CN109205616B

CN109205616B - Optical glass, glass preform, optical element and optical instrument

Info

Publication number: CN109205616B
Application number: CN201811391994.9A
Authority: CN
Inventors: 毛露路; 匡波; 吴德林; 周佺佺
Original assignee: CDGM Glass Co Ltd
Current assignee: CDGM Glass Co Ltd
Priority date: 2018-11-21
Filing date: 2018-11-21
Publication date: 2021-06-25
Anticipated expiration: 2038-11-21
Also published as: CN109205616A; TW202019846A; JP7250130B2; WO2020103607A1; TWI798501B; JP2022509146A

Abstract

The invention provides an optical glass with medium refractive index and low temperature coefficient of refractive index, which comprises SiO₂、B₂O₃、La₂O₃RO and Rn₂An optical glass of O, wherein RO is one or more of MgO, CaO, SrO and BaO, Rn₂O is Li₂O、K₂O and Na₂And one or more than one of O, wherein the refractive index of the optical glass is 1.65-1.73, the Abbe number is 47-55, and the optical glass has a low temperature coefficient of refractive index, excellent anti-crystallization performance and excellent chemical stability.

Description

Optical glass, glass preform, optical element and optical instrument

Technical Field

The invention relates to optical glass, in particular to lanthanum-containing optical glass with a refractive index of 1.65-1.73 and an Abbe number of 47-55, and a glass prefabricated member, an optical element and an optical instrument made of the optical glass.

Background

In the prior art, glass with a refractive index of 1.65-1.73 and an Abbe number of 47-55 belongs to medium refractive index glass, and is widely applied to various lenses. In recent years, vehicle-mounted lens devices have been developed vigorously, and compared with general photography and other applications, the quality of the vehicle-mounted lens is related to safety, so that the vehicle-mounted lens emphasizes the reliability of the device, and particularly, the vehicle-mounted lens is exposed outside a vehicle body and needs to bear severe working environments, such as a reversing camera, a front-view camera, a rearview mirror auxiliary camera and the like.

The principle of designing a vehicle-mounted lens meeting the severe working environment is that the structure is as simple as possible, and the more complex the structure is, the worse the reliability is. Therefore, in order to meet the design requirement of long service life (more than ten years) of the vehicle-mounted lens suitable for severe working environment, the optical design generally adopts the design of a fixed-focus lens, the number of lenses of the fixed-focus lens is less than that of the zoom lens, and meanwhile, a zooming driving structure is not arranged, so that the reliability is greatly improved compared with that of the zoom lens.

However, although the prime lens has excellent reliability, it is applied to a vehicle, and it is very difficult to correct the temperature drift of the lens. The temperature drift of the lens means that when the temperature changes dramatically, for example, day and night temperature difference in desert area reaches 60 ℃, under the scene of very large temperature difference such as automobile driving from tropical zone to cold zone, the focal length of the lens changes, thereby causing imaging blur. For automobiles, safety is the first place, and therefore, a vehicle-mounted camera needs to keep clear imaging under the condition of rapid temperature change.

For optical designs, more different types of lens combinations and zoom systems can be used to address the temperature drift problem. However, due to the reliability requirement of the vehicle-mounted system, the temperature drift problem needs to be solved on the fixed-focus imaging system with few lenses (even 3 lenses), so that the development of optical glass with specific temperature refractive index is required, and the development of the times puts forward a new subject for optical design and optical material research.

The prior art optical glass with a refractive index of 1.65-1.73 and an Abbe number of 47-55 has a refractive index temperature coefficient value, namely d-line dn/dt relative (10), in the range of 20-40 DEG C^-6/deg.C) is substantially 1.0-3.0 (10 ℃)^-6/° c) (see table 1 below). The above temperature drift problem can be effectively addressed in the design if lanthanum crown glasses with temperature coefficients of refractive index below 0, and even below-1.0, and at super-optic levels can be developed.

Table 1: a temperature coefficient of refractive index of the glass having a partial refractive index of 1.65 to 1.73 and an Abbe number of 47 to 55

Serial number	nd	ν_d	D line dn/dt relative (10) within 20-40 DEG C^-6/℃)
				Example 1	1.72916	54.70	2.8
Example 2	1.69350	50.80	2.3
				Example 3	1.66461	54.61	1.9

However, if the temperature coefficient of the refractive index of the lanthanum crown glass with the refractive index and the abbe number is required to be lower than 0, the composition design is different from the conventional design, and the problems of poor devitrification resistance of the glass, difficult elimination of streak bubbles and the like are generally caused in the production.

If the anti-crystallization capacity of the glass is poor, the production difficulty of the glass blank is increased, so that the yield is reduced, and even normal production cannot be realized in severe cases; secondly, crystal precipitation is easy to generate in the secondary compression process, so that the yield is reduced, and even secondary compression can not be carried out. For the glass material applied in the vehicle-mounted field, if the production yield of the glass is low and the glass cannot be manufactured by adopting the secondary pressing method but the cold working method, the cost will be increased to cause the unacceptable.

Disclosure of Invention

The invention aims to provide optical glass with medium refractive index and low temperature coefficient of refractive index.

The technical scheme adopted by the invention for solving the technical problem is as follows:

(1) optical glass, the composition of which comprises SiO₂、B₂O₃、La₂O₃RO and Rn₂O, wherein R0 is one or more of MgO, CaO, SrO and BaO, Rn₂0 is Li₂O、K₂O and Na₂One or more than one of O, the refractive index of the glass is 1.65-1.73, the Abbe number is 47-55, and the temperature coefficient of the refractive index is less than or equal to 0.

(2) The optical glass according to (1), whose composition is expressed in weight percentComprising: SiO 2₂：4～20％、B₂O₃：10～30％、La₂O₃：10～35％、BaO：10～40％、SrO：0～15％、CaO：0～10％、MgO：0～5％、Li₂O：0～5％、K₂O：0～6％、Na₂O：0～8％、Gd₂O₃：0～8％、Y₂O₃：0～5％、ZrO₂：0～3％、Al₂O₃：0～3％、TiO₂：0～3％、Nb₂O₅：0～5％、WO₃: 0-2%, ZnO: 0-5% of a clarifying agent: 0 to 2 percent.

(3) Optical glass having a composition, expressed in weight percent, comprising: SiO 2₂：4～20％、B₂O₃：10～30％、La₂O₃：10～35％、BaO：10～40％、SrO：0～15％。

(4) The optical glass according to (3), further comprising: CaO: 0-10%, MgO: 0 to 5% of Li₂O：0～5％、K₂O：0～6％、Na₂O：0～8％、Gd₂O₃：0～8％、Y₂O₃：0～5％、ZrO₂：0～3％、Al₂O₃：0～3％、TiO₂：0～3％、Nb₂O₅：0～5％、WO₃: 0-2%, ZnO: 0-5% of a clarifying agent: 0 to 2 percent.

(5) Optical glass having a composition expressed in weight percent of SiO₂：4～20％、B₂O₃：10～30％、La₂O₃：10～35％、BaO：10～40％、SrO：0～15％、CaO：0～10％、MgO：0～5％、Rn₂0：0～8％、Gd₂O₃：0～8％、Y₂O₃：0～5％、ZrO₂：0～3％、Al₂O₃：0～3％、TiO₂：0～3％、Nb₂O₅：0～5％、WO₃: 0-2%, ZnO: 0 to 5%, wherein Rn₂0 is Li₂O、K₂O、Na₂One or more than one of O.

(6) According to (1)) The optical glass according to any one of (1) to (5), SiO₂/B₂O₃0.4 to 1.3, preferably 0.45 to 1.2, and more preferably 0.5 to 1.1; and/or BaO/La₂O₃Is 0.6 to 2, preferably 0.65 to 1.9, and more preferably 0.7 to 1.8.

(7) The optical glass according to any one of (1) to (6), wherein CaO/(BaO + SrO) is0 to 0.5, preferably 0.01 to 0.4, and more preferably 0.02 to 0.3; and/or ZnO/(CaO + SrO + BaO) is 0-0.3, preferably 0-0.2, and more preferably 0-0.15; and/or (CaO + SrO + BaO)/(La)₂O₃+Gd₂O₃+Y₂O₃) 0.7 to 2.5, preferably 0.8 to 2.3, and more preferably 0.9 to 2.1; and/or (CaO + SrO + BaO)/(Al)₂O₃+ZrO₂+TiO₂) Greater than 8, preferably greater than 10, more preferably greater than 12; and/or the SrO content is not less than the CaO content, preferably the BaO content is not less than the SrO content not less than the CaO content.

(8) The optical glass according to any one of (1) to (7), Li₂O+Na₂O+K₂O is0 to 8%, preferably 0 to 6%, more preferably 0 to 5%; and/or Li₂O/(K₂O+Na₂O) is0 to 0.5, preferably 0 to 0.4, more preferably 0 to 0.3; and/or Na₂O/K₂O is 0.2 to 5.0, preferably 0.3 to 4.0, and more preferably 0.4 to 3.0; and/or TiO₂/Nb₂O₅Is 1 or less, preferably 0.8 or less, more preferably 0.5 or less.

(9) The optical glass according to any one of (1) to (8), which has a composition comprising, in terms of weight percent: SiO 2₂: 6 to 18%, and/or B₂O₃: 12 to 25%, and/or La₂O₃: 12-30%, and/or BaO: 12-35%, and/or SrO: 0.5-15%, and/or CaO: 0 to 8%, and/or Gd₂O₃: 1 to 6%, and/or Y₂O₃: 0 to 3%, and/or ZrO₂: 0.1 to 3%, and/or Al₂O₃: 0 to 2%, and/or TiO₂: 0 to 2%, and/or Nb₂O₅: 0.1 to 5%, and/or WO₃: 0-1%, and/or ZnO: 0-3%, and/or MgO: 0 to 3%, and/or Li₂O: 0 to 3%, and/or K₂O: 0.3 to 4%, and/or Na₂O：0.5～6％。

(10) The optical glass according to any one of (1) to (9), which has a composition comprising, in terms of weight percent: SiO 2₂: 8 to 16%, and/or B₂O₃: 15-22% and/or La₂O₃: 15-28%, and/or BaO: 15-32%, and/or SrO: 1-12%, and/or CaO: 0 to 6%, and/or Gd₂O₃: 1 to 4%, and/or Y₂O₃: 1 to 3%, and/or ZrO₂: 0.1-2%, and/or Al₂O₃: 0.1 to 1%, and/or TiO₂: 0 to 1%, and/or Nb₂O₅: 0.5 to 4%, and/or K₂O: 0.5 to 3%, and/or Na₂O：1～3％。

(11) The optical glass according to any one of (1) to (10), which has a composition comprising, in terms of weight percent: ZrO (ZrO)₂: 0.1 to 1%, and/or Nb₂O₅: 1-3%, and/or SrO: 1.5 to 10 percent.

(12) The optical glass according to any one of (1) to (11), wherein the glass has a refractive index of 1.65 to 1.73, preferably 1.67 to 1.72; the Abbe number is 47 to 55, preferably 48 to 52.

(13) The optical glass according to any one of (1) to (12), wherein the glass has a temperature coefficient of refractive index of 0 or less, preferably-0.5 or less, more preferably-1.0 or less, still more preferably-2.0 or less.

(14) The optical glass according to any one of (1) to (13), wherein the glass has a water resistance stability of 4 types or more, preferably 3 types or more, more preferably 2 types or more; and/or the degree of bubbling is class A or more, preferably class A₀More preferably A or more₀₀A stage; and/or the stripes are of grade C or more, preferably grade B or more, more preferably grade A; and/or a stability against sunlight of not more than 10%, preferably not more than 8%, more preferably not more than 5% reduction in transmittance at a wavelength of 400 nm.

(15) A glass preform made of the optical glass according to any one of (1) to (14).

(16) An optical element produced from the optical glass according to any one of (1) to (14) or the glass preform according to (15).

(17) An optical device produced using the optical glass of any one of (1) to (14) or the optical element of (16).

(18) Use of the optical glass of any one of (1) to (14) or the optical element of (16) in a vehicle.

The invention has the beneficial effects that: through reasonable component design, the optical glass has medium refractive index and low temperature coefficient of refractive index, and the mass production process performance is good.

Detailed Description

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 percentage with respect 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. The term "about" as used herein means that the formulations, parameters, and other quantities and characteristics are not, and need not be, exact, and can be approximate and/or larger or smaller, if desired, reflecting tolerances, conversion factors, measurement error and the like. As used herein, "and/or" is inclusive, e.g., "A and/or B," and means A alone, B alone, or both A and B.

The optical glass mainly comprises SiO₂、B₂O₃、La₂O₃RO (R0 is one or more of MgO, CaO, SrO and BaO, the same shall apply hereinafter), Rn₂O(Rn₂0 is Li₂O、K₂O、Na₂One or more than one of O, in order toThe same below) through a reasonable component ratio, and the optical glass has a refractive index of 1.65-1.73 and an Abbe number of 47-55, and has a refractive index temperature coefficient (d-line dn/dt relative (10) within a temperature range of 20-40 DEG C^-6/° c)), excellent anti-devitrification performance, no obvious decrease in transmittance after long-term use, and is very suitable for vehicle-mounted lenses.

SiO₂And B₂O₃The glass is a network former which forms the glass of the invention, is the basis of forming the glass, and the content of the glass is closely related to key indexes of glass forming stability, devitrification resistance, refractive index, Abbe number and the like of the glass. Wherein if SiO₂The content exceeds 20 percent, the glass can be difficult to melt, the glass forming stability can be reduced, the anti-crystallization performance is reduced rapidly, and the refractive index and the Abbe number of the glass can not meet the design requirements; if SiO₂Less than 4%, the chemical stability, especially the stability against water action, of the glass is reduced, and the devitrification resistance of the glass is reduced. Thus, SiO₂The content of (B) is limited to 4 to 20%, preferably 6 to 18%, and more preferably 8 to 16%. In some embodiments, about 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20% SiO may be included₂。

B₂O₃If the content of (b) exceeds 30%, the chemical stability of the glass is lowered, and the Abbe number is higher than the design expectation; b is₂O₃If the content of (b) is less than 10%, devitrification resistance of the glass is rapidly lowered and the Abbe number of the glass is not as expected by design. Thus, B₂O₃The content of (b) is limited to 10 to 30%, preferably 12 to 25%, more preferably 15 to 22%. In some embodiments, about 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30% B may be included₂O₃。

SiO₂And B₂O₃The relative amounts of (B) will to some extent determine B₂O₃Structural state in glass, and B₂O₃The structural state of (A) has a great influence on the temperature coefficient of refractive index and chemical stability of the glass, when SiO is used₂And B₂O₃Ratio of (A) to (B) SiO₂/B₂O₃When the refractive index temperature coefficient is more than 1.3, the refractive index temperature coefficient of the glass can be rapidly increased, and the design requirement cannot be met; if SiO₂/B₂O₃When the amount is less than 0.4, the chemical stability, particularly the water resistance, of the glass rapidly decreases, and the glass cannot meet the requirements for use under severe conditions. Therefore, in the present invention, SiO₂/B₂O₃The value of (B) is preferably limited to 0.4 to 1.3. Additionally, in some embodiments, if SiO₂/B₂O₃The value of (A) is less than 0.45, the high-temperature viscosity of the glass is extremely low during the forming process, and C-level or below stripes are easily generated in the glass, so that the glass cannot be applied to an imaging system with higher requirements, if SiO is used, the glass is not easy to be used₂/B₂O₃Values of (A) higher than 1.2 make it difficult to eliminate bubbles in the glass. Thus, in some embodiments, SiO₂/B₂O₃The value of (b) is more preferably 0.45 to 1.2, and still more preferably 0.5 to 1.1. In some embodiments, the SiO₂/B₂O₃May be 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, 1.0, 1.05, 1.1, 1.15, 1.2, 1.25, 1.3.

La₂O₃The glass is an important component of the glass, and the refractive index of the glass can be rapidly improved by adding the glass into the glass, so that the glass realizes the performance of high refractive index and low dispersion. However, if the content exceeds 35%, the devitrification resistance of the glass is drastically lowered, and more seriously, the inventors have found that La₂O₃The glass has strong aggregation effect, and when the content exceeds 35 percent, the temperature coefficient of the refractive index of the glass can be rapidly increased, which is contrary to the aim of reducing the temperature coefficient of the refractive index of the glass; if the content is less than 10%, the refractive index and dispersion of the glass do not meet the design requirements, and the chemical stability, particularly the water resistance, of the glass is lowered. Thus, La₂O₃The content of (b) is limited to 10 to 35%, preferably 12 to 30%, more preferably 15 to 28%. In some embodiments, canComprising about 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35% La₂O₃。

To be at La₂O₃The glass can maintain better anti-devitrification performance even under the condition of higher content, and the inventor researches and discovers that a certain amount of Gd is added₂O₃、Y₂O₃、ZrO₂、TiO₂、Al₂O₃And the anti-crystallization performance of the glass can be improved.

Specifically, Gd₂O₃Effect on refractive index and dispersion and La₂O₃Similarly, if the content is more than 8%, the temperature coefficient of refractive index of the glass rapidly increases, the cost rapidly increases, and the devitrification resistance of the glass is rather deteriorated, so that the content is limited to 0 to 8%, preferably 1 to 6%, and more preferably 1 to 4%. In some embodiments, about 0%, greater than 0%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8% Gd may be included₂O₃。

Small amount of Y₂O₃Added into glass to replace La₂O₃The glass does not cause great changes in the refractive index and dispersion, but if the content exceeds 5%, the temperature coefficient of the refractive index of the glass rapidly rises, and the devitrification resistance of the glass is reduced. Therefore, the content is limited to 0 to 5%, preferably 0 to 3%, and more preferably 1 to 3%. In some embodiments, about 0%, greater than 0%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5% Y may be included₂O₃。

ZrO₂The invention is an optional component, the anti-devitrification performance of the glass can be improved and the chemical stability of the glass can be obviously improved by adding a small amount of the component into the glass, and meanwhile, a small amount of ZrO is added₂Can obviously reduce the erosion of molten glass to refractory materials in the production process, can prolong the service life of the furnace body and reduce the furnace bodyThe maintenance cost and the waste material discharge can obviously inhibit impurities in the refractory material from entering the glass, and the transmittance and the anti-crystallization stability of the glass are improved. However, ZrO₂In the glass of the present invention, it is harmful to lower the temperature coefficient of refractive index of the glass, and if the content exceeds 3%, the temperature coefficient of refractive index of the glass is rapidly increased and does not meet the design requirements, and at the same time, the glass becomes very difficult to melt, and the devitrification resistance is rapidly decreased, so that ZrO in the present invention is rapidly reduced₂The content is limited to 3% or less. If ZrO of₂The content of (A) is less than 0.1%, and the corrosion of the glass to the refractory material is obviously increased. Thus, ZrO in the invention₂The content is preferably 0.1 to 3%, more preferably 0.1 to 2%, and further preferably 0.1 to 1%. In some embodiments, about 0%, greater than 0%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3% ZrO may be included₂。

Small amount of Al₂O₃The additive is added into the glass, so that the devitrification resistance of the glass can be improved, and the capability of the molten glass to corrode crucible materials can be reduced. However, if the amount of the additive is more than 3%, the temperature coefficient of the refractive index of the glass increases, the melting property of the glass decreases, and the refractive index decreases rapidly. Therefore, the content is limited to 3% or less, preferably 2% or less, and more preferably 0.1 to 1%. In some embodiments, about 0%, greater than 0%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3% Al may be included₂O₃。

Small amount of TiO₂When the glass is added into glass, the sunlight-resistant stability of the glass can be improved, and the glass is particularly important for a vehicle-mounted lens to be exposed to strong ultraviolet environments such as plateaus for a long time. In addition, a small amount of TiO₂Will be liftedDevitrification resistance of the glass. But TiO 2₂This is detrimental to the reduction of the temperature coefficient of refraction for the bulk glass. After a lot of experimental studies by the inventor, it is found that if the content exceeds 3%, the temperature coefficient of refractive index of the glass does not meet the design requirement, therefore, TiO in the invention₂The content is 3% or less, preferably 0 to 2%, more preferably 0 to 1%. In some embodiments, about 0%, greater than 0%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3% TiO may be included₂。

Nb₂O₅、WO₃The glass belongs to high-refraction and high-dispersion oxide, and the addition of the oxide into the glass can adjust the refractive index and dispersion of the glass and improve the chemical stability of the glass. The inventor researches to find that in the glass, the capacity of the two oxides for improving the temperature coefficient of the refractive index of the glass is slower than that of other high-refractive-index high-dispersion oxides, such as TiO₂、Bi₂O₃、Ta₂O₅PbO, etc. These two highly dispersive oxides are ideal oxides for increasing the dispersion of the glass from the viewpoint of lowering the temperature coefficient of refractive index of the glass of the present invention. If Nb₂O₅The content of (A) exceeds 5%, the Abbe number of the glass is rapidly reduced and does not meet the design requirement, and the devitrification resistance of the glass is rapidly reduced, so that the Nb content in the invention₂O₅The content of (B) is limited to 5% or less. If Nb₂O₅Less than 0.1%, this means that more WO needs to be added₃Or other highly dispersed oxides as described above, which leads to a decrease in the glass transmittance or a rapid increase in the temperature coefficient of refractive index, and therefore Nb₂O₅The content of (b) is preferably 0.1 to 5%, more preferably 0.5 to 4%, and further preferably 1 to 3%. In some embodiments, about 0%, greater than 0%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1 may be included.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3% Nb₂O₅。

WO₃Can replace Nb in small amount₂O₅When the content exceeds 2%, the transmittance of the glass is remarkably reduced. Therefore, the content is limited to 2% or less, preferably 1% or less, and more preferably not incorporated. In some embodiments, about 0%, greater than 0%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2% of WO may be included₃。

Furthermore, the glass provided by the invention is mainly used in the open air severe environment, such as a vehicle-mounted lens, a security lens and the like, and can be exposed to sunlight for a long time, especially in a plateau area. The traditional optical glass is designed for photographic equipment, and the problem of the transmittance reduction of the glass after long-term exposure is not generally considered. Therefore, how to improve the sunlight-resistant stability of the glass is a key issue to be focused on by the glass of the present invention.

After a plurality of experiments, the inventor finds that in some embodiments, Nb₂O₅And TiO₂The simultaneous use of TiO is more likely than the single use of TiO₂The effect of improving the sunlight-resistant stability of the glass is more obvious. However, when TiO₂And Nb₂O₅Ratio of (3) TiO₂/Nb₂O₅Above 1, the solar stability of the glass is no longer improved, but the temperature coefficient of refractive index rises more rapidly, which is contrary to the goal of obtaining a lower temperature coefficient of refractive index. Therefore, to obtain a glass with a lower temperature coefficient of refractive index and strong stability against sunlight, TiO₂/Nb₂O₅The value of (b) is 1 or less, preferably 0.8 or less, and more preferably 0.5 or less. In some embodiments, the TiO₂/Nb₂O₅May be 0, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, 1.

For the glass of the system, ZnO is added into the glass, so that the chemical stability of the glass can be improved, and the high-temperature viscosity of the glass is reduced, thereby reducing the production difficulty of the glass. However, the inventors have studied and found that if the content of ZnO exceeds 5%, the temperature coefficient of refractive index of the glass rapidly decreases. Therefore, the content is limited to 5% or less, preferably 3% or less, and more preferably not incorporated. In some embodiments, about 0%, greater than 0%, 0.1%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5% ZnO may be included.

BaO, CaO, SrO and MgO are alkaline earth metal oxides, and when the BaO, the CaO, the SrO and the MgO are added into glass, the refractive index and the dispersion of the glass can be adjusted, the stability of the glass is enhanced, and the devitrification resistance of the glass is improved. The common technical literature recognizes that the role of oxides of the same family in such glasses is essentially the same. However, through many experiments, the inventors found that the effects of the above alkaline earth oxides are very different from the temperature coefficient of refractive index, chemical stability and devitrification resistance which are most concerned by the glass of the present system.

BaO has the strongest capacity of reducing the temperature coefficient of the refractive index of the glass, so the content of the BaO is limited to more than 10 percent to achieve the temperature coefficient of the refractive index expected by the invention; however, if the content exceeds 40%, the chemical stability, particularly the water resistance, of the glass is rapidly lowered, and the devitrification resistance of the glass is also rapidly lowered. Therefore, the content is limited to 10 to 40%, preferably 12 to 35%, and more preferably 15 to 32%. In some embodiments, about 10%, 11%, 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% BaO may be included.

SrO is more strongly reduced in the temperature coefficient of refractive index than CaO but is less strongly reduced than BaO, and when it is added to a glass, the glass is less strongly chemically stable than BaO, and when the content of SrO exceeds 15%, the devitrification resistance of the glass is rather rapidly deteriorated, and the temperature coefficient of refractive index of the glass rapidly increases, so that the content thereof is 15% or less. On the other hand, a large number of experimental researches show that when BaO is higher than 15%, the water resistance and the anti-crystallization stability of the glass can be obviously improved by adding more than 0.5% of SrO, and meanwhile, the temperature coefficient of the refractive index of the glass cannot be obviously increased. Therefore, in the present invention, the SrO content is preferably 0.5 to 15%, more preferably 1 to 12%, and still more preferably 1.5 to 10%. In some embodiments, about 0%, greater than 0%, 0.1%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, 10.5%, 11%, 11.5%, 12%, 12.5%, 13%, 13.5%, 14%, 14.5%, 15% SrO may be included.

Generally, CaO is an essential component in lanthanum crown glass, and the addition of CaO into glass can improve the refractive index and dispersion of glass, significantly reduce the density of glass, lighten the lens, reduce the high-temperature viscosity and surface tension of glass, and reduce the production difficulty of glass. However, CaO is inferior to BaO and SrO in the ability of the glass to lower the temperature coefficient of refractive index of the glass of the present system, and therefore is preferably not incorporated from the viewpoint of lowering the temperature coefficient of refractive index. However, since CaO is the weakest in the above three alkaline earth metal oxides in its ability to deteriorate water resistance, it may be added in an appropriate amount from the viewpoint of improving the water resistance of the glass. Therefore, the CaO content is limited to 0 to 10%, preferably 0 to 8%, and more preferably 0 to 6%. In some embodiments, about 0%, greater than 0%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10% CaO may be included.

For the glass of the present system, MgO is detrimental to lowering the temperature coefficient of refractive index of the glass, but a small amount of MgO can improve the water resistance and stability of the glass. If the content exceeds 5%, the temperature coefficient of the refractive index of the glass cannot meet the design requirement, and the devitrification resistance of the glass is rapidly reduced. Therefore, the content is limited to 5% or less, preferably 3% or less, and more preferably not incorporated. In some embodiments, MgO may be included at about 0%, greater than 0%, 0.1%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%.

More importantly, the inventors have found that, in some embodiments, when all three alkaline earth oxides of BaO, CaO and SrO are added, the glass undergoes a complex synergistic effect, the performance does not change linearly with the addition of a single substance, and when the CaO/(BaO + SrO) value exceeds 0.5, although the chemical stability of the glass is improved to some extent, the temperature coefficient of refractive index of the glass rapidly increases, and the devitrification resistance of the glass rapidly decreases, so the CaO/(BaO + SrO) value in the present invention is preferably 0 to 0.5. In some embodiments, the value of CaO/(BaO + SrO) is more preferably 0.01 to 0.4, and even more preferably 0.02 to 0.3, and the temperature coefficient of refractive index, chemical stability, and devitrification resistance of the glass can all meet the design expectations. In some embodiments, the CaO/(BaO + SrO) value may be 0, greater than 0, 0.01, 0.02, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5.

In some embodiments, to achieve a lower temperature index, it is preferred to satisfy the BaO content ≧ CaO content, further satisfy the SrO content ≧ CaO content, and further satisfy the BaO content ≧ SrO content ≧ CaO content.

When ZnO is added to a glass system to enhance the chemical stability of the glass, it is necessary to take into consideration the problem of the increase in temperature coefficient of refractive index due to the addition of ZnO. The inventors have investigated that in some embodiments, the value of ZnO/(CaO + BaO + SrO) may have an effect on the temperature coefficient of refractive index and the chemical stability of the glass. When the value of ZnO/(CaO + BaO + SrO) is greater than 0.3, the chemical stability of the glass hardly increases, but the temperature coefficient of refractive index of the glass sharply increases. Therefore, in order to obtain a glass having a good chemical stability and a low temperature coefficient of refractive index, the value of ZnO/(CaO + BaO + SrO) should be preferably 0.3 or less, more preferably 0.2 or less, and still more preferably 0.15 or less. In some embodiments, the value of ZnO/(CaO + BaO + SrO) may be 0, greater than 0, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.2, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, 0.3.

Li₂O、Na₂O、K₂O belongs to alkali metal oxide, and the addition of proper amount can reduce the temperature coefficient of the refractive index of the glass, but the chemical stability and the anti-devitrification performance of the glass can be rapidly reduced. The inventor finds out through a large number of experiments that:

1) in the glass of the system of the invention, the temperature coefficient of refractive index of the glass does not linearly decrease along with the increase of the alkali metal oxide, but the temperature coefficient of refractive index does not decrease after reaching an extreme value, but the devitrification resistance of the glass is rapidly deteriorated by continuously adding the alkali metal oxide at the extreme value. In some embodiments, Li₂O、Na₂O and K₂Sum of contents of O Li₂O+Na₂O+K₂If the value of O exceeds 8%, the temperature coefficient of refractive index of the glass is not lowered any more, and the devitrification resistance and the water resistance are drastically lowered.

From the production point of view, it is desirable that the lower the high-temperature viscosity at the time of clarification, the more advantageous the discharge of bubbles, and therefore, when the temperature coefficient of refractive index, water resistance and devitrification resistance of the glass meet the design requirements, the alkali metal oxide may be added in an amount of not more than 8%, so as to raise the high-temperature viscosity of the glass and raise the level of the bubble degree of the glass at the time of mass production. Thus, Li₂O+Na₂O+K₂The total amount of O is controlled to 8% or less, preferably 6% or less, and more preferably 5% or less. In some embodiments, Li₂O+Na₂O+K₂The total amount of O may be about 0%, greater than 0%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%.

2) When all three alkali metal oxides are present together, a synergistic effect is produced, in some embodiments, if Li is present₂O/(K₂O+Na₂O) value greater than 0.5, the temperature coefficient of refractive index of the glass is substantially unchanged, but the devitrification resistance and chemical stability of the glass are drastically reduced, and therefore, Li₂O/(K₂O+Na₂O) is preferably less than 0.5, more preferably less than 0.4, and still more preferably less than 0.3. In some embodiments, Li₂O/(K₂O+Na₂O) may have a value of 0, greater than 0, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5.

The inventors have also found that K is a factor for lowering the temperature coefficient of refractive index₂O and Na₂O is stronger and Li₂O times; from the viewpoint of destroying the chemical stability of the glass, K₂O and Na₂O is stronger and Li₂O times; li in terms of resistance to devitrification which deteriorates the glass₂Strongest O, K₂O and Na₂And O times. Therefore, in order to obtain a temperature coefficient of refractive index, chemical stability and anti-devitrification performance that satisfy the design expectations, how to select an appropriate kind and an appropriate amount of alkali metal oxide requires extensive experimental studies to determine. From the single-component alkali metal oxides, if Na₂The content of O exceeds 8%, and the devitrification resistance and chemical stability of the glass are drastically lowered, so that the content is limited to 0 to 8%, preferably 0.5 to 6%, and more preferably 1 to 3% in some embodiments. In some embodiments, if K₂The content of O is higher than 6%, and the devitrification resistance and the chemical stability of the glass are rapidly reduced, so that the content is limited to 0 to 6%, preferably 0.3 to 4%, and more preferably 0.5 to 3%. In some embodiments, Li₂When the content of O exceeds 5%, the devitrification resistance of the glass is rapidly lowered, and therefore the content is preferably 5% or less, more preferably 3% or less, and further preferably not incorporated. In some embodiments, Li₂The content of O may be about 0%, greater than 0%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%. In some embodiments, Na₂The content of O may be about 0%, greater than 0%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%. In some embodiments, K₂The content of O may be about 0%, more than 0%, 0.3%, 0.5%、1％、1.5％、2％、2.5％、3％、3.5％、4％、4.5％、5％、5.5％、6％。

The inventors have conducted extensive studies to find that, in some embodiments, Na is present in the glass₂O/K₂The proportion of O is greatly related to the bubble degree and water resistance of the glass when Na is used₂O/K₂When the value of O is more than 5.0, the water resistance of the glass is sharply reduced; when Na is present₂O/K₂When the value of O is less than 0.2, the bubble degree of the glass rapidly decreases. Thus, Na₂O/K₂When the value of O is in the range of 0.2 to 5.0, preferably 0.3 to 4.0, and more preferably 0.4 to 3.0, the glass can have excellent bubble content and water resistance. In some embodiments, Na₂O/K₂The value of O may be 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.2, 1.4, 1.5, 1.6, 1.8, 2.0, 2.2, 2.4, 2.5, 2.6, 2.8, 3.0, 3.2, 3.4, 3.5, 3.6, 3.8, 4.0, 4.2, 4.4, 4.5, 4.6, 4.8, 5.0.

In the glass of the present invention, the total content of the alkaline earth metal oxides such as BaO, SrO and CaO and La are₂O₃、Gd₂O₃、Y₂O₃The ratio of the total content of (A) has a large relationship with the temperature coefficient of refractive index, devitrification resistance and water resistance of the glass. In some embodiments, when (BaO + SrO + CaO)/(La)₂O₃+Gd₂O₃+Y₂O₃) When the value of (A) is more than 2.5, the temperature coefficient of refractive index of the glass does not decrease any more, and the water resistance of the glass decreases rapidly; when (BaO + SrO + CaO)/(La)₂O₃+Gd₂O₃+Y₂O₃) When the refractive index is less than 0.7, the water resistance of the glass is improved, but the temperature coefficient of the refractive index of the glass is rapidly increased, and the devitrification resistance of the glass is rapidly reduced. Therefore, to obtain glass with low temperature coefficient of refractive index, water resistance meeting design requirements, and good devitrification resistance, the requirement of (BaO + SrO + CaO)/(La) is met₂O₃+Gd₂O₃+Y₂O₃) The value of (b) is 0.7 to 2.5, preferably 0.8 to 2.3, and more preferably 0.9 to 2.1. In some embodiments, (BaO + SrO + CaO)/(La)₂O₃+Gd₂O₃+Y₂O₃) The value of (b) may be 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, 2.3, 2.4, 2.5.

In the glass of the system of the invention, BaO and La₂O₃The glass is mainly composed, and researches show that the ratio of the main components to the glass has a large correlation with the temperature coefficient of the refractive index of the glass, the water resistance of the glass and the devitrification resistance of the glass. In some embodiments, when BaO, La₂O₃Content ratio of BaO/La₂O₃When the refractive index temperature coefficient is more than 2, the refractive index temperature coefficient of the glass is not reduced any more, but the water resistance of the glass is reduced rapidly; when BaO/La₂O₃When the value of (A) is less than 0.6, the water resistance of the glass is greatly improved, but the temperature coefficient of refractive index of the glass does not meet the design requirement, and the devitrification resistance of the glass is rapidly deteriorated, and even the devitrification occurs during the melting process. Thus, BaO/La₂O₃The value of (b) is limited to 0.6 to 2, preferably 0.65 to 1.9, and more preferably 0.7 to 1.8. In some embodiments, BaO/La₂O₃The value of (b) can be 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, 1.0, 1.05, 1.1, 1.15, 1.2, 1.25, 1.3, 1.35, 1.4, 1.45, 1.5, 1.55, 1.6, 1.65, 1.7, 1.75, 1.8, 1.85, 1.9, 1.95, 2.0.

The inventors have discovered that, in some embodiments, (CaO + BaO + SrO)/(Al)₂O₃+ZrO₂+TiO₂) The value of (A) is strongly correlated with the temperature coefficient of refractive index of the glass. When (CaO + BaO + SrO)/(Al)₂O₃+ZrO₂+TiO₂) When the value of (A) is less than 8, the chemical stability and devitrification resistance of the glass are slightly improved, but the temperature coefficient of the refractive index of the glass is sharply increased, and the design requirements cannot be met. Thus, (CaO + BaO + SrO)/(Al)₂O₃+ZrO₂+TiO₂) The value of (b) should be greater than 8, preferably greater than 10, more preferably greater than 12.

Sb₂O₃、SnO₂SnO and CeO₂One or more of the components can be added as clarifying agentAdding Sb in an amount₂O₃、SnO₂、CeO₂The component can improve the fining effect of the glass, but when Sb is used₂O₃When the content exceeds 2%, the glass tends to have a reduced fining property and the deterioration of the forming mold is promoted by the strong oxidation thereof, so that Sb in the present invention₂O₃The amount of (b) is 2% or less, preferably 1% or less, more preferably 0.5% or less. SnO₂SnO may be added as a fining agent, but when the content exceeds 2%, the glass is colored, or when the glass is heated, softened and press-molded again, Sn tends to become a starting point of nucleation and devitrification occurs, so that the SnO of the present invention₂And SnO are contained in an amount of 2% or less, preferably 1% or less, more preferably 0.5% or less, and further preferably not incorporated. CeO (CeO)₂Action and addition amount ratio of (B) and SnO₂The content is 2% or less, preferably 1% or less, more preferably 0.5% or less, and further preferably no incorporation. In some embodiments, one or more of the above 4 fining agents are present in an amount of about 0%, greater than 0%, 0.1%, 0.2%, 0.3%, 0.4%, 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%.

In some embodiments, As may also be used₂O₃A compound of Cl, a compound of Br, etc. As a clarifying agent, the content thereof is 2% or less, preferably 1% or less, more preferably 0.5% or less, respectively, but it is preferable not to introduce As from the viewpoint of environmental protection and the like₂O₃. In some embodiments, one or more of the above 3 fining agents are present in an amount of about 0%, greater than 0%, 0.1%, 0.2%, 0.3%, 0.4%, 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%.

[ regarding components that should not be contained ]

If necessary, other components not mentioned above can be added within a range not impairing the characteristics of the glass of the present invention. However, since the glass is colored and absorbs at a specific wavelength in the visible light region even when a small amount of a transition metal component such as V, Cr, Mn, Fe, Co, Ni, Cu, Ag, and Mo is contained alone or in combination, thereby reducing the property of the present invention to improve the effect of the visible light transmittance, it is preferable that the optical glass, which requires transmittance at a wavelength in the visible light region, is not substantially contained.

In recent years, cations of Pb, Th, Cd, Tl, Os, Be, and Se tend to Be used as harmful chemical substances in a controlled manner, 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 introduced", "not containing" or "0%" as used herein means that the compound, molecule or element is not intentionally added as a raw material to the optical glass of the present invention; however, it is 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 optical glass and may be contained in the final optical glass in small or trace amounts.

The performance of the optical glass of the present invention will be described below.

[ refractive index and Abbe number ]

Refractive index (nd) and Abbe number (v) of optical glass_d) The test was carried out according to the method specified in GB/T7962.1-2010.

The refractive index (nd) of the optical glass is within the range of 1.65-1.73, and the preferable range is 1.67-1.72; abbe number (v) of the glass of the invention_d) The range of (A) is 47 to 55, preferably 48 to 52.

[ temperature coefficient of refractive index ]

The temperature coefficient of refractive index (d-line dn/dt relative (10-6/. degree. C.)) of the optical glass was measured in the range of 20 to 40 ℃ by the method prescribed in GB/T7962.4-2010

The temperature coefficient of refractive index (dn/dt) of the optical glass of the present invention is0 or less, preferably-0.5 or less, more preferably-1.0 or less, and further preferably-2.0 or less.

[ stability against Water action ]

Stability of optical glass to Water action D_w(powder method) the test was carried out according to the method prescribed in GB/T17129.

The stability of the optical glass against water action D_wIs 4 types or more, preferably 3 types or more, and more preferably 2 types or more.

[ degree of bubbling ]

The bubble degree of the optical glass is tested according to the method specified in GB/T7962.8-2010.

The optical glass of the present invention has a bubble degree of class A or more, preferably class A₀More preferably A or more₀₀And (4) stages.

[ degree of striae ]

The degree of striae of the glass of the present invention was measured according to the method specified in MLL-G-174B. The method is that a fringe instrument composed of a point light source and a lens is used for comparing and checking with a standard sample from the direction of most easily seeing the fringes, the 4 grades are respectively A, B, C, D grades, A grade is the fringe without being seen by naked eyes under the specified detection condition, B grade is the fringe with fineness and dispersion under the specified detection condition, C grade is the slight parallel fringe under the specified detection condition, and D grade is the rough fringe under the specified detection condition.

The optical glass of the present invention has a striae of class C or more, preferably class B or more, and more preferably class a.

[ solar radiation resistance ]

The sunlight-resistant stability of the optical glass is determined by irradiating a 10mm thick sample for 4 hours under the standard conditions of JOGIS04-1994, and comparing the spectral transmittance curves before and after irradiation to determine the attenuation of the glass in the 400nm band. The spectral transmittance curve of the glass was measured using a spectrophotometer.

The solar stability of the optical glass of the present invention is such that the transmittance at a wavelength of 400nm decreases by not more than 10%, preferably not more than 8%, and more preferably not more than 5%.

[ anti-devitrification Property ]

The method for testing the anti-devitrification performance of the optical glass comprises the following steps: cutting the sample glass into 20 × 20 × 10mm, and placing at temperature T_gKeeping the temperature in a muffle furnace at +230 ℃ for 30 minutes, taking out the muffle furnace, putting the muffle furnace into heat-preservation cotton, slowly cooling the muffle furnace, and observing the surface crystallization condition after cooling.

The sample glass of the optical glass of the invention is cut into the specification of 20 multiplied by 10mm, and the putting temperature is T_gKeeping the temperature in a muffle furnace at +230 ℃ for 30 minutes, taking out the muffle furnace, putting the muffle furnace into heat-preservation cotton, and slowly cooling without obvious crystallization on the surface. The surface without obvious crystallization in the invention means that: the surface has no crystallization spots or crystallization spots, but the area of the surface accounts for less than 5 percent of the whole area and the crystallization depth does not exceed 0.5 mm.

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

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 prefabricated member has the characteristics of medium refractive index and lower refractive index temperature coefficient; the optical element of the present invention has the temperature coefficient characteristics of medium refractive index and low refractive index, and can provide various optical elements such as lenses and prisms having high optical values.

Examples of the lens include 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.

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.

The optical glass has the properties of excellent chemical stability, lower refractive index temperature coefficient and the like, and is particularly suitable for being applied to the fields of vehicle-mounted monitoring and security protection and the like.

In order to further understand the technical solution of the present invention, examples of the optical glass of the present invention will be described below. It should be noted that these examples do not limit the scope of the present invention.

[ optical glass examples ]

The optical glasses (examples 1 to 20) shown in tables 2 to 3 were produced by weighing and mixing common raw materials for glass (such as oxides, hydroxides, carbonates, nitrates, etc.) in the ratios of the respective examples shown in the tables, placing the mixed raw materials in a platinum crucible, melting at 1300 to 1350 ℃ for 2.5 to 4 hours, clarifying, stirring and homogenizing to obtain a homogeneous molten glass free of bubbles and containing no undissolved substances, and casting and annealing the molten glass in a mold.

Examples 1 to 20 show the composition and refractive index (nd) of the optical glass; abbe number (v)_d) (ii) a A temperature coefficient of refractive index (d-line dn/dt relative) (10) in the range of 20 to 40 DEG C^-6/° c)) (dn/dt); stability to Water action by powder method (D)_w) (ii) a Cutting the sample glass into 20 × 20 × 10mm, and placing at temperature T_gKeeping the temperature in a muffle furnace at +230 ℃ for 30 minutes, taking out the muffle furnace, placing the muffle furnace into heat-preservation cotton for slow cooling, and observing the surface crystallization condition after cooling, wherein no obvious crystallization is marked as 'A', and the obvious crystallization is marked as 'B'; the bubble degree and the streak degree are expressed according to the standard specification; the percent decrease in transmittance at a wavelength of 400nm after the sunshine resistance stability test is represented by "Δ T (%)".

SiO₂/B₂O₃Is denoted by K1; TiO 2₂/Nb₂O₅Is denoted by K2; the CaO/(BaO + SrO) value is represented by K3; the value of ZnO/(CaO + BaO + SrO) is represented by K4; li₂O+Na₂O+K₂The total amount of O is represented by K5; li₂O/(K₂O+Na₂O) is represented by K6; na (Na)₂O/K₂The O value is represented by K7; (BaO + SrO + CaO)/(La)₂O₃+Gd₂O₃+Y₂O₃) Is denoted by K8; BaO/La₂O₃Is denoted by K9; (CaO + BaO + SrO)/(Al)₂O₃+ZrO₂+TiO₂) Is denoted by K10.

TABLE 2

TABLE 3

[ glass preform examples ]

The optical glasses obtained in examples 1 to 10 in table 2 were cut into a predetermined size, and then a release agent was uniformly applied to the surface of the optical glass, followed by heating, softening, and press-molding to prepare preforms of various lenses and prisms 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.

[ optical element examples ]

The preforms obtained from the above glass preform examples were annealed to reduce the internal deformation of the glass and to perform fine adjustment so that the optical properties such as refractive index and the like could be brought to desired values.

Next, each preform is ground and polished to produce various lenses 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, and prisms. The surface of the optical element may be coated with an antireflection film.

Claims

1. Optical glass, characterized in that its composition comprises SiO₂、B₂O₃、La₂O₃RO and Rn₂O, wherein RO is one of MgO, CaO, SrO and BaON is₂O is Li₂O、K₂O and Na₂More than one of O, SiO₂：4～20%、B₂O₃：10～30%、La₂O₃: 10-35%, BaO: 10-40%, the refractive index of the glass is 1.65-1.73, the Abbe number is 47-55, the temperature coefficient of the refractive index is less than or equal to 0, and the composition is expressed by weight percentage, wherein BaO/La₂O₃0.6 to 1.95 of SiO₂/B₂O₃0.45 to 1.2 of Na₂O/K₂O is 0.2 to 5.0, and the bubble degree is at least class A.

2. An optical glass according to claim 1, characterised in that its composition, expressed in weight percentage, comprises: SrO: 0-15%, CaO: 0-10%, MgO: 0 to 5% of Li₂O：0～5%、K₂O：0～6%、Na₂O：0～8%、Gd₂O₃：0～8%、Y₂O₃：0～5%、ZrO₂：0～3%、Al₂O₃：0～3%、TiO₂：0～3%、Nb₂O₅：0～5%、WO₃: 0-2%, ZnO: 0-5% of a clarifying agent: 0 to 2 percent.

3. Optical glass, characterized in that its composition, expressed in weight percentages, contains: SiO 2₂：4～20%、B₂O₃：10～30%、La₂O₃：10～35%、BaO：10～40%、SrO：0～15%，BaO/La₂O₃0.6 to 1.95 of SiO₂/B₂O₃0.45 to 1.2 of Na₂O/K₂O is 0.2-5.0, and the temperature coefficient of the refractive index is less than or equal to 0.

4. The optical glass of claim 3, further comprising: CaO: 0-10%, MgO: 0 to 5% of Li₂O：0～5%、K₂O：0～6%、Na₂O：0～8%、Gd₂O₃：0～8%、Y₂O₃：0～5%、ZrO₂：0～3%、Al₂O₃：0～3%、TiO₂：0～3%、Nb₂O₅：0～5%、WO₃: 0-2%, ZnO: 0-5% of a clarifying agent: 0 to 2 percent.

5. Optical glass, characterized in that its composition, expressed in weight percentage, consists of SiO₂：4～20%、B₂O₃：10～30%、La₂O₃：10～35%、BaO：10～40%、SrO：0～15%、CaO：0～10%、MgO：0～5%、Rn₂O ：0～8%、Gd₂O₃：0～8%、Y₂O₃：0～5%、ZrO₂：0～3%、Al₂O₃：0～3%、TiO₂：0～3%、Nb₂O₅：0～5%、WO₃: 0-2%, ZnO: 0 to 5%, wherein Rn₂O is Li₂O、K₂O、Na₂More than one of O, BaO/La₂O₃0.6 to 1.95 of SiO₂/B₂O₃0.45 to 1.2 of Na₂O/K₂O is 0.2 to 5.0.

6. An optical glass according to any of claims 1 to 5, wherein the SiO is₂/B₂O₃0.45 to 1.15; and/or BaO/La₂O₃0.65 to 1.9.

7. An optical glass according to any of claims 1 to 5, wherein the SiO is₂/B₂O₃0.45 to 1.1; and/or BaO/La₂O₃0.7 to 1.8.

8. An optical glass according to any of claims 1 to 5, wherein the SiO is₂/B₂O₃0.5 to 1.1.

9. An optical glass according to any one of claims 1 to 5, wherein CaO/(BaO + SrO) is0 to 0.5; and/or ZnO/(CaO + SrO + BaO) is 0-0.3; and/or (CaO + SrO + BaO)/(La)₂O₃+Gd₂O₃+Y₂O₃) 0.7 to 2.5; and/or (CaO + SrO + BaO)/(Al)₂O₃+ZrO₂+TiO₂) Greater than 8; and/or the content of SrO is more than or equal to the content of CaO.

10. An optical glass according to any one of claims 1 to 5, wherein CaO/(BaO + SrO) is 0.01 to 0.4; and/or ZnO/(CaO + SrO + BaO) is 0-0.2; and/or (CaO + SrO + BaO)/(La)₂O₃+Gd₂O₃+Y₂O₃) 0.8 to 2.3; and/or (CaO + SrO + BaO)/(Al)₂O₃+ZrO₂+TiO₂) Greater than 10; and/or the BaO content is more than or equal to the SrO content and more than or equal to the CaO content.

11. An optical glass according to any one of claims 1 to 5, wherein CaO/(BaO + SrO) is 0.02 to 0.3; and/or ZnO/(CaO + SrO + BaO) is 0-0.15; and/or (CaO + SrO + BaO)/(La)₂O₃+Gd₂O₃+Y₂O₃) 0.9 to 2.1; and/or (CaO + SrO + BaO)/(Al)₂O₃+ZrO₂+TiO₂) Greater than 12.

12. An optical glass according to any one of claims 1 to 5, wherein Li₂O+Na₂O+K₂O is 0-8%; and/or Li₂O/（K₂O+Na₂O) is0 to 0.5; and/or TiO₂/Nb₂O₅Is 1 or less.

13. An optical glass according to any one of claims 1 to 5, wherein Li₂O+Na₂O+K₂O is 0-6%; and/or Li₂O/（K₂O+Na₂O) is0 to 0.4; and/or Na₂O/K₂O is 0.3 to 4.0; and/or TiO₂/Nb₂O₅Is 0.8 or less.

14. An optical glass according to any one of claims 1 to 5, wherein Li₂O+Na₂O+K₂O is 0-5%; and/or Li₂O/（K₂O+Na₂O) is0 to 0.3; and/or Na₂O/K₂O is 0.4 to 3.0; and/or TiO₂/Nb₂O₅Is 0.5 or less.

15. An optical glass according to any one of claims 1 to 5, having a composition comprising, in weight percent: SiO 2₂: 6 to 18%, and/or B₂O₃: 12 to 25%, and/or La₂O₃: 12-30%, and/or BaO: 12-35%, and/or SrO: 0.5-15%, and/or CaO: 0 to 8%, and/or Gd₂O₃: 1 to 6%, and/or Y₂O₃: 0 to 3%, and/or ZrO₂: 0.1 to 3%, and/or Al₂O₃: 0 to 2%, and/or TiO₂: 0 to 2%, and/or Nb₂O₅: 0.1 to 5%, and/or WO₃: 0-1%, and/or ZnO: 0-3%, and/or MgO: 0 to 3%, and/or Li₂O: 0 to 3%, and/or K₂O: 0.3 to 4%, and/or Na₂O：0.5～6%。

16. An optical glass according to any one of claims 1 to 5, having a composition comprising, in weight percent: SiO 2₂: 8 to 16%, and/or B₂O₃: 15-22% and/or La₂O₃: 15-28%, and/or BaO: 15-32%, and/or SrO: 1-12%, and/or CaO: 0 to 6%, and/or Gd₂O₃: 1 to 4%, and/or Y₂O₃: 1 to 3%, and/or ZrO₂: 0.1-2%, and/or Al₂O₃: 0.1 to 1%, and/or TiO₂: 0 to 1%, and/or Nb₂O₅: 0.5 to 4%, and/or K₂O: 0.5 to 3%, and/or Na₂O：1～3%。

17. Light according to any one of claims 1 to 5Chemical glass, characterized in that its composition, expressed in weight percentages, comprises: ZrO (ZrO)₂: 0.1 to 1%, and/or Nb₂O₅: 1-3%, and/or SrO: 1.5 to 10 percent.

18. An optical glass according to any one of claims 3 to 5, wherein the glass has a refractive index of from 1.65 to 1.73; the Abbe number is 47-55.

19. An optical glass according to any one of claims 1 to 5, wherein the glass has a refractive index of 1.67 to 1.72; the Abbe number is 48-52.

20. An optical glass according to claim 5, characterised in that the glass has a temperature coefficient of refractive index of 0 or less.

21. An optical glass according to any one of claims 1 to 5, wherein the glass has a temperature coefficient of refractive index of-0.5.

22. An optical glass according to any one of claims 1 to 5, wherein the glass has a temperature coefficient of refractive index of-1.0 or less.

23. An optical glass according to any of claims 1 to 5, wherein the glass has a temperature coefficient of refractive index of-2.0 or less.

24. An optical glass according to any one of claims 1 to 5, wherein the water-resistant stability of the glass is of at least 4 types; the bubble degree is more than A level; and/or the stripes are above grade C; and/or a stability against sunlight of not more than 10% decrease in transmittance at a wavelength of 400 nm.

25. An optical glass according to any one of claims 1 to 5, wherein the water-resistant stability of the glass is of 3 or more types; and/or a degree of bubbling of A₀More than grade; and/or stripsThe pattern is more than B level; and/or a reduction in the transmission at a wavelength of 400nm of not more than 8% in the stability against sunlight.

26. An optical glass according to any one of claims 1 to 5, wherein the water-resistant stability of the glass is 2 or more types; and/or a degree of bubbling of A₀₀A stage; and/or the stripes are class A; and/or a reduction in the transmission at a wavelength of 400nm of not more than 5% in the stability against sunlight.

27. A glass preform made of the optical glass as claimed in any one of claims 1 to 26.

28. An optical element produced from the optical glass according to any one of claims 1 to 26 or the glass preform according to claim 27.

29. An optical device comprising the optical glass according to any one of claims 1 to 26 or the optical element according to claim 28.

30. Use of an optical glass according to any one of claims 1 to 26 or an optical element according to claim 28 in a vehicle.