CN115974403A - Optical glass, glass preform, optical element and optical instrument - Google Patents

Abstract

The invention provides an optical glass whose refractive index n _d ranges from 1.55 to 1.65 and Abbe number ν _d ranges from ₅₆ to 65. ₂ O ₃ : 20-50%, Al ₂ O ₃ : 0-10%, La ₂ O ₃ : 0-10%, BaO: 10-30%, ZnO: 2-15%, Li ₂ O: 2-12 %. The present invention reduces the glass transition temperature by optimizing the content of alkaline earth metal oxides and network formers, adjusting the content of Li ₂ O and B ₂ O ₃ , and introduces an appropriate proportion of Al ₂ O ₃ and ZnO to improve the chemical stability of the glass, and obtains an excellent Optical glass for precision molding with excellent chemical stability and low transition temperature.

Description

Optical glass, glass preforms, optical components and optical instruments

This application is a divisional application for the invention patent application with application number 201811375650.9, application date November 19, 2018, and name “Optical glass, glass preforms, optical elements and optical instruments”.

Technical Field

The present invention relates to an optical glass, in particular to an optical glass with a refractive index of 1.55-1.65 and an Abbe number of 56-65, and a glass preform, an optical element and an optical instrument made of the optical glass.

Background Art

With the development of the optoelectronic industry, the requirements for miniaturization, lightness and high performance of optical components have been put forward, which has led to an increasing demand for aspheric lenses that can improve imaging quality. Aspheric lenses are mostly made by precision compression molding. This method is to place the glass material in a special mold and heat it to a temperature of about 10 ⁵ to 10 ⁹ dPa·s. The surface structure of the mold is transferred to the glass material by pressurization, thereby obtaining an aspheric lens with the expected surface parameters. The mold used in this method is made of super-hard alloy material, and the surface shape precision requirements are extremely high, and the production cost is also very high. The higher the working temperature of the compression molding, the greater the possibility of oxidation and scratching of the mold surface. Therefore, in order to extend the service life of the mold, it is expected to use glass materials with low transition temperatures to reduce the compression molding temperature.

In addition, since the refractive index of heavy crown glass is between 1.55 and 1.65 and the Abbe number is between 56 and 65, it usually has very poor acid resistance. During the storage process before coating, the glass will inevitably come into contact with acidic gases. If the acid resistance of the glass is not good, it will damage the optical surface of the glass, which will bring difficulties to the subsequent coating process. Therefore, the optical glass itself needs to have good acid resistance and chemical stability in order to improve the yield rate in the later processing and coating process.

CN1201019A describes an optical glass for molding with a refractive index of 1.55-1.60, an Abbe number of 55-60, and good chemical stability. The lowest transition temperature published in the embodiment is 572°C. Too high a transition temperature will shorten the service life of the mold and increase the energy consumption of the molding process.

Summary of the invention

The technical problem to be solved by the present invention is to provide an optical glass suitable for precision molding with a low transition temperature, a refractive index of 1.55-1.65, and an Abbe number of 56-65, as well as a glass preform, an optical element and an optical instrument made of the optical glass.

The technical solution adopted by the present invention to solve the technical problem is:

₍ 1) Optical glass, the components of which, expressed in percentage by weight, include: _SiO2 : 20-45%, _B2O3 : 20-50% _{, Al2O3} : _0-10 % _, La2O3: 0-10%, BaO: 10-30%, ZnO: 2-15%, _Li2O : 2-12%.

(2) The optical glass according to (1), further comprising, expressed in weight percentage, _{the following} : _Gd2O3 : 0-5%, _Y2O3 : 0-5%, MgO: 0-10%, _SrO : 0-10%, CaO: _0-10 %, ZrO2: 0-10%, TiO2: 0-5%, _WO3 : 0-5%, Ta2O5 _: 0-5%, _Nb2O5 : _0-5 %, _Na2O : _0-10 %, K2O: _0-10 % _{, Sb2O3} : 0-1%.

(3) Optical glass, the components of which are expressed in percentage by _weight : _SiO2 : 20-45%, _B2O3 : 20-50% _{, Al2O3} : 0-10%, La2O3: 0-10%, BaO: 10-30%, ZnO: _{2-15 %} , _Li2O : 2-12%, _Gd2O3 : 0-5%, Y2O3: 0-5%, MgO: 0-10%, SrO: 0-10%, CaO: _{0-10 %} , _ZrO2 : 0-10%, TiO2 _{: 0-5} %, _WO3 : _{0-5 % ,} Ta2O5: 0-5%, _Nb2O5 : 0-5%, Na2O: _0-10 %, _K2O : 0-10 _% , _Sb2O3 : 0-10% : 0～1% composition.

(4) The optical glass according to any one of (1) to (3), wherein SiO ₂ /B ₂ O ₃ is 0.5-2.2, and/or ZnO/3+Li ₂ O is 6-12%, and/or (SiO ₂ +Al ₂ O ₃ )/ZnO is 1.5-25.

(5) The optical glass according to any one of (1) to ( ₄ ), which contains, expressed in weight percentage, 22-43% SiO2, and/or _25-45 % _B2O3 , and/or 2-8% _Al2O3 , and/or 0-8% _La2O3 , and/or 12-28% _BaO , and/or 3-14% ZnO, and/or 3-11% _{Li2O, and/or 0-3% Gd2O3 , and /} or 0-3% _Y2O3 , and/or 0-5% MgO, and/or 0-5% SrO, and/or 0-8% _CaO , and/or 0-5% _ZrO2 , and/ _or 0-2% TiO2, and/or 0-2% _WO3 , and/ _{or Ta2O5} : 0-2%, and/or Nb ₂ O ₅ : 0-2%, and/or Na ₂ O: 0-5%, and/or K ₂ O: 0-5%.

(6) The optical glass according to any one of (1) to (5), wherein the components _, expressed in weight percentage, include: _SiO2 : 25-40%, and/or _B2O3 : 30-40%, and/or _Al2O3 : 3-7%, and/or _La2O3 : 0-6%, and/or _BaO : 14-26%, and/or ZnO: 4-13%, and/or _Li2O : 4-10%, and _/ or CaO: 0-6%.

(7) The optical glass according to any one of (1) to (6), wherein SiO ₂ /B ₂ O ₃ is 0.6-2, and/or ZnO/3+Li ₂ O is 6.5-11%, and/or (SiO ₂ +Al ₂ O ₃ )/ZnO is 1.6-22.

(8) The optical glass according to any one of (1) to (7), wherein SiO ₂ /B ₂ O ₃ is 0.7-1.8, and/or ZnO/3+Li ₂ O is 7-10%, and/or (SiO ₂ +Al ₂ O ₃ )/ZnO is 1.7-20.

(9) The optical glass according to any one of (1) to (8), wherein the composition, expressed in weight percentage, comprises: MgO+CaO+SrO+BaO in _{an amount of 12 to 40%, preferably 13 to 35%, more preferably 14 to 30%; and/or TiO2+WO3+Ta2O5+Nb2O5 in an amount of 0} to 5%, preferably 0 to 2%.

(10) According to any one of (1) to (9), the refractive index (nd) of the optical glass is in the range of 1.55 to 1.65, preferably in the range of 1.57 to 1.63, and more preferably in the range of 1.58 to 1.61; the Abbe number (ν _d ) of the optical glass is in the range of 56 to 65, preferably in the range of 57 to 64, and more preferably in the range of 59 to 62.

(11) The optical glass according to any one of (1) to (10), wherein the acid resistance stability ( _DA ) of the optical glass is Class 4 or higher, preferably Class 3 or higher.

(12) The optical glass according to any one of (1) to (11), wherein the optical glass transition temperature (T _g ) is not higher than 540°C, preferably not higher than 530°C, more preferably not higher than 520°C, and further preferably not higher than 515°C; and/or the upper limit of the crystallization temperature (T _max ) is preferably 1100°C, more preferably 1000°C, further preferably 900°C, and further preferably lower than 900°C.

(13) A glass preform made of the optical glass described in any one of (1) to (12).

(14) An optical element is made of the optical glass described in any one of (1) to (12), or is made of the glass preform described in (13).

(15) An optical instrument comprising the optical glass described in any one of (1) to (12) or the optical element described in (14).

The beneficial effects of the present invention are: by optimizing the content of alkaline earth metal oxides and network formers, adjusting the content of _{Li2O and B2O3} to reduce the glass transition temperature, and introducing appropriate proportions of _Al2O3 and ZnO to improve the chemical stability of the glass, _a precision molded optical glass with excellent chemical stability and low transition temperature is obtained.

DETAILED DESCRIPTION

Ⅰ. Optical glass

Next, the composition range of each component of the optical glass of the present invention is described. In this specification, unless otherwise specified, the content of each component is expressed in weight percentage relative to the total amount of glass material converted into oxide composition. Here, the "composition converted into oxide" means that when the oxides, complex salts and hydroxides used as raw materials for the optical glass components of the present invention decompose and transform into oxides during melting, the total amount of the oxide material is taken as 100%.

Unless otherwise indicated in specific circumstances, the numerical ranges listed herein include upper and lower limits, and "above" and "below" include endpoint values, all integers and fractions within the range, and are not limited to the specific values listed when the range is defined. "And/or" referred to herein is inclusive, for example, "A and/or B" means only A, or only B, or both A and B.

_SiO2 is a glass network generator and the skeleton of optical glass. It has the function of improving the chemical stability of glass and maintaining the anti-crystallization performance of glass. When the _SiO2 content is lower than 20%, it is difficult to achieve the above effect; but when the _SiO2 content is higher than 45%, the glass becomes difficult to melt and the transition temperature required by the present invention cannot be obtained. Therefore, the content of _SiO2 is 20-45%, preferably in the range of 22-43%, and more preferably in the range of 25-40%.

_B2O3 is also a glass network generator, which plays a role in improving the anti-crystallization performance of glass. When _{the B2O3} content is less than ₂₀ %, the crystallization stability of the glass is not ideal; but when _{the B2O3} content is higher than 50%, the chemical stability of the glass will decrease. Therefore, _{the B2O3} content is limited to 20-50%, preferably 25-45%, and more preferably 30-40%.

Although _SiO2 and _B2O3 are both network formers of glass, the structures and functions they form in glass are inconsistent. The ratio of the two network formers is closely related to the internal structure of _the glass. That is to say, in the glass of this system, the ratio of _SiO2 and _B2O3 is closely related to the chemical stability and production performance of the glass. If the _SiO2 / _{B2O3 ratio} is too high, the melting performance of the glass will deteriorate _and the material will become difficult to smelt. If the _SiO2 / _{B2O3 ratio} is too low, the chemical stability of the glass will not meet the design requirements. When the value of _SiO2 / _B2O3 is between 0.5 and _2.2 , the _glass has suitable chemical stability, melting performance and production performance. Therefore, in the optical glass of the present invention, the value of _SiO2 / _B2O3 is 0.5 to 2.2, preferably 0.6 to 2, and more preferably 0.7 to 1.8. In some embodiments, the value of _SiO2 / _B2O3 may be 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7 _{, 1.8, 1.9} , 2.0, 2.1, 2.2.

_Al2O3 can improve the chemical stability of glass, but when its content exceeds 10%, the glass tends _to have poor melting properties and reduced devitrification resistance. Therefore, the content of _{Al2O3 in} the present invention is 0 to 10%, preferably 2 to 8%, and more preferably 3 to 7%.

_A small amount of _La2O3 added to glass can improve the refractive index and dispersion of the glass and improve the weather resistance of the glass, but if the addition amount exceeds 10%, the anti-crystallization performance of the glass will decrease, especially the cost will increase sharply. Therefore, _{the La2O3} content is limited to 0-10%, preferably 0-8%, and more preferably 0-6%.

Gd ₂ O ₃ and Y ₂ O ₃ are helpful for increasing the refractive index and reducing dispersion. In some embodiments, when they partially replace La ₂ O ₃ , they can improve the devitrification resistance and chemical stability of glass. However, the expensive raw material price limits the use of Gd ₂ O ₃ in glass. Therefore, in some embodiments, the content of Gd ₂ O ₃ is 0-5%, preferably 0-3%, and more preferably, it is not contained. In some embodiments, the content of Y ₂ O ₃ ranges from 0-5%, preferably in the range of 0-3%, and in some embodiments, it is preferably not contained.

BaO can improve the refractive index of glass and obtain smaller dispersion; however, if BaO is added in excessive amounts, the anti-crystallization performance and weather resistance of the glass will decrease rapidly. In the present invention, the BaO content is limited to 10-30%, preferably 12-28%, and more preferably 14-26%.

SrO can be added to glass to adjust the refractive index and Abbe number of the glass, but if the amount added is too large, the weather resistance and anti-crystallization performance of the glass will decrease, and the refractive index and Abbe number of the glass will not meet the design expectations. In addition, the price of SrO raw materials is expensive, and excessive introduction will cause the cost of glass to rise rapidly. The SrO content is limited to 0-10%, preferably 0-5%, and in some embodiments, it is preferably not contained.

The introduction of CaO can adjust the refractive index and dispersion of glass, reduce the viscosity of glass, improve the weather resistance of glass, and improve the mechanical strength and hardness of glass. In addition, compared with BaO and SrO, the introduction of CaO is more beneficial to reducing the density of glass, but excessive addition of CaO will lead to a decrease in the anti-crystallization stability of glass. In the present invention, the CaO content is limited to 0-10%, preferably 0-8%, and more preferably 0-6%.

The addition of MgO helps to improve the weather resistance of glass, but when its content is higher than 10%, the anti-crystallization performance and stability of the glass will decrease, and the cost of the glass will increase rapidly. Therefore, the MgO content is limited to 0-10%, preferably 0-5%. In some embodiments, it is preferably not introduced.

BaO, SrO, CaO, and MgO are all alkaline earth metal oxides, and are network exosomes in glass. Their addition to glass can adjust the refractive index and dispersion of glass, reduce the high-temperature viscosity of glass, and enhance the chemical stability of glass. When the total value of BaO, SrO, CaO, and MgO (BaO+SrO+CaO+MgO) is 12 to 40%, high chemical stability of glass can be achieved. In some embodiments, the preferred value of BaO+SrO+CaO+MgO is 13 to 35%, and more preferably 14 to 30%. In some embodiments, the value of BaO+SrO+CaO+MgO may be 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%.

ZnO can improve the chemical stability of glass and reduce the glass transition temperature, but when its content is too high, the devitrification resistance of the glass decreases and the liquidus temperature rises. Therefore, the ZnO content in the glass of the present invention is 2 to 15%, preferably 3 to 14%, and more preferably 4 to 13%.

_ZrO2 can improve the thermal stability of glass and increase the refractive index of glass, but when the content is too high, it will make glass melting difficult. Therefore, the content of _ZrO2 in the present invention is 0-10%, preferably 0-5%, and in some embodiments, it is preferably not contained.

_TiO2 also has the function of increasing the refractive index of glass and can participate in the formation of glass network. The introduction of an appropriate amount makes the glass more stable, but the dispersion of the glass will increase significantly after the introduction, and the transmittance of the short-wave part of the visible light region of the glass will decrease, and the tendency of the glass to be colored will increase. Therefore, the content of _TiO2 in the present invention is 0-5%, preferably 0-2%, and in some embodiments, it is preferably not introduced.

WO ₃ can play a role in increasing the refractive index, but when its content exceeds 5%, the dispersion is significantly increased, and the transmittance of the glass on the short wavelength side of the visible light region is reduced, and the tendency of coloration increases. Therefore, the content of WO ₃ in the present invention is 0 to 5%, preferably 0 to 2%, and in some embodiments, it is preferably not contained.

_Ta2O5 has the function of improving the refractive index and anti-devitrification performance, but compared with other components, _Ta2O5 is very expensive. From the perspective of practicality and _cost , its usage should be minimized. The content _{of Ta2O5} in the present invention is _0-5 %, preferably 0-2%, and in some embodiments, it is preferably not contained.

_Nb2O5 has the function of increasing the refractive index and dispersion of glass, and also has the function of improving _the anti-devitrification and chemical stability of glass. If its content exceeds 5%, the dispersion of glass increases, and it is difficult to achieve the optical properties of the glass of the present invention, and the devitrification resistance of glass deteriorates. Therefore, the content of _Nb2O5 ranges from 0 to 5 _% , preferably from 0 to 2%. In some embodiments, it is preferably not introduced.

TiO ₂ , WO ₃ , Ta ₂ O ₅ , and Nb ₂ O ₅ all have the function of increasing the refractive index, but their introduction will also cause a significant increase in glass dispersion, so the total value of TiO ₂ , WO ₃ , Ta ₂ O ₅ , and Nb ₂ O ₅ TiO ₂ +WO ₃ +Ta ₂ O ₅ +Nb ₂ O ₅ is limited to between 0 and 5%, preferably 0 to 2%, and in some embodiments, it is preferably not contained. In some embodiments, the value of TiO ₂ +WO ₃ +Ta ₂ O ₅ +Nb ₂ O ₅ may be 0, greater than 0, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, or 5%.

Li ₂ O is an alkali metal oxide. Its addition can reduce the high temperature viscosity of glass and make the production of glass easier. It is an essential component of the present invention. However, if its content exceeds 12%, the chemical stability and anti-crystallization performance of the glass will decrease. Therefore, the content of Li ₂ O in the present glass component is 2-12%, preferably 3-11%, and more preferably 4-10%. Na ₂ O and K ₂ O, which are also alkali metal oxides, can also reduce the high temperature viscosity of glass, but will cause a sharp decrease in chemical stability. Therefore, the content of Na ₂ O in the glass of the present invention is limited to 0-10%, preferably 0-5%, and in some embodiments, it is preferably not contained. The content of _{K 2} O is limited to 0-10%, preferably 0-5%, and in some embodiments, it is preferably not contained.

Both ZnO and Li ₂ O have the effect of reducing the glass transition temperature. The inventors have found that when the content of ZnO divided by 3 plus the content of Li ₂ O (ZnO/3+Li ₂ O) is within the range of 6-12%, the glass transition temperature can be reduced, so that the glass transition temperature can meet the design requirements. Therefore, in the present invention, the range of ZnO/3+Li ₂ O is 6-12%, preferably 6.5-11%, and more preferably 7-10%. In some embodiments, ZnO/3+Li ₂ O can be 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, 10.5%, 11%, 11.5%, 12%.

The introduction of SiO ₂ and Al ₂ O ₃ can improve the crystallization stability of glass, but will make the melting performance of glass worse. ZnO can play a role in fluxing, but it will also make the glass easy to crystallize. The inventors have devoted themselves to research and found that when the ratio of (SiO ₂ +Al ₂ O ₃ ) to ZnO (SiO ₂ +Al ₂ O ₃ )/ZnO is between 1.5 and 25, the relationship between chemical stability and melting performance can be well balanced, thereby obtaining excellent chemical stability and melting performance. Therefore, the range of (SiO ₂ +Al ₂ O ₃ )/ZnO is 1.5 to 25, preferably 1.6 to 22, and more preferably 1.7 to 20. In some embodiments, the value of (SiO2+ _{Al2O3 )} /ZnO may be 1.5, 1.6, 1.7, 2, 2.5, _3, 3.5, 4, 4.5, 5, 5.5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25.

One or more _{of Sb2O3} , _SnO2 , SnO and _CeO2 can be added as a clarifier. By adding a small amount of _Sb2O3 , _SnO2 and _{CeO2 ,} the clarification effect of the glass can be improved. However, when the content of _Sb2O3 exceeds 1 _% , the clarification performance of the glass tends to decrease. At the same time, its strong oxidizing effect promotes the deterioration of the forming _mold . Therefore, the amount of _Sb2O3 added in the present invention is 1% or less, preferably 0.5% or less. _SnO2 and SnO can also be added as a clarifier, but when their content exceeds 1%, the glass will be colored, or when the glass is heated, softened and molded again, Sn will become the starting point of crystal nucleation, resulting in a tendency of devitrification. Therefore, the contents of _SnO2 and SnO in the present invention are 1% or less, preferably 0.5% or less, and more preferably not introduced. The role and addition ratio of CeO ₂ are consistent with those of SnO ₂ , and its content is 1% or less, preferably 0.5% or less, and more preferably not introduced.

In some embodiments, As ₂ O ₃ , Cl compounds, Br compounds, etc. may also be used as clarifiers, with their contents being less than 1%, preferably less than 0.5%. However, considering factors such as environmental protection, it is preferred not to introduce As ₂ O ₃ .

[About ingredients that should not be contained]

Other components not mentioned above can be added as needed within the range that does not impair the glass properties of the present invention. However, transition metal components such as V, Cr, Mn, Fe, Co, Ni, Cu, Ag and Mo, even if contained in small amounts alone or in combination, will color the glass and produce absorption at specific wavelengths in the visible light region, thereby weakening the property of improving the visible light transmittance of the present invention. Therefore, it is preferred that the optical glass, especially for optical glass with required transmittance at wavelengths in the visible light region, actually contain them.

The cations of Pb, Th, Cd, Tl, Os, Be and Se have a tendency to be controlled in recent years as harmful chemical substances, and environmental protection measures are necessary not only in the manufacturing process of glass, but also in the processing process and the disposal after productization. Therefore, in the case of paying attention to the impact on the environment, it is preferred that they are not actually contained except for the inevitable mixing. Thus, the optical glass does not actually contain substances that pollute the environment. Therefore, even if no special environmental countermeasures are taken, the optical glass of the present invention can be manufactured, processed and discarded.

The "not introduced", "not containing" and "0" recorded in this article mean that the compound, molecule or element is not intentionally added as a raw material to the optical glass of the present invention; however, as raw materials and/or equipment for producing optical glass, there will be certain impurities or components that are not intentionally added, which will be contained in a small amount or trace amount in the final optical glass, and this situation is also within the scope of protection of the patent of this invention.

Next, the properties of the optical glass of the present invention will be described.

[Refractive Index and Abbe Number]

The refractive index (nd) and Abbe number (ν _d ) of optical glass are tested according to the method specified in GB/T 7962.1-2010.

The refractive index (nd) of the optical glass of the present invention is in the range of 1.55-1.65, preferably in the range of 1.57-1.63, and more preferably in the range of 1.58-1.61; the Abbe number (ν _d ) of the glass of the present invention is in the range of 56-65, preferably in the range of 57-64, and more preferably in the range of 59-62.

[Acid resistance stability D _A ]

The acid resistance stability ( _DA ) of optical glass is measured by the method specified in the GB/T17129 test standard.

The acid resistance stability (D _A ) of the optical glass of the present invention is 4 or more, preferably 3 or more.

[Transition temperature]

The optical glass transition temperature (T _g ) is measured using the method specified in the GB/T7962.20~2010 test standard.

The optical glass transition temperature (T _g ) of the present invention is not higher than 540°C, preferably not higher than 530°C, more preferably not higher than 520°C, and further preferably not higher than 515°C.

[Upper limit of crystallization temperature]

The crystallization temperature upper limit test method is: put the glass sample into a 10*10* ^150mm3 platinum crucible, and put the crucible into a temperature gradient furnace of 900-1200℃ for 4 hours, take it out of the furnace, cool it naturally, and then immediately observe whether there is crystallization on the surface and in the glass. The lowest temperature in the set temperature range corresponding to the area where no crystallization is confirmed is taken as the "crystallization temperature upper limit". It should be noted here that this test method is only valid for the crystallization temperature upper limit of 900-1200℃. When no crystallization is found on the entire surface and inside of the sample after heat preservation, it can be determined that the crystallization temperature upper limit of the sample is lower than 900℃.

Glass with a low upper limit of crystallization temperature has a lower risk of crystallization even when the molten glass is discharged at a relatively low temperature, thus reducing the risk of devitrification when the glass is formed from a molten state, and reducing the impact on the optical properties of the optical element using the glass. In addition, a low liquidus temperature can reduce the molding temperature of the glass, reduce the energy loss during the molding of the glass, and reduce the manufacturing cost of the glass.

The optical glass of the present invention has excellent crystallization stability and a low upper crystallization temperature limit (T _max ). The upper crystallization temperature limit (T _max ) of the optical glass of the present invention is preferably 1100°C, more preferably 1000°C, further preferably 900°C, and further preferably lower than 900°C.

Ⅱ. Glass preforms and optical elements

Next, the glass preform and the optical element of the present invention are described.

The glass preform and optical element of the present invention are both formed of the optical glass of the present invention. The glass preform of the present invention has the same optical properties and chemical properties as the optical glass; the optical element of the present invention also has the same optical properties and chemical properties as the optical glass, and can provide various optical elements such as lenses and prisms with high optical value at low cost.

Examples of the lens include various lenses having spherical or aspherical lens surfaces, such as a concave meniscus lens, a convex meniscus lens, a biconvex lens, a biconcave lens, a plano-convex lens, and a plano-concave lens.

In addition, prisms can be combined in the camera optical system to achieve a compact, wide-angle optical system by bending the light path in the desired direction.

[Optical Glass Example]

In the following, the embodiments listed in the table will describe the present invention in more detail for reference by other technicians. It should be noted that the glass component contents in embodiments 1 to 40 are expressed in weight percentages, and the protection scope of the present invention is not limited to the embodiments.

The optical glasses (Examples 1 to 40) shown in Tables 1 to 4 are prepared by weighing and mixing common raw materials for optical glass (such as oxides, hydroxides, carbonates, nitrates, etc.) according to the contents of the respective examples shown in Tables 1 to 4, placing the mixed raw materials in a platinum crucible, melting them at 1250°C to 1400°C for 2 to 5 hours, and obtaining a homogeneous molten glass without bubbles and undissolved matter after clarification, stirring and homogenization, and casting and annealing the molten glass in a mold.

For the components of Examples 1 to ₄₀ of the present invention, the _SiO2 / _B2O3 value is represented by A1; the BaO+SrO+CaO+MgO value is represented by A2; the _TiO2 + _WO3 + _Ta2O5 + _Nb2O5 value is represented by _A3 ; _{the ZnO/3+Li2O value} is represented by A4; and the ( _SiO2 + _Al2O3 )/ _ZnO value is represented by A5.

Table 1

Table 2

Table 3

Table 4

[Glass preform embodiment]

The optical glass obtained in Examples 1 to 40 is cut into predetermined sizes, and a release agent is evenly applied on the surface, and then heated, softened, and press-formed to produce preform blanks of various lenses and prisms such as concave meniscus lenses, convex meniscus lenses, biconvex lenses, biconcave lenses, plano-convex lenses, and plano-concave lenses. These blanks are then cleaned, ground, polished, and other processes to produce preforms.

[Optical Element Embodiment]

The glass preform is heated and pressed on a precision molding device 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. The surface of the obtained optical element can also be coated with an anti-reflection film.

The present invention is a heavy crown optical glass for precision molding with excellent chemical stability, with a refractive index of 1.55-1.65 and an Abbe number of 56-65, and preforms and optical elements formed by the glass, which can meet the needs of modern new optoelectronic products.

Claims (11)

1. Optical glassThe paint is characterized by comprising the following components in percentage by weight: siO 2 ₂ ：20～43％；B ₂ O ₃ ：20～50％；Al ₂ O ₃ ：0～10％；La ₂ O ₃ ：0～10％；BaO：10～30％；ZnO：2～15％；Li ₂ O：2～12％。

2. The optical glass according to claim 1, wherein the composition further comprises, in weight percent: gd (Gd) ₂ O ₃ :0 to 5 percent; and/or Y ₂ O ₃ :0 to 5 percent; and/or MgO:0 to 10 percent; and/or SrO:0 to 10 percent; and/or CaO:0 to 10 percent; and/or ZrO ₂ :0 to 10 percent; and/or TiO ₂ :0 to 5 percent; and/or WO ₃ :0 to 5 percent; and/or Ta ₂ O ₅ :0 to 5 percent; and/or Nb ₂ O ₅ :0 to 5 percent; and/or Na ₂ O:0 to 10 percent; and/or K ₂ O:0 to 10 percent; and/or Sb ₂ O ₃ ：0～1％。

3. Optical glass, characterized in that its composition, expressed in weight percentage, is represented by SiO ₂ ：20～43％；B ₂ O ₃ ：20～50％；Al ₂ O ₃ ：0～10％；La ₂ O ₃ ：0～10％；BaO：10～30％；ZnO：2～15％；Li ₂ O：2～12％；Gd ₂ O ₃ ：0～5％；Y ₂ O ₃ ：0～5％；MgO：0～10％；SrO：0～10％；CaO：0～10％；ZrO ₂ ：0～10％；TiO ₂ ：0～5％；WO ₃ ：0～5％；Ta ₂ O ₅ ：0～5％；Nb ₂ O ₅ ：0～5％；Na ₂ O：0～10％；K ₂ O：0～10％；Sb ₂ O ₃ :0 to 1 percent of the composition.

4. An optical glass according to any one of claims 1 to 3, wherein the composition is expressed in weight percent, wherein: siO 2 ₂ /B ₂ O ₃ :0.5 to 2.2, preferably SiO ₂ /B ₂ O ₃ :0.6 to 2, more preferably SiO ₂ /B ₂ O ₃ :0.7 to 1.8; and/or ZnO/3+ Li ₂ O is 6 to 12 percent; znO/3+ Li is preferable ₂ O is 6.5 to 11 percent, and ZnO/3+ Li is more preferable ₂ O is 7 to 10 percent; and/or (SiO) ₂ +Al ₂ O ₃ ) The ratio of/ZnO is 1.5 to 25, preferably (SiO) ₂ +Al ₂ O ₃ ) The content of/ZnO is 1.6 to 22, and more preferably (SiO) ₂ +Al ₂ O ₃ ) The ratio of/ZnO is 1.7-20.

5. An optical glass according to any one of claims 1 to 3, wherein the composition is expressed in weight percent, wherein: siO 2 ₂ :22 to 43%, preferably SiO ₂ :25 to 40 percent; and/or B ₂ O ₃ :25 to 45%, preferably B ₂ O ₃ :30 to 40 percent; and/or Al ₂ O ₃ :2 to 8%, preferably Al ₂ O ₃ :3 to 7 percent; and/or La ₂ O ₃ :0 to 8%, preferably La ₂ O ₃ :0 to 6 percent; and/or BaO:12 to 28%, preferably BaO:14 to 26 percent; and/or ZnO:3 to 14%, preferably ZnO:4 to 13 percent; and/or Li ₂ O:3 to 11%, preferably Li ₂ O:4 to 10 percent; and/or Gd ₂ O ₃ :0 to 3 percent; and/or Y ₂ O ₃ :0 to 3 percent; and/or MgO:0 to 5 percent; and/or SrO:0 to 5 percent; and/or CaO:0 to 8%, preferably CaO:0 to 6 percent; and/or ZrO ₂ :0 to 5 percent; and/or TiO ₂ :0 to 2 percent; and/or WO ₃ :0 to 2 percent; and/or Ta ₂ O ₅ :0 to 2 percent; and/or Nb ₂ O ₅ :0 to 2 percent; and/or Na ₂ O:0 to 5 percent; and/or K ₂ O：0～5％。

6. An optical glass according to any one of claims 1 to 3, wherein the composition is expressed in weight percent, wherein: mgO + CaO + SrO + BaO is 12 to 40%, preferably MgO + CaO + SrO + BaO is 13 to 35%, more preferably MgO + CaO + SrO + BaO is 14 to 30%; and/or TiO ₂ +WO ₃ +Ta ₂ O ₅ +Nb ₂ O ₅ Is 0 &5%, preferably TiO ₂ +WO ₃ +Ta ₂ O ₅ +Nb ₂ O ₅ Is 0 to 2 percent.

7. An optical glass according to any one of claims 1 to 3, wherein the refractive index n of the optical glass is _d Is in the range of 1.55 to 1.65, preferably 1.57 to 1.63, more preferably 1.58 to 1.61; abbe number v _d Is 56 to 65, preferably 57 to 64, more preferably 59 to 62.

8. An optical glass according to any one of claims 1 to 3, wherein the optical glass has a transition temperature T _g Not higher than 540 ℃, preferably not higher than 530 ℃, more preferably not higher than 520 ℃, and still more preferably not higher than 515 ℃; and/or an upper crystallization temperature limit T _max 1100 ℃, preferably 1000 ℃, more preferably 900 ℃, and still more preferably less than 900 ℃; and/or stability against acid action D _A Is 4 or more, preferably 3 or more.

9. A glass preform made of the optical glass according to any one of claims 1 to 8.

10. An optical element produced from the optical glass according to any one of claims 1 to 8 or the glass preform according to claim 9.

11. An optical device comprising the optical glass according to any one of claims 1 to 8 or the optical element according to claim 10.