractive index of glass, but silicate-based glass has a low carrying capacity for it, and if the content is too high, it is easy to form concretions, and even The thermal stability of the glass deteriorates, causing crystallization problems during precision press processing. Therefore, the ZrO ₂ content of the present invention is 0-5%, preferably 0-2%, and in some embodiments is more preferably free of ZrO ₂ .

_TiO2 and _WO3 can increase the refractive index of the glass and improve the thermal stability of the glass, but the dispersion of the glass will increase rapidly, so the optical constants of the glass will no longer meet the design requirements. Therefore, in the present invention, the content of TiO ₂ is 0 to 5%, preferably 0 to 2%, and more preferably no TiO ₂ . The content of WO ₃ is 0 to 5%, preferably 0 to 2%, and more preferably WO ₃ is not included.

Ta ₂ O ₅ and Nb ₂ O ₅ have the role of increasing the refractive index and devitrification resistance of glass, but compared to other components, Ta ₂ O ₅ and Nb ₂ O ₅ are very expensive and are not practical. It is necessary to reduce its usage as much as possible in consideration of performance and cost. Therefore, in the present invention, the content of Ta ₂ O ₅ is 0 to 5%, preferably 0 to 2%, and more preferably Ta ₂ O ₅ is not included. The content of Nb ₂ O ₅ is 0 to 5%, preferably 0 to 2%, and more preferably no Nb ₂ O ₅ .

K ₂ O can lower the melting temperature and high temperature viscosity of glass, which helps to reduce the difficulty of glass melting. However, K ₂ O increases the coefficient of thermal expansion of glass, increasing the risk of lens cracking during precision press processing. Moreover, if the K ₂ O content is too high, the chemical stability of the glass will deteriorate. Therefore, the content of K ₂ O is 0-10%, preferably 0-8%, more preferably 0-6%.

Na ₂ O can lower the yield point temperature and melting difficulty of glass, but if the Na ₂ O content is too high, the chemical stability of the glass will deteriorate. Therefore, in the glass of the present invention, the content of Na ₂ O is 1 to 10%, preferably 1.5 to 9%, more preferably 2 to 8%.

K ₂ O and Na ₂ O are alkali metal oxides and have the effect of promoting melting, and K ₂ O and Na ₂ O can lower the transition temperature and yield point temperature of glass, but K ₂ O If the total content of Na 2 O and Na ₂ O is too high, the chemical stability of the glass will deteriorate and the glass erodibility will increase. In some embodiments, by controlling the total content of K ₂ O and Na ₂ O, K ₂ O+Na ₂ O, within the range of 2-15%, the glass has a lower transition temperature and yield point temperature. At the same time, it is possible to prevent the chemical stability of the glass from decreasing and the glass corrosivity from increasing. Therefore, preferably K ₂ O + Na ₂ O is 2 to 15%, more preferably K ₂ O + Na ₂ O is 3 to 13%, even more preferably K ₂ O + Na ₂ O is 4 to 11%. .

In some embodiments of the present invention, glass melting can be achieved by controlling the ratio SiO ₂ /(K ₂ O+Na ₂ O) of SiO ₂ and K ₂ O+Na ₂ O within the range of 1.7 to 22.0. It can reduce the difficulty level, lower the yield point temperature, optimize the chemical stability and thermal stability of glass, and reduce the erodibility of glass. Therefore, SiO ₂ /(K ₂ O+Na ₂ O) is preferably 1.7 to 22.0, more preferably SiO ₂ /(K ₂ O+Na ₂ O) is 1.8 to 20.0, even more preferably SiO ₂ /(K ₂ O+Na ₂ O) is 2.0 to 18.0.

Li ₂ O can play the role of lowering the yield point temperature, melting temperature and high temperature viscosity of glass, and compared with other alkali metal oxides, Li ₂ O has a smaller destructive effect on glass chemical stability, making it easier to melt The promotion effect is better. However, the erosion of Li ₂ O into the glass melting furnace is very serious, and if the content is high, it will greatly reduce the service life of the melting furnace. Therefore, the content of Li ₂ O is 0 to 5%, preferably 0 to 4%, more preferably 0 to 3%.

In contrast to Na ₂ O and K ₂ O, Li ₂ O can play a flocculating effect in glass systems, and when the Li ₂ O content is not too high, it can reduce the chemical stability due to B ₂ O ₃ . This can be prevented to some extent. As a result of extensive testing and research, the inventors have found that in some embodiments, the ratio of Li ₂ O to B ₂ O ₃ , Li ₂ O/B ₂ O ₃ , is controlled within the range of 0 to 0.45. We found that glass can have a relatively low yield point temperature and excellent chemical stability. Therefore, Li ₂ O/B ₂ O ₃ is preferably 0 to 0.45, more preferably Li ₂ O/B ₂ O ₃ is 0 to 0.4, and still more preferably Li ₂ O/B ₂ O ₃ is 0 to 0.35. .

One or more components of Sb ₂ O ₃ , SnO ₂ , SnO and CeO ₂ can act as a fining agent to enhance the glass clarification effect, and the content of the fining agent is preferably 1% or less, more preferably 0.5%. % or less. When the content of Sb ₂ O ₃ exceeds 1%, the clarity of the glass tends to decrease, and at the same time, its strong oxidation effect accelerates the deterioration of the mold, therefore, the Sb ₂ O ₃ content in the present invention The content of is 1% or less, preferably 0.5% or less. SnO ₂ and SnO are also used as fining agents, but if their content exceeds 1%, the glass will become colored, and when the glass is heated, softened, and reshaped by press molding, Sn becomes the starting point for crystal nucleation. , has a tendency to devitrify. Therefore, the contents of SnO ₂ and SnO in the present invention are each 1% or less, preferably 0.5% or less, and more preferably not contained. The action and content ratio of CeO ₂ are the same as that of SnO ₂ , and its content is 1% or less, preferably 0.5% or less, and more preferably not included.

In some embodiments, As ₂ O ₃ , Cl compounds, Br compounds, etc. can also be used as fining agents, the content of which is 1% or less, preferably 0.5% or less, respectively, but environmental protection, etc. Considering this, it is preferable that As ₂ O ₃ is not included.

<Ingredients that should not be included>
If necessary, other components not listed above may be contained within a range that does not impair the glass properties of the present invention. However, even if small amounts of transition metal components such as V, Cr, Mn, Fe, Co, Ni, Cu, Ag, and Mo are contained alone or in combination, the glass will be colored and absorb at specific wavelengths in the visible light region. is generated and has the property of reducing the effect of improving visible light transmittance of the present invention, so it is preferable that it is not actually included in optical glasses that require transmittance of wavelengths in the visible light region.

In recent years, the use of Pb, Th, Cd, Tl, Os, Be and Se cations has tended to be controlled as hazardous chemicals, not only in the glass manufacturing process but also in the processing process and treatment of finished products. Efforts to protect the environment are necessary. Therefore, when placing importance on the impact on the environment, it is preferable not to include them unless they are unavoidably mixed. This makes the optical glass free from substances that actually pollute the environment. Therefore, the optical glass of the present invention can be manufactured, processed, and disposed of without taking special environmental measures.

The terms "not added," "not included," and "0%" as used herein mean that this component was not intentionally added as a raw material for the glass of the present invention. However, impurities and components that are not intentionally added as raw materials and/or equipment for manufacturing glass may be present in small amounts or trace amounts in the final glass, and these are also covered by the patent of the present invention. Targeted.

Below, the characteristics of the optical glass of the present invention will be explained.
<Refractive index and Abbe number>
The refractive index (n _d ) and Abbe number (ν _d ) of optical glasses are tested according to the method specified in GB/T 7962.1-2010.
In some embodiments, the optical glass refractive index (n _d ) of the present invention ranges from 1.53 to 1.63, preferably from 1.535 to 1.625, more preferably from 1.54 to 1.62.
In some embodiments, the Abbe number (v _d ) of the optical glasses of the present invention ranges from 54 to 64, preferably from 54.5 to 63.5, more preferably from 55 to 63.

<Acid resistance stability>
The acid stability (D _A ) of optical glasses is tested according to the method specified in GB/T 17129. In the present invention, acid resistance stability is sometimes simply referred to as acid resistance.
In some embodiments, the acid resistance stability (D _A ) of the optical glass of the present invention is 4 or higher, preferably 3 or higher.

<Transition temperature and yield point temperature>
The transition temperature (T _g ) and yield point temperature (T _s ) of optical glass are measured according to the method specified in "GB/T 7962.20-2010".
In some embodiments, the optical glass of the present invention has a transition temperature (T _g ) of 550°C or less, preferably 540°C or less, more preferably 530°C or less.
In some embodiments, the optical glass of the present invention has a yield temperature (T _s ) of 600°C or less, preferably 590°C or less, more preferably 580°C or less.

<Crystal upper limit temperature>
The test method for the upper limit of crystallization temperature (T _max ) is as follows: A glass sample is placed in a 10×10×150 mm ³ platinum crucible, and the crucible is placed in a temperature gradient furnace at 900-1200°C for 4 hours. After that, take it out and let it cool naturally, immediately observe the presence or absence of crystallization on the glass surface and inside the glass, and set the lowest temperature within the set temperature range that corresponds to the area where crystallization is not confirmed as the "crystal temperature upper limit". . It should be noted that this test method is only effective for cases where the upper limit of the crystallization temperature is 900 to 1200℃, and if there are no crystals on the surface or inside the sample after incubation, the upper limit of the crystallization temperature of the sample is confirmed to be less than 900℃.

Glass with a low upper limit of crystallization temperature reduces the risk of crystallization of the manufactured glass even if molten glass flows out at a relatively low temperature, so it reduces the risk of crystallization when forming glass from a molten state. The influence on the optical characteristics of an optical element using glass can be reduced. In addition, a low crystallization temperature can lower the glass forming temperature, reduce energy loss during glass forming, and lower glass manufacturing costs.

The optical glass of the present invention has excellent crystal stability and a low upper limit of crystal temperature (T _max ). In some embodiments, the optical glass of the present invention has an upper limit crystal temperature (T _max ) of less than 1100°C, preferably less than 1000°C, more preferably less than 900°C.

<Erosion>
The erodibility evaluation method of glass is as follows: 41# melted zirconium corundum brick of 20×20×20 ^mm3 is immersed in 1200℃ glass liquid and kept warm for 50 hours, and then the 41# melted zirconium corundum brick is Take out the brick and measure the amount of change in the average side length of the brick, which is defined as the amount of change due to erosion (ΔL). The smaller the ΔL, the lower the erosiveness of the glass to the brick.
The less corrosive the glass, the less damage the glass liquid will do to the melting furnace during production, increasing the service life of the melting furnace, reducing furnace repair time, energy and material loss, and reducing glass manufacturing costs. It is advantageous to lower it.
The optical glass of the present invention is characterized by low corrosivity. In some embodiments, the optical glass of the present invention has an erodible change (ΔL) of less than 5 mm, preferably less than 4 mm, and more preferably less than 3 mm.

[Glass preform and optical element]
A glass preform can be manufactured from optical glass created using a press molding method such as direct drop molding, polishing, or hot press molding. That is, we can manufacture molten optical glass into precision glass preforms by direct precision drop molding, we can manufacture glass preforms by mechanical processing such as grinding and polishing, or we can use optical glass to create preform blanks for press molding. This preform blank is then hot-pressed and polished to produce a glass preform. It should be noted that the means for manufacturing the optical preform is not limited to the above-mentioned means.

As described above, the optical glass of the present invention is useful for various optical elements and optical designs, and in particular, a blank is formed from the optical glass of the present invention, and this blank is used for hot press molding, precision press molding, etc. It is preferable to produce optical elements such as lenses, prisms, etc.
Both the optical preform and the optical element of the present invention are formed from the optical glass of the present invention. The optical preform of the present invention has the excellent properties of optical glass, and the optical element of the present invention has the excellent properties of optical glass, and various lenses with high optical value, Optical elements such as prisms can be provided.

Examples of lenses include various lenses such as concave meniscus lenses, convex meniscus lenses, biconvex lenses, biconcave lenses, plano-convex lenses, and plano-concave lenses, each having a spherical or aspheric lens surface. The lens according to the invention further includes a lens for an automobile lamp.

[Optical equipment]
The optical element made of optical glass of the present invention can be used for manufacturing optical equipment including, but not limited to, photographic devices, imaging devices, projection devices, display devices, vehicle-mounted devices (including lamps), monitoring devices, etc. .

Hereinafter, for the reference of those skilled in the art, the present invention will be explained in more detail through examples listed in the table. Note that the content of the glass component in Examples 1 to 40# is expressed in weight %, and the protection scope of the present invention is not limited to the above examples.
The optical glasses listed in Tables 1 to 4 (Examples 1 to 40#) are made of general raw materials for optical glasses (oxides, hydroxides, Carbonates, nitrates, sulfates, boric acid, etc.) are weighed and mixed, the mixed raw materials are placed in a platinum crucible, and melted at 1250℃ to 1400℃ for 2 to 5 hours. Thereafter, it is clarified, stirred, and homogenized to obtain a homogeneous molten glass free of bubbles and undissolved substances, and this molten glass is cast in a mold and annealed to produce it.
In Tables 1 to 4, the value of SiO ₂ /B ₂ O ₃ is A1, the value of B ₂ O ₃ +La ₂ O ₃ is A2, the value of SiO ₂ /(B ₂ O ₃ +ZnO) is A3, K The value of ₂ O+Na ₂ O is indicated by A4, the value of SiO ₂ /(K ₂ O+Na ₂ O) is indicated by A5, and the value of Li ₂ O/B ₂ O ₃ is indicated by A6.

<Glass preform example>
The optical glasses obtained in Examples 1 to 40# are cut to a predetermined size, and after uniformly applying a mold release agent to the surface, they are heated, softened, and pressure molded to form concave meniscus lenses and convex meniscus lenses. We manufacture preform blanks for various lenses and prisms, including biconvex lenses, biconcave lenses, plano-convex lenses, and plano-concave lenses. These blanks are also cleaned, ground, polished, and polished to produce preforms.

<Optical element example>
The glass preform is heated and pressure-molded using precision press processing equipment to produce lenses and prisms of various shapes, such as concave meniscus lenses, convex meniscus lenses, biconvex lenses, biconcave lenses, plano-convex lenses, and plano-concave lenses. An antireflection film can also be applied to the surface of the obtained optical element.

<Example of optical equipment>
Optical elements manufactured in the above optical element embodiments can be used in imaging devices, sensors, microscopes, pharmaceutical technology, digital It can be used in projection, communications, optical communication technology/information transmission, optics/illumination in the automotive field, photolithography technology, excimer lasers, wafers, computer chips and integrated circuits and electronic devices containing such circuits and chips.

Claims (16)

Optical glass containing the following components in weight%: SiO ₂ : 25-48%; B ₂ O ₃ : 10-30%; Al ₂ O ₃ : 1-10%; BaO: 10-30%; ZnO: 2 ~15%; Na ₂ O: 1~10%. The optical glass according to claim 1, further comprising the following components in weight%: La ₂ O ₃ : 0 to 10%, and/or Li ₂ O: 0 to 5%, and/or K ₂ O: 0 to 10%, and/or Gd ₂ O ₃ : 0 to 5%, and/or Y ₂ O ₃ : 0 to 5%, and/or SrO: 0 to 10%, and/or CaO: 0 to 10%, and /or MgO: 0 to 10%, and/or ZrO ₂ : 0 to 5%, and/or TiO ₂ : 0 to 5%, and/or Nb ₂ O ₅ : 0 to 5%, and/or Ta ₂ O ₅ : 0 to 5%, and/or WO ₃ : 0 to 5%, and/or clarifying agent: 0 to 1%. Optical glass consisting of the following components in weight percent: SiO ₂ : 25-48%; B ₂ O ₃ : 10-30%; Al ₂ O ₃ : 1-10%; La ₂ O ₃ : 0-10%; BaO: 10-30%; ZnO: 2-15%; Na ₂ O: 1-10%; Li ₂ O: 0-5%; K ₂ O: 0-10%; Gd ₂ O ₃ : 0-5% ; _Y2O3 :0~5%;SrO:0~10%;CaO:0~10%;MgO:0~10 _% ; _ZrO2 :0~5%; _TiO2 :0~5%; _Nb2 O ₅ : 0-5%; Ta ₂ O ₅ : 0-5%; WO ₃ : 0-5%; Clarifying agent: 0-1%. Optical glass according to claim 1, comprising in weight percent the following components and satisfying one or more of the following six conditions:
1) SiO ₂ /B ₂ O ₃ is 0.85 to 4.5;
2) B ₂ O ₃ +La ₂ O ₃ is 38% or less;
3) SiO ₂ /(B ₂ O ₃ +ZnO) is 0.6 to 3.7;
4) K ₂ O + Na ₂ O 2-15%;
5) SiO ₂ /(K ₂ O+Na ₂ O) is 1.7 to 22.0;
6) Li ₂ O/B ₂ O ₃ is 0 to 0.45. Optical glass according to claim 1, comprising in weight percent the following components and satisfying one or more of the following six conditions:
1) SiO ₂ /B ₂ O ₃ is 1.0 to 4.3;
2) B ₂ O ₃ +La ₂ O ₃ is 36% or less;
3) SiO ₂ /(B ₂ O ₃ +ZnO) is 0.8 to 3.5;
4) K ₂ O + Na ₂ O 3-13%;
5) SiO ₂ /(K ₂ O+Na ₂ O) is 1.8 to 20.0;
6) Li ₂ O/B ₂ O ₃ is 0 to 0.4. Optical glass according to claim 1, comprising in weight percent the following components and satisfying one or more of the following six conditions:
1) SiO ₂ /B ₂ O ₃ is 1.2 to 4.0;
2) B ₂ O ₃ +La ₂ O ₃ is 34% or less;
3) SiO ₂ /(B ₂ O ₃ +ZnO) is 1.0 to 3.0;
4) K ₂ O + Na ₂ O 4-11%;
5) SiO ₂ /(K ₂ O+Na ₂ O) is 2.0 to 18.0;
6) Li ₂ O/B ₂ O ₃ is 0 to 0.35. Optical glass according to claim 1, comprising the following components in weight %: SiO ₂ : 27-46%, and/or B ₂ O ₃ : 12-28%, and/or Al ₂ O ₃ : 1.5-8. %, and/or La ₂ O ₃ : 0 to 8%, and/or BaO: 12 to 29%, and/or ZnO: 3 to 14%, and/or Li ₂ O: 0 to 4%, and/or Na ₂ O: 1.5 to 9%, and/or K ₂ O: 0 to 8%, and/or Gd ₂ O ₃ : 0 to 2%, and/or Y ₂ O ₃ : 0 to 2%, and/or SrO: 0 to 5%, and/or CaO: 0 to 5%, and/or MgO: 0 to 5%, and/or ZrO ₂ : 0 to 2%, and/or TiO ₂ : 0 to 2%, and / or Nb ₂ O ₅ : 0 to 2%, and/or Ta ₂ O ₅ : 0 to 2%, and/or WO ₃ : 0 to 2%, and/or clarifier: 0 to 0.5%. Optical glass according to claim 1, comprising the following components in weight %: SiO ₂ : 29-45%, and/or B ₂ O ₃ : 14-26%, and/or Al ₂ O ₃ : 2-6. %, and/or La ₂ O ₃ : 0 to 6%, and/or BaO: 13 to 28%, and/or ZnO: 4 to 13%, and/or Li ₂ O: 0 to 3%, and/or Na ₂ O: 2-8%, and/or K ₂ O: 0-6%, and/or CaO: 0-2%. Optical glass according to claim 1: whose components are free of Gd ₂ O ₃ and/or free of Y ₂ O ₃ and/or free of SrO and/or free of MgO and/or or does not contain ZrO ₂ and/or does not contain TiO ₂ and/or does not contain Nb ₂ O ₅ and/or does not contain Ta ₂ O ₅ and/or does not contain WO ₃ . The optical glass has a refractive index n _d of 1.53 to 1.63, an Abbe number ν _d of 54 to 64, and/or an acid resistance stability D _A of class 4 or higher, and/or a transition temperature T _g of 550° C. or lower, and/or The optical glass according to claim 1, wherein the yield point temperature T _s is 600° C. or less, and/or the upper limit value T _max of the crystallization temperature is less than 1100° C., and/or the erodible change amount ΔL is less than 5 mm. The optical glass has a refractive index n _d of 1.54 to 1.62, and/or an Abbe number ν _d of 55 to 63, and/or an acid resistance stability D _A of class 3 or higher, and/or a transition temperature T _g of 530° C. or lower, The optical glass according to claim 1, wherein the yield point temperature T _s is 580° C. or less, and/or the upper limit crystal temperature T _max is less than 900° C., and/or the erosive change amount ΔL is less than 3 mm. A glass preform manufactured from the optical glass according to any one of claims 1 to 11. An optical element manufactured from the optical glass according to any one of claims 1 to 11. An optical element manufactured with the glass preform according to claim 12. An optical device comprising the optical glass according to any one of claims 1 to 11. An optical device comprising the optical element according to claim 13.