CN109650716B

CN109650716B - Colorless optical glass and glass prefabricated member, element and instrument thereof

Info

Publication number: CN109650716B
Application number: CN201910058914.6A
Authority: CN
Inventors: 匡波
Original assignee: CDGM Glass Co Ltd
Current assignee: CDGM Glass Co Ltd
Priority date: 2019-01-22
Filing date: 2019-01-22
Publication date: 2021-12-07
Anticipated expiration: 2039-01-22
Also published as: CN109650716A

Abstract

The invention discloses colorless optical glass and a prefabricated member, an element and an instrument thereof, which solve the problem of overcoming the defect in the prior artClothes La₂O₃The influence on the properties such as refractive index, dispersion and crystallization upper limit temperature caused by the excessively high content of the glass needs to increase the production cost of the glass. The invention comprises the following components in percentage by weight: b is₂O₃ 25～45t％；La₂O₃ 30～50t％；Gd₂O₃ 0～10t％；Y₂O₃3-20 t%; wherein, the Gd₂O₃And La₂O₃The ratio of (A) to (B) is 0.01-0.3. The invention can improve the refractive index/reduce the dispersion and reduce Gd simultaneously through reasonable optimization of the composition and the proportion₂O₃And Ta₂O₅The usage amount of the glass reduces the cost, effectively ensures that the crystallization upper limit temperature of the glass is not increased, has better glass forming property, is not easy to generate glass bubbles in the melting process, and also ensures good optical performance and forming performance.

Description

Colorless optical glass and glass prefabricated member, element and instrument thereof

Technical Field

The invention relates to the field of glass, in particular to colorless optical glass and a prefabricated member, an element and an instrument thereof.

Background

There is a rapid trend toward higher integration and functional improvement in recent devices using optical systems, and there is a growing desire to reduce the weight and size of optical systems. To fulfill this desire, optical designs using aspherical lenses made of high-performance glass are becoming mainstream. Generally, such a glass is heated to a temperature allowable for molding and then molded by precision press molding, thereby producing an aspherical lens. In particular, although large-aperture lenses used recently are spherical lenses, these lenses are being replaced by aspherical lenses of larger aperture in order to further improve the functions. There is an increasing need for high performance glasses for use in the production of these lenses to have high refractive index and low dispersion characteristics. It is considered that each of them contains B₂O₃And La₂O₃The glass as a main component is a glass which has been used so far and satisfies these requirements and has high refractive index and low dispersion characteristics.

However, those glasses used so far have a problem that they generally have a high forming temperature. The high forming temperature causes the following problems:

the mold for high-precision mold pressing has the following performance requirements: can be processed with high surface accuracy and can be unchanged at the forming temperature. Therefore, the mold is generally made of a cemented carbide WC and is further coated with a metal as a separation film on the surface thereof for preventing the mold from adhering to the glass. However, even if the mold is coated with the separation film, resistance to repetition of cycles of the mold decreases with an increase in the molding temperature, and therefore, it is desirable to perform press molding at a lower temperature to ensure resistance to repetition of cycles of the mold.

In order to overcome the above-mentioned problems associated with high forming temperatures, various glasses known as optical glasses have been proposed in the prior art, which glasses comprise B as the main component₂O₃、La₂O₃And Li₂O, and at the same time, the glass has a low yield point. However, each of these glasses is designed with emphasis on chemical stability, resistance to heat devitrification and low press forming temperature characteristics, and is substantially free of more than 30% of rare earth elements such as La₂O₃. Thus, such glasses are susceptible to devitrification during high temperature forming processes, such as casting or billet forming.

La₂O₃The component is an essential component essential for increasing the refractive index of the glass and maintaining the light transmittance. It can be used to increase the Abbe number while increasing the refractive index of the glass. However, if the content is too large, for example, exceeds 38 wt%, the temperature coefficient of the relative refractive index tends to be large, the crystallization property tends to be deteriorated, and the chemical stability tends to be poor. Thus, in the prior art, the La content is conventionally high₂O₃In order to overcome the high La₂O₃The content of the auxiliary oxide is not limited, and other auxiliary oxides are usually added, such as a high-refractive low-dispersion optical glass with excellent devitrification resistance disclosed in CN201710970405.1, wherein high La is used₂O₃But Gd is increased in order to lower the upper limit temperature of crystallization₂O₃And Ta₂O₅Due to Ta₂O₅At lower levels, it is generally desirable to increase Gd₂O₃Due to Gd₂O₃And Ta₂O₅Both are relatively expensive, and therefore, it is required to obtain a glass having a relatively high refractive index, an Abbe number and a crystallization upper limit temperature, and the cost thereof is relatively high.

Disclosure of Invention

The invention aims to provide colorless optical glass, which solves the problem in the prior art that La is not available₂O₃The excessive content of the component (A) causes influence on properties such as refractive index, dispersion and crystallization upper limit temperatureThe production cost of the glass is increased; through reasonable optimization of composition and proportion, Gd can be reduced while the refractive index is improved/the dispersion is reduced₂O₃And Ta₂O₅The usage amount of the glass reduces the cost, ensures that the crystallization upper limit temperature of the glass is not increased, has better glass forming property, is not easy to generate glass bubbles in the melting process, and also ensures good optical performance and forming performance.

The invention is realized by the following technical scheme:

a colorless optical glass comprising, in wt%:

B₂O₃ 25～45％；

La₂O₃ 30～50％；

Gd₂O₃ 0～10％；

Y₂O₃ 3～20％；

wherein, the Gd₂O₃And La₂O₃The ratio of (A) to (B) is 0.01-0.3.

Still further, in wt%, the

Y₂O₃5-18%; and/or

Gd₂O₃0.5-8%; and/or

La₂O₃35-45%; and/or

B₂O₃28-40%; and/or

Gd₂O₃And La₂O₃The ratio of (A) to (B) is 0.02-0.25.

Further, in wt%, the

Y₂O₃9-15%; and/or

Gd₂O₃1-5%; and/or

La₂O₃38-43%; and/or

B₂O₃30-37%; and/or

Gd₂O₃And La₂O₃The ratio of (A) to (B) is 0.03-0.20.

Further, the composition also comprises the following components in percentage by weight:

SiO₂0 to 10 percent; and/or

ZrO₂0-8%; and/or

0-10% of ZnO; and/or

R₂0-8% of O; and/or

Sb₂O₃0 to 1 percent; and/or

RO 0-5%; and/or

TiO₂+Nb₂O₅+WO₃ 0～5％；

Wherein R is₂O is Li₂O、Na₂O、K₂One or more of O, and RO is one or more of MgO, CaO, SrO and BaO.

Further, in wt%, the

SiO₂1-8%, preferably 2-6%; and/or

ZrO₂0 to 5%, preferably 0 to 2%; and/or

1-8% of ZnO, preferably 2-6%; and/or

R₂0.5-5% of O, preferably 0.5-3%; and/or

Sb₂O₃0 to 0.5%, preferably 0 to 0.1%; and/or

RO is 0-3%, preferably not contained; and/or

TiO₂+Nb₂O₅+WO₃0 to 3%, preferably none;

Further, the ZnO and B₂O₃The ratio of (A) to (B) is 0-0.35; preferably 0.03 to 0.30; more preferably 0.05 to 0.20.

Further, the SiO₂And B₂O₃The ratio of (A) to (B) is 0.02-0.35; preferably 0.05 to 0.30; more preferably 0.05 to 0.20.

Further, the Li₂O and Gd₂O₃The ratio of (A) to (B) is more than 0.1; preferably 0.20 to 5.00; more preferably 0.30 to 2.00.

Further, the Li₂O and Y₂O₃The ratio of (A) to (B) is 0.02-2.00; preferably 0.03 to 1.00; more preferably 0.05 to 0.50, and still more preferably 0.05 to 0.25.

Further, Y₂O₃/(La₂O₃+B₂O₃) The value of (A) is 0.05 to 0.35; preferably 0.10 to 0.30; more preferably 0.14 to 0.25.

Further, Y₂O₃/(La₂O₃+Gd₂O₃) The value of (b) is 0.10 to 0.60, preferably 0.15 to 0.50, and more preferably 0.2 to 0.40.

Further, does not contain Ta₂O₅And/or Al₂O₃。

Further, the material also comprises 0-10% of XO, wherein the XO is Yb₂O₃、P₂O₅、GeO₂、Ga₂O₃、SnO₂One or more of; XO is preferably 0 to 5%.

Further, the upper limit crystallization temperature of the glass is 1100 ℃ or lower, preferably 1090 ℃ or lower, and more preferably 1080 ℃ or lower; the water resistance stability of the glass is 2 or more, preferably 1.

Further, lambda of the glass₈₀390nm or less, preferably 380nm or less, and more preferably 370nm or less; lambda of glass₅300nm or less, preferably 290nm or less, and more preferably 280nm or less; the glass transition temperature is 630 ℃ or lower, preferably 620 ℃ or lower; the density of the glass is 4.50g/cm³Hereinafter, it is preferably 4.3g/cm³Hereinafter, more preferably 4.2g/cm³The following; the refractive index nd of the glass is 1.70-1.75, preferably 1.71-1.74, and more preferably 1.72-1.74; abbe number v_d51 to 57, preferably 52 to 56, and more preferably 53 to 55.

The invention also includes glass preforms, optical elements, optical instruments. The glass prefabricated member is made of the optical glass, the optical element is made of the optical glass or the glass prefabricated member, and the optical instrument is made of the optical element.

Compared with the prior art, the invention has the following advantages and beneficial effects:

1. the La is simultaneously added on the basis of the technology of conventional dosage through the optimization of components and proportion₂O₃、Y₂O₃Content of Gd is reduced₂O₃In conventional amounts, without using expensive Ta₂O₅Effectively reduce the cost and contract to use Gd₂O₃And La₂O₃The ratio of (A) to (B) is adjusted within the range of 0.01-0.30, so that the crystallization upper limit temperature of the glass is not increased, the glass forming property is better, glass bubbles are not easy to generate in the melting process, and good optical performance and forming performance are also ensured;

2. the invention can also effectively ensure the excellence of the properties of low softening point, easy mould pressing, crystallization upper limit temperature, chemical stability and the like.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to examples, and the exemplary embodiments and descriptions thereof are only used for explaining the present invention and are not used as limitations of the present invention.

The composition ranges of the components of the optical glass of the present invention will be described below. In the present specification, the contents of the respective components are all expressed in terms of weight percent (wt%) relative to the total amount of glass matter converted into the composition of oxides, if not specifically stated. Here, the "composition converted to oxides" means that when oxides, complex salts, hydroxides, and the like used as raw materials of the optical glass composition component of the present invention are decomposed in the melt and converted to oxides, the total amount of the oxides is 100%.

Unless otherwise indicated in a specific context, numerical ranges set forth herein include upper and lower values, and "above" and "below" include endpoints, all integers and fractions within the range, and are not limited to the specific values listed in the defined range. As used herein, "and/or" is inclusive, e.g., "A and/or B," and means A alone, B alone, or both A and B.

B₂O₃Has the function of fluxing if B₂O₃If the content is too small, the devitrification resistance of the glass is not satisfactory, but if B is contained in the glass₂O₃If the content is too large, the refractive index is low, the chemical stability is poor, and the requirement is not satisfied. In the invention B₂O₃The content is set to be 25-45%, and preferably 28-40%; more preferably 30 to 37%.

La₂O₃The component is an essential component essential for increasing the refractive index of the glass and maintaining the light transmittance. Further, it is also effective for increasing the Abbe number. If the content is too small, it is difficult to sufficiently obtain the above-mentioned effects, and if the content is too large, for example, exceeds 50%, the temperature coefficient of the relative refractive index tends to be large, the crystallization performance tends to be deteriorated, and the chemical stability tends to be poor. La in the invention₂O₃The content is set to be 30-50%, preferably 35-45%; more preferably 38 to 43%.

La₂O₃、Gd₂O₃、Y₂O₃And Yb₂O₃Among them, La is the component having the greatest effect of increasing the refractive index of the glass and maintaining the stability of the glass₂O₃. However, if only La is used for the optical glass of the present invention₂O₃It is difficult to ensure sufficient glass stability. Therefore, La is used in the present invention₂O₃The most amount of the components is introduced, and La is added₂O₃And Y₂O₃Coexistence; or preferably La₂O₃、Gd₂O₃And Y₂O₃Coexistence; however, in general, the more rare earth oxides are introduced, the more the glass is easy to crystallize, and the difficulty is brought to the mass production process; thus Y in the invention₂O₃The content is set to 3-20%, preferably5-18%; more preferably 9-15%; gd (Gd)₂O₃The content is set to be 0-10%, preferably 0.5-8%; more preferably 1 to 5%.

SiO₂Has the functions of adjusting the viscosity of the glass and the devitrification resistance if SiO₂An excessive content of the component (B) may lower the meltability of the glass and increase the softening temperature, and if SiO is used₂If the content is too small, the purpose of adjusting the viscosity of the glass and suppressing the tendency to crystallize may not be achieved. SiO in the invention₂The content is set to 0-10%, preferably 1-8%, and more preferably 2-6%.

ZrO₂When the amount of the component (A) is small, the glass devitrification temperature can be lowered to inhibit crystallization, and therefore, the chemical stability can be improved. If the content is too small, it is difficult to sufficiently obtain the above-mentioned effects, and if the content is too large, crystalline substances are likely to be generated in the glass. ZrO in the invention₂The content is set to 0 to 8%, preferably 0 to 5%, and more preferably 0 to 2%.

The ZnO component is effective for lowering the devitrification temperature and lowering the Tg, but if the content thereof is too large, the chemical stability is liable to deteriorate. In the invention, the ZnO content is set to be 0-10%, preferably 1-8%, and more preferably 2-6%.

R₂O comprises Li₂O、Na₂O、K₂And O, which is a component having a large effect of reducing the temperature coefficient of the relative refractive index, and also has the effects of lowering the devitrification temperature and improving the chemical stability. If the content is too small, the effect described above is insufficient, and if the content is too large, the glass tends to exhibit an opacifying phenomenon, which is disadvantageous in removing glass streaks. In the invention, R₂The content of O is set to 0 to 8%, preferably 0.5 to 5%, more preferably 0.5 to 3%, and further, when R is₂O is preferably Li₂The effects of increasing the meltability and lowering the Tg are more pronounced with O.

Sb₂O₃The component (B) has a defoaming effect in the glass melting step. Sb in the invention₂O₃The content is set to 0 to 1%, preferably 0 to 0.5%, and more preferably 0 to E0.1％。

The MgO component is an arbitrary component that lowers the melting temperature, but if the content thereof exceeds 5%, the stability against devitrification deteriorates, and the tendency to phase separation tends to increase. The CaO component is an optional component effective for lowering the devitrification temperature, lowering Tg and specific gravity, as in the ZnO component, but if the content thereof is too large, devitrification resistance is liable to deteriorate. The SrO component is an arbitrary component for lowering the devitrification temperature and adjusting the refractive index, but if the content thereof is too large, the devitrification resistance is liable to deteriorate. The BaO component is an optional component effective for lowering the devitrification temperature and adjusting the optical constant, but if the content thereof is too large, the devitrification resistance is liable to deteriorate. In the present invention, the RO content is set to 0 to 5%, preferably 0 to 3%, and more preferably not contained.

With appropriate introduction of a certain amount of TiO₂、Nb₂O₅、WO₃The total content is 0 to 5%, preferably 0 to 3%, and more preferably not contained, because the content of the glass dispersion increases when the content exceeds 5%, the glass dispersion increases, the glass coloring tendency increases, and the transmittance decreases.

Yb₂O₃Is an effective component for increasing the refractive index, but if the content is more than 10%, the melting temperature will be increased and the glass stability will be lowered. Thus, Yb of the invention₂O₃The content of (b) is 0 to 10%, preferably 0 to 5%, and more preferably no incorporation.

P₂O₅Can participate in the network structure to play a certain role, but when the introduction amount is more than 10 percent, the glass stability is reduced, the crystallization tendency is increased, and therefore, the P of the invention₂O₅The content of (b) is 0 to 10%, preferably 0 to 5%, and more preferably not introduced.

GeO₂It is advantageous to lower the melting temperature of the glass and improve the glass stability, but in view of cost, it is preferable for those skilled in the art to use GeO in an amount as low as possible₂Thus, GeO of the invention₂The content of (b) is 0 to 10%, preferably 0 to 5%, and more preferably not introduced.

Ga₂O₃The glass stability can be suitably improved, but if the content is too high, Tg may be increased, and therefore, Ga in the present invention₂O₃The content of (b) is selected from 0 to 10%, preferably 0 to 5%, and more preferably not incorporated.

SnO₂It may be added as a fining agent, but when the content exceeds 10%, the glass is colored, or when the glass is heated, softened, and subjected to secondary molding such as press molding, Sn becomes a starting point of nucleation, and tends to devitrify. Thus SnO₂The content of (b) is 0 to 10%, preferably 0 to 5%, and more preferably no incorporation.

Other components not mentioned above, such as Lu, can be added in small amounts as required within the range not impairing the characteristics of the glass of the present invention³⁺、Ce⁴⁺And the like. But V⁵⁺、Cr³⁺、Mn²⁺、Fe³⁺、Co²⁺、Ni²⁺、Cu²⁺、Ag⁺And Mo⁶⁺The transition metal oxide component, if contained in a small amount alone or in combination, is preferably not substantially contained in the optical glass, which is required to have a transmittance at a wavelength in the visible light region, because the glass is colored and absorbs at a specific wavelength in the visible light region, thereby reducing the property of the present invention to improve the visible light transmittance.

In recent years, compounds of Pb, As, Th, Cd, Tl, Os, Be, and Se tend to Be used As harmful chemical substances under control, and measures for protecting the environment are required not only in the glass production process but also in the processing process and disposal after commercialization. Therefore, when importance is attached to the influence on the environment, it is preferable that these components are not substantially contained except for inevitable mixing. Thereby, the optical glass becomes practically free from substances contaminating the environment. Therefore, the optical glass of the present invention can be manufactured, processed, and discarded without taking special measures for environmental countermeasures.

The term "not containing", "not introducing" or "0%" as used herein means that the compound, molecule or element is not intentionally added as a raw material to the glass of the present invention; however, it is also within the scope of the present invention that certain impurities or components, which are not intentionally added, may be present as raw materials and/or equipment for producing the glass, and may be present in small or trace amounts in the final glass.

The La is simultaneously added on the basis of the technology of conventional dosage through the optimization of components and proportion₂O₃、Y₂O₃Content of Gd is reduced₂O₃In conventional amounts, and without the use of costly Ta₂O₅And the cost is effectively reduced. Meanwhile, the invention enables the components to be optimally matched by further adjusting the component proportion so as to improve the overall performance of the glass.

By convention Y in the present invention₂O₃/(La₂O₃+Gd₂O₃) A value of (a) effective to overcome high La₂O₃、Y₂O₃The defect caused by the content effectively improves the devitrification resistance, and can effectively ensure the excellence of the performance such as the crystallization upper limit temperature, the chemical stability and the like, and when the ratio exceeds 0.60, the crystallization upper limit temperature of the glass is increased, the chemical stability is deteriorated, and the coloring tendency is increased. Thus, Y₂O₃/(La₂O₃+Gd₂O₃) The value of (A) is set to 0.10 to 0.60, preferably 0.15 to 0.50; more preferably 0.2 to 0.40. The effects of the present invention can be further verified by comparing examples with comparative examples.

In the present invention, ZnO and B are provided₂O₃Ratio of (ZnO/B)₂O₃Can further reduce the glass transition temperature Tg, increase the transmittance and reduce the degree of coloration, when ZnO/B is used₂O₃When the ratio exceeds 0.35, the devitrification resistance and chemical stability of the glass are rather deteriorated, and therefore, in some embodiments of the present invention containing ZnO, the ratio is set to 0 to 0.35, preferably 0.03 to 0.30, and more preferably 0.05 to 0.20.

By adjusting SiO₂And B₂O₃The proportion of the components can effectively improve the chemical stability of the glass and the stability of the formed glassQualitative and obvious effect. When SiO is present₂/B₂O₃When the ratio is less than 0.02 and exceeds 0.35, the glass forming stability of the glass is lowered and the chemical stability is lowered. Thus, some of the present invention contain SiO₂In the embodiment (1), SiO₂/B₂O₃The ratio is set to be 0.02-0.35, preferably 0.05-0.30, and more preferably 0.05-0.20.

In some containing Li₂O and Gd₂O₃In the embodiment of (1), when Li₂O and Gd₂O₃When the ratio of (A) to (B) is 0.1 or less, the devitrification resistance and chemical stability of the glass are lowered. Thus, Li in the present invention₂O and Gd₂O₃The ratio of (A) to (B) is set to 0.1 or more, preferably 0.20 to 5.00, more preferably 0.30 to 2.00. Through the setting of the conditions, the glass transition temperature can be effectively reduced, simultaneously, the glass transmittance is effectively improved, the degree of coloration is reduced, and the lambda value of the glass is adjusted₈₀Controlled below 390nm, lambda₅Controlled below 300 nm.

In some containing Li₂O and Y₂O₃In an embodiment of (1), the Li₂O and Y₂O₃Ratio of (A) to (B) Li₂O/Y₂O₃Is 0.02 to 2.00, preferably 0.03 to 1.00, more preferably 0.05 to 0.50, and most preferably 0.05 to 0.25. When Li is present₂O/Y₂O₃Below 0.02, the glass transition temperature rises, the specific gravity of the glass increases, and when Li is used₂O/Y₂O₃Above 2.0, the glass cost increases and the devitrification resistance of the glass deteriorates, so that the glass transition temperature can be effectively lowered and the density can be effectively lowered by the setting of the above range.

To achieve excellent optical performance, Y is optimized₂O₃/(La₂O₃+B₂O₃) When the ratio of (b) exceeds 0.35, the crystallization upper limit temperature of the glass becomes high, the chemical stability becomes poor, and the coloring tendency becomes high. Thus, Y is₂O₃/(La₂O₃+B₂O₃) The ratio of (A) to (B) is set to 0.05 to 0.35, preferably 0.10 to 0.30, more preferably 0.05 to 0.35Preferably 0.14 to 0.25.

In the present invention, Gd is₂O₃And La₂O₃The ratio of (A) to (B) is adjusted within the range of 0.01-0.30, so that the crystallization upper limit temperature of the glass is not increased, the glass forming property is better, glass bubbles are not easy to generate in the melting process, and good optical performance, forming performance and the like are also ensured. When the ratio exceeds 0.3, the refractive index is increased to some extent, but the cost is increased and the crystallization upper limit temperature is increased, so that Gd is preferable in the present invention₂O₃/La₂O₃0.02 to 0.25; more preferably, Gd₂O₃/La₂O₃0.03 to 0.20.

Examples

The colorless optical glass has the specific compositions and proportions in wt% as shown in tables 1-4.

TABLE 1

TABLE 2

TABLE 3

TABLE 4

In order to obtain glasses having compositions shown in tables 1 to 4, raw materials (carbonate, nitrate, hydroxide, oxide, boric acid, etc.) corresponding to optical glass components are weighed in proportion, mixed sufficiently to obtain a blended raw material, the blended raw material is put into a platinum crucible, heated to 1200 to 1400 ℃, melted, stirred, clarified to form uniform molten glass, the molten glass is appropriately cooled, poured into a preheated mold, kept at 550 to 750 ℃ for 2 to 4 hours, and then slowly cooled to obtain the optical glass. The characteristics of each glass were measured for the glass products produced in the above examples by the following measurement methods, and the measurement results are shown in tables 5 to 8. Wherein each measurement method is as follows:

density (ρ): testing according to GB/T7962.20-2010.

Refractive index (nd) and abbe number (vd): testing according to GB/T7962.1-2010.

Transition temperature (Tg): testing according to GB/T7962.16-2010.

Coloring of glass:

coloring degree (. lamda.) for short-wave transmission spectral characteristics of the glass of the present invention₈₀/λ₅) And (4) showing. Lambda [ alpha ]₈₀Refers to the wavelength, lambda, corresponding to a glass having a transmittance of 80%₅Refers to the wavelength corresponding to the glass transmittance of 5%, wherein₈₀Was measured using a glass having a thickness of 10. + -. 0.1mm with two opposing planes parallel to each other and optically polished, measuring the spectral transmittance in the wavelength region from 280nm to 700nm and showing a wavelength of transmittance of 80%. The spectral transmittance or transmittance is the intensity I of light incident perpendicularly to the surface of the glass_inOf (2) a lightIntensity I emitted through the glass and from a plane_outIn the case of light of (1) through (I)_out/I_inThe quantity expressed and also the transmission of the surface reflection losses on the above-mentioned surface of the glass. The higher the refractive index of the glass, the greater the surface reflection loss.

The spectral transmittance was measured using a glass sample having a thickness of 10. + -. 0.1mm with two optically polished planes opposed to each other, and calculated from the result thereof.

Upper limit temperature of crystallization:

measuring the crystallization performance of the glass by adopting a gradient temperature furnace method, manufacturing the glass into a sample of 180 x 10mm, polishing the side surface, putting the sample into a furnace with a temperature gradient (5 ℃/cm), heating to 1200 ℃, keeping the temperature for 4 hours, taking out the sample, naturally cooling to room temperature, observing the crystallization condition of the glass under a microscope, wherein the highest temperature corresponding to the occurrence of crystals of the glass is the crystallization upper limit temperature of the glass.

Stability to Water action (powder method) D_W: test method according to GB/T17129.

The test results of this example are shown in tables 5 to 8.

TABLE 5

TABLE 6

TABLE 7

TABLE 8

	31	32	Comparative example 1	Comparative example 2	Comparison 3	Comparative example 4
							nd	1.7412	1.7263	1.8421	1.8531	1.7822	1.7312
vd	56.41	54.91	44.32	45.82	50.57	54.44
							Tg(℃)	612	621	610	600	580	680
λ₈₀(nm)	384	365	385	380	387	385
							λ₅(nm)	291	267	310	305	313	250
ρ(g/cm³)	4.21	4.16	4.21	4.33	4.31	4.03
							D_W	Class 2	Class 1	Class 2	Class 2	Class 2	Class 2
Upper limit temperature of crystallization (. degree.C.)	1095	1080	1250	1250	1210	1020

The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are merely exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.

The glass preform, the optical element and the optical instrument of the present invention are described as follows:

the glass preform of the present invention and the optical element are each formed of the above-described optical glass of the present invention.

The glass preform of the present invention is made of the optical glass of the present invention, has a high refractive index and low dispersion characteristics, and is useful in various optical elements and optical designs. In particular, it is preferable to manufacture optical elements such as lenses, prisms, and mirrors from the glass of the present invention by means of precision press molding or the like. It should be noted that the features and advantages described above for glass apply equally to the glass preform and are not described in detail here.

The optical element of the present invention is made using the glass or glass preform of the present invention. Thus, the optical element of the present invention has high-refraction low-dispersion characteristics, and can provide various optical elements such as lenses and prisms having excellent performance. For example, the optical element of the present invention may be a spherical lens, an aspherical lens, various lenses such as a microlens, a diffraction grating, a lens with a diffraction grating, a lens array, a prism, or the like. In addition, an optical thin film such as an antireflection film, a total reflection film, a partial reflection film, or a film having spectroscopic characteristics may be provided on the optical element as necessary. When the optical element is a lens, the lens includes, but is not limited to, various lenses such as a concave meniscus lens, a convex meniscus lens, a double convex lens, a double concave lens, a plano-convex lens, and a plano-concave lens, each of which has a spherical or aspherical lens surface. Further, since the prism has a relatively high refractive index, by combining the prism with an imaging optical system and bending the optical path to direct the prism in a desired direction, a compact and wide-angle optical system can be realized.

It should be noted that the features and advantages described above for glass and glass preforms apply equally to the optical element and are not described in detail here.

The optical element formed by the optical glass can be used for manufacturing optical instruments such as photographic equipment, camera equipment, display equipment, monitoring equipment and the like. By using the optical element having excellent performance in the optical instrument, the customer experience of the optical instrument can be improved. It should be noted that the features and advantages described above for the optical element apply equally to the optical instrument and are not described in detail here.

Claims

1. A colorless optical glass comprising, in wt%:

wherein, the Gd₂O₃And La₂O₃The ratio of (A) to (B) is 0.03-0.20;

Y₂O₃/(La₂O₃+Gd₂O₃) The ratio of (A) to (B) is 0.2-0.40;

the upper limit temperature of crystallization of the glass is lower than 1080 ℃; lambda of glass₈₀A glass lambda of 390nm or less₅300nm or less, and a glass transition temperature of 625 ℃ or less;

and does not contain Nb₂O₅。

2. A colorless optical glass according to claim 1, further comprising in wt%:

3. An optical glass as defined in claim 2, characterised in that said glass is characterised in that it is present in wt.%

4. An optical glass as claimed in claim 3, characterized in that, in wt.%, the glass is

5. A colorless optical glass according to claim 2 or 3, wherein said ZnO and B are₂O₃The ratio of (A) to (B) is 0 to 0.35.

6. A colorless optical glass according to claim 5, wherein said ZnO and B are₂O₃The ratio of (A) to (B) is 0.03-0.30.

7. According to claim6 the colorless optical glass is characterized in that ZnO and B are₂O₃The ratio of (A) to (B) is 0.05-0.20.

8. A colorless optical glass according to claim 2 or 3, wherein said SiO is₂And B₂O₃The ratio of (A) to (B) is 0.02-0.35.

9. A colorless optical glass according to claim 8, wherein the SiO is₂And B₂O₃The ratio of (A) to (B) is 0.05-0.30.

10. A colorless optical glass according to claim 9, wherein the SiO is present in a coating solution₂And B₂O₃The ratio of (A) to (B) is 0.05-0.20.

11. A colorless optical glass according to claim 2 or 3, wherein said Li is₂O and Gd₂O₃The ratio of (A) to (B) is 0.1 or more.

12. A colorless optical glass according to claim 11, wherein the Li is present₂O and Gd₂O₃The ratio of (A) to (B) is 0.20 to 5.00.

13. A colorless optical glass according to claim 12, wherein the Li is present₂O and Gd₂O₃The ratio of (A) to (B) is 0.30 to 2.00.

14. A colorless optical glass according to claim 2 or 3, wherein said Li is₂O and Y₂O₃The ratio of (A) to (B) is 0.02-2.00.

15. A colorless optical glass according to claim 14, wherein the Li is present₂O and Y₂O₃The ratio of (A) to (B) is 0.03-1.00.

16. A colorless optical glass according to claim 15, wherein the Li is present₂O and Y₂O₃The ratio of (A) to (B) is 0.05-0.50.

17. A colorless optical glass according to claim 16, wherein the Li is present₂O and Y₂O₃The ratio of (A) to (B) is 0.05-0.25.

18. A colorless optical glass according to any one of claims 1 to 3, wherein Y is₂O₃/(La₂O₃+B₂O₃) The value of (A) is 0.05 to 0.35.

19. A colorless optical glass according to claim 18, wherein Y is₂O₃/(La₂O₃+B₂O₃) The value of (A) is 0.10 to 0.30.

20. A colorless optical glass according to claim 19, wherein Y is₂O₃/(La₂O₃+B₂O₃) The value of (b) is 0.14 to 0.25.

21. A colorless optical glass according to any one of claims 1 to 3, characterized in that it does not contain Ta₂O₅And/or Al₂O₃。

22. The colorless optical glass according to any one of claims 1 to 3, further comprising 0 to 10% of XO, wherein XO is Yb₂O₃、P₂O₅、GeO₂、Ga₂O₃、SnO₂One or more of (a).

23. The colorless optical glass of claim 22, wherein XO is 0-5%.

24. A colorless optical glass according to any one of claims 1 to 3, wherein the water resistance stability of the glass is 2 or more types.

25. A colorless optical glass according to claim 24, wherein the glass has a water stability of class 1.

26. A colorless optical glass according to any one of claims 1 to 3, wherein λ of the glass is₈₀Is 380nm or less; lambda of glass₅Is less than 290 nm; the glass transition temperature is below 620 ℃; the density of the glass is 4.50g/cm³The following; the refractive index nd of the glass is 1.70-1.75; abbe number v_d51 to 57.

27. A colorless optical glass according to claim 26 wherein λ of the glass is₈₀Is below 370 nm; lambda of glass₅Below 280 nm; the density of the glass is 4.3g/cm³The following; the refractive index nd of the glass is 1.71-1.74; abbe number v_dIs 52 to 56.

28. A colorless optical glass according to claim 27, wherein the glass has a density of 4.2g/cm³The following; the refractive index nd of the glass is 1.72-1.74; abbe number v_dIs 53 to 55.

29. A glass preform made of the colorless optical glass according to any one of claims 1 to 28.

30. An optical element made of the colorless optical glass according to any one of claims 1 to 28 or the glass preform according to claim 29.

31. An optical device made using the optical element of claim 30.